The Langmuir adsorption model explains adsorption by assuming an adsorbate behaves as an ideal gas at isothermal conditions. According to the model, adsorption and desorption are reversible processes. This model even explains the effect of pressure i.e. at these conditions the adsorbate's partial pressure, , is related to the volume of it, , adsorbed onto a solid adsorbent. The adsorbent, as indicated in the figure, is assumed to be an ideal solid surface composed of a series of distinct sites capable of binding the adsorbate.  The adsorbate binding is treated as a chemical reaction between the adsorbate gaseous molecule  and an empty sorption site, . This reaction yields an adsorbed species  with an associated equilibrium constant :

 A_{g}{} + S <=> A_{ad}

From these basic hypotheses the mathematical formulation of the Langmuir adsorption isotherm can be derived in various independent and complementary ways: by the kinetics, the thermodynamics, and the statistical mechanics approaches respectively (see below for the different demonstrations).

The Langmuir adsorption equation is the following:

where  is the fractional occupancy of the adsorption sites, i.e., the ratio of , the volume of gas adsorbed onto the solid, to , the volume of a gas molecules monolayer covering the whole surface of the solid and completely occupied by the adsorbate. A continuous monolayer of adsorbate molecules covering a homogeneous flat solid surface is the conceptual basis for this adsorption model.

Background and experiments
In 1916, Irving Langmuir presented his model for the adsorption of species onto simple surfaces.  Langmuir was awarded the Nobel Prize in 1932 for his work concerning surface chemistry.  He hypothesized that a given surface has a certain number of equivalent sites to which a species can “stick”, either by physisorption or chemisorption. His theory began when he postulated that gaseous molecules do not rebound elastically from a surface, but are held by it in a similar way to groups of molecules in solid bodies.

Langmuir published two papers that confirmed the assumption that adsorbed films do not exceed one molecule in thickness. The first experiment involved observing electron emission from heated filaments in gases. The second, a more direct evidence, examined and measured the films of liquid onto an adsorbent surface layer. He also noted that generally the attractive strength between the surface and the first layer of adsorbed substance is much greater than the strength between the first and second layer.  However, there are instances where the subsequent layers may condense given the right combination of temperature and pressure.

Basic assumptions of the model

Inherent within this model, the following assumptions are valid specifically for the simplest case: the adsorption of a single adsorbate onto a series of equivalent sites onto the surface of the solid.

 The surface containing the adsorbing sites is a perfectly flat plane with no corrugations (assume the surface is homogeneous). However, chemically heterogeneous surfaces can be considered to be homogeneous if the adsorbate is bound to only one type of functional groups on the surface.
 The adsorbing gas adsorbs into an immobile state.
 All sites are energetically equivalent and the energy of adsorption is equal for all sites.
 Each site can hold at most one molecule of A (mono-layer coverage only).
 No (or ideal) interactions between adsorbate molecules on adjacent sites. When the interactions are ideal, the energy of side-to-side interactions is equal for all sites regardless of the surface occupancy.

Derivations of the Langmuir adsorption isotherm
The mathematical expression of the Langmuir adsorption isotherm involving only one sorbing species can be demonstrated in different ways: the kinetics approach, the thermodynamics approach, and the statistical mechanics approach respectively. In case of two competing adsorbed species, the competitive adsorption model is required while when a sorbed species dissociates into two distinct entities, the dissociative adsorption model need to be used.

Kinetic derivation
This section provides a kinetic derivation for a single adsorbate case. The kinetic derivation applies to gas phase adsorption. However, it has been mistakenly applied to solutions. The multiple adsorbate case is covered in the competitive adsorption sub-section.
The model assumes adsorption and desorption as being elementary processes, where the rate of adsorption rad and the rate of desorption rd are given by

where pA is the partial pressure of A over the surface, [S] is the concentration of free sites in number/m2, [Aad] is the surface concentration of A in molecules/m2 (concentration of occupied sites), and kad and kd are constants of forward adsorption reaction and backward desorption reaction in the above reactions.

At equilibrium, the rate of adsorption equals the rate of desorption. Setting rad = rd and rearranging, we obtain

The concentration of sites is given by dividing the total number of sites (S0) covering the whole surface by the area of the adsorbent (a):

We can then calculate the concentration of all sites by summing the concentration of free sites [S] and occupied sites:

Combining this with the equilibrium equation, we get

We define now the fraction of the surface sites covered with A, θA, as

This, applied to the previous equation that combined site balance and equilibrium, yields the Langmuir adsorption isotherm:

Thermodynamic derivation

In condensed phases (solutions), adsorption to a solid surface is a competitive process between the solvent (A) and the solute (B) to occupy the binding site. The thermodynamic equilibrium is described as the following:

Solvent (bound) + Solute (free) ↔ Solvent (free) + Solute (bound)

If we designate the solvent by the subscript "1" and the solute by "2", and the bound state by the superscript "s" (surface/bound) and the free state by the "b" (bulk solution / free), then the equilibrium constant can be written as a ratio between the activities of products over reactants:

For dilute solutions the activity of the solvent in bulk solution ≃1 and the activity coefficients () are also assumed to ideal on the surface. Thus,  , , and . (: activity, : mole fraction  )
Re-writing the equilibrium constant and solving for :

Note that the concentration of the solute adsorbate can be used instead of the activity coefficient. However, the equilibrium constant will no longer be dimensionless and will have units of 1/concentration units instead. The difference between the kinetic and thermodynamic derivations of the Langmuir model is that the thermodynamic uses activities as a starting point while the kinetic derivation uses rates of reaction. The thermodynamic derivation allows for the activity coefficients of adsorbates in their bound and free states to be included. The thermodynamic derivation is usually referred to as the "Langmuir-like equation".

Statistical mechanical derivation
This derivation
based on statistical mechanics was originally provided by Volmer and Mahnert in 1925. The partition function of the finite number of adsorbents adsorbed on a surface, in a canonical ensemble, is given by

where  is the partition function of a single adsorbed molecule,  is the number of adsorption sites (both occupied and unoccupied), and  is the number of adsorbed molecules which should be less than or equal to . The terms in the bracket give the total partition function of the  adsorbed molecules by taking a product of the individual partition functions (refer to Partition function of subsystems). The  factor accounts for the overcounting arising due to the indistinguishable nature of the adsorbates. The grand canonical partition function is given by

 is the chemical potential of an adsorbed molecule. As it has the form of binomial series, the summation is reduced to

where

The grand canonical potential is

based on which the average number of occupied sites is calculated

which gives the coverage

Now, invoking the condition that the system is in equilibrium, that is, the chemical potential of the adsorbed molecules is equal to that of the molecules in gas phase, we have

The chemical potential of an ideal gas is

where  is the Helmholtz free energy of an ideal gas with its partition function

 is the partition function of a single particle in the volume of  (only consider the translational freedom here).

We thus have , where we use Stirling's approximation.

Plugging  to the expression of , we have

which gives the coverage

By defining

and using the identity , finally, we have

It is plotted in the figure alongside demonstrating that the surface coverage increases quite rapidly with the partial pressure of the adsorbants, but levels off after P reaches P0.

Competitive adsorption

The previous derivations assumed that there is only one species, A, adsorbing onto the surface. This section considers the case when there are two distinct adsorbates present in the system. Consider two species A and B that compete for the same adsorption sites. The following hypotheses are made here:
 All the sites are equivalent.
 Each site can hold at most one molecule of A, or one molecule of B, but not both simultaneously.
 There are no interactions between adsorbate molecules on adjacent sites.

As derived using kinetic considerations, the equilibrium constants for both A and B are given by

and

The site balance states that the concentration of total sites [S0] is equal to the sum of free sites, sites occupied by A and sites occupied by B:

Inserting the equilibrium equations and rearranging in the same way we did for the single-species adsorption, we get similar expressions for both θA and θB:

Dissociative adsorption

The other case of special importance is when a molecule D2 dissociates into two atoms upon adsorption. Here, the following assumptions would be held to be valid:
 D2 completely dissociates to two molecules of D upon adsorption.
 The D atoms adsorb onto distinct sites on the surface of the solid and then move around and equilibrate.
 All sites are equivalent.
 Each site can hold at most one atom of D.
 There are no interactions between adsorbate molecules on adjacent sites.

Using similar kinetic considerations, we get

The 1/2 exponent on pD2 arises because one gas phase molecule produces two adsorbed species. Applying the site balance as done above,

Entropic considerations
The formation of Langmuir monolayers by adsorption onto a surface dramatically reduces the entropy of the molecular system.

To find the entropy decrease, we find the entropy of the molecule when in the adsorbed condition.

Using Stirling's approximation, we have

On the other hand, the entropy of a molecule of an ideal gas is

where  is the thermal de Broglie wavelength of the gas molecule.

Limitations of the model

The Langmuir adsorption model deviates significantly in many cases, primarily because it fails to account for the surface roughness of the adsorbent. Rough inhomogeneous surfaces have multiple site-types available for adsorption, with some parameters varying from site to site, such as the heat of adsorption. Moreover, specific surface area is a scale dependent quantity and no single true value exists for this parameter. Thus, the use of alternative probe molecules can often result in different obtained numerical values for surface area, rendering comparison problematic.

The model also ignores adsorbate/adsorbate interactions. Experimentally, there is clear evidence for adsorbate/adsorbate interactions in heat of adsorption data. There are two kinds of adsorbate/adsorbate interactions: direct interaction and indirect interaction. Direct interactions are between adjacent adsorbed molecules, which could make adsorbing near another adsorbate molecule more or less favorable and greatly affects high-coverage behavior. In indirect interactions, the adsorbate changes the surface around the adsorbed site, which in turn affects the adsorption of other adsorbate molecules nearby.

Modifications

The modifications try to account for the points mentioned in above section like surface roughness, inhomogeneity, and adsorbate-adsorbate interactions.

Two-Mechanism Langmuir-Like Equation (TMLLE)

Also known as the two site Langmuir equation. This equation describes the adsorption of one adsorbate to two or more distinct types of adsorption sites. Each binding site can be described with its own Langmuir expression as long as the adsorption at each binding site type is independent from the rest.

: total amount adsorbed at a given adsorbate concentration

: maximum capacity of site type 1

: maximum capacity of site type 2

: equilibrium (affinity) constant of site type 1

: equilibrium (affinity) constant of site type 2

: adsorbate activity in solution at equilibrium

This equation works well for adsorption of some drug molecules to activated carbon in which some adsorbate molecules interact with hydrogen bonding while others interact with a different part of the surface via hydrophobic interactions (hydrophobic effect). The equation was modified to account for the hydrophobic effect (also known as entropy-driven adsorption):

The hydrophobic effect is independent of concentration since . Therefore, the capacity of the adsorbent for hydrophobic interactions () can obtained from fitting to experimental data. The entropy-driven adsorption originates from the restriction of translational motion of bulk water molecules by the adsorbate, which is alleviated upon adsorption.

Freundlich adsorption isotherm

The Freundlich isotherm is the most important multi-site adsorption isotherm for rough surfaces.

where αF and CF are fitting parameters. This equation implies that if one makes a log-log plot of adsorption data, the data will fit a straight line. The Freundlich isotherm has two parameters while Langmuir's equations has only one: as a result, it often fits the data on rough surfaces better than the Langmuir's equations. However, the Freundlich equation is unique; consequently, if the data fit the equation, it is only likely, but not proved, that the surface is heterogeneous. The heterogeneity of the surface can be confirmed with calorimetry. Homogeneous surfaces (or heterogeneous surfaces that exhibit homogeneous adsorption (single site)) have a constant  of adsorption as a function of % sites occupied. On the other hand, heterogeneous adsorption (multi-site) have a variable  of adsorption depending on the percent of sites occupied. When the adsorbate pressure (or concentration) are low, high energy sites will be occupied; and as the pressure (or concentration) increases, the lesser energy sites will be occupied resulting in a lower  of adsorption.

A related equation is the Toth equation. Rearranging the Langmuir equation, one can obtain:

Toth modified this equation by adding two parameters, αT0 and CT0 to formulate the Toth equation:

Temkin adsorption isotherm
This isotherm takes into account indirect adsorbate-adsorbate interactions on adsorption isotherms. Temkin noted experimentally that heats of adsorption would more often decrease than increase with increasing coverage.

The heat of adsorption ΔHad is defined as:

He derived a model assuming that as the surface is loaded up with adsorbate, the heat of adsorption of all the molecules in the layer would decrease linearly with coverage due to adsorbate-adsorbate interactions:

where αT is a fitting parameter. Assuming the Langmuir Adsorption isotherm still applied to the adsorbed layer,  is expected to vary with coverage, as follows:

Langmuir's isotherm can be rearranged to this form:

Substituting the expression of the equilibrium constant and taking the natural logarithm:

BET equation

Brunauer, Emmett and Teller (BET) derived the first isotherm for multilayer adsorption. It assumes a random distribution of sites that are empty or that are covered with by one monolayer, two layers and so on, as illustrated alongside. The main equation of this model is:

where

and [A] is the total concentration of molecules on the surface, given by:

where

in which [A]0 is the number of bare sites, and [A]i is the number of surface sites covered by i molecules.

Adsorption of a binary liquid on a solid

This section describes the surface coverage when the adsorbate is in liquid phase and is a binary mixture.

For ideal both phases - no lateral interactions, homogeneous surface - the composition of a surface phase for a binary liquid system in contact with solid surface is given by a classic Everett isotherm equation (being a simple analogue of Langmuir equation), where the components are interchangeable (i.e. "1" may be exchanged to "2") without change of equation form:

where the normal definition of multi-component system is valid as follows :

By simple rearrangement, we get

This equation describes competition of components "1" and "2".

See also
 Hill equation (biochemistry)
 Michaelis–Menten kinetics (equation with the same mathematical form)
 Monod equation (equation with the same mathematical form)
 Reactions on surfaces

References

 The constitution and fundamental properties of solids and liquids. part i. solids. Irving Langmuir; J. Am. Chem. Soc. 38, 2221-95 1916

External links
 Langmuir isotherm from Queen Mary, University of London
 LMMpro, Langmuir equation-fitting software

Surface science
Materials science


Hutzel Women's Hospital is one of the eight institutions that compose the Detroit Medical Center. The hospital itself is connected to Harper University Hospital, on the midtown Detroit campus of the Medical Center. It is the only hospital in Southeast Michigan dedicated to women's care. As Michigan’s first and only hospital for women, Hutzel Women’s Hospital has been The Destination for Women’s Care since 1868.

History
Hutzel Women's Hospital is the second oldest hospital in the city of Detroit. It traces its lineage to the period right after the American Civil War when a group of seven women formed an association in 1868 to provide care for unwed mothers and their infants.

Throughout the late 19th century and early and mid-20th century, the hospital became known for its innovative care of women and children, including Detroit's first baby incubator, Michigan's first research laboratory devoted to the "study of women's diseases," and establishment of the nation's first "Mother's Milk Bureau" to ensure a supply of breast milk to infants of non-lactating mothers.

In 1965 the hospital was renamed Hutzel Women's Hospital in honor of Eleonore Hutzel, recognizing her 54 years of service as a student, employee, and trustee of the hospital. Since that time the hospital has seen its services grow to include orthopedics, ophthalmology, a pain clinic and sleep center.

Hutzel is home to the nation's only National Institutes of Health (NIH) Perinatology Research Branch.

Clinical services
Hutzel Services include: High-Risk Pregnancy Care, Maternal-Fetal Medicine, Minimally Invasive Surgery, Incontinence/Urogynecology, Long-term Birth Control, Menopause and Bariatric (Weight Loss) Surgery

Hutzel "firsts"

1898: Detroit's first infant incubator for salvaging premature babies.

1909: Michigan's first research laboratory devoted to the study of "the diseases of women."

1912: Detroit's first hospital-based social services department which ensured that the holistic view of total treatment - including follow-up - was used with all patients, regardless of their ability to pay. Establishment of the nation's first "Mother's Milk Bureau" to ensure a supply of breast milk to infants of non-lactating mothers.

1915: Establishment of the city's first hospital-based prenatal clinics.

1928: The first hospital to routinely segregate maternity patients from medical/surgical patients to prevent disease contamination.

1955: Opened the first fertility center in Detroit.

1972: The nation's first hospital to develop and use xeroradiography for the early detection of breast cancer.

1983: Began Michigan's first in vitro fertilization program.

1983: Development of the state's first reproductive genetics program.

1983: The establishment of Michigan's first hospital-based nurse midwifery program.

1984: Michigan's first successful in vitro births were born at Hutzel.

1993: Development of the world's first embryo fetoscopy procedures.

1995: The world's first successful fetal surgery to correct a right-sided diaphragmatic hernia in a fetus was performed at Hutzel.

1998: Development of infertility procedures that allow for the fertilization of the female egg with a single sperm by direct injection and then the direct re-implantation of the fertilized egg back into the female.

1999: Institution of one of the nation's first integrated programs for first trimester screening for Down syndrome and trisomy 18.

2002: The National Institute of Child Health and Human Development granted a 10-year contract to house its Perinatology Research Branch, an intramural branch of the National Institutes of Health (NIH) that conducts studies into maternal and infant health and disease, with an estimated value of $125 million over its duration.

2002: Hutzel first in US to perform the Essure procedure for women requiring permanent birth control.

2002: Hutzel Women's Hospital was granted the largest study of its kind to treat women with Polyscystic Ovarian Syndrome (PCOS) who have infertility problems.

Ranking
Hutzel Women's Hospital is listed in The Leapfrog Group’s 2008 Top Hospital list for patient quality and safety. The Leapfrog Group rankings are based on a survey conducted at 1,220 hospitals across the country.

Famous births
 Lizzo - Rapper
 Diana Ross - Singer

References

External links

 Detroit Medical Center
 Hutzel Women’s Hospital

Hospitals in Detroit
Teaching hospitals in Michigan
Midtown Detroit
Detroit Medical Center
Hospitals established in 1868
Tenet Healthcare
Women in Michigan
Women's hospitals


Mayakkam Enna () is a 2011 Indian Tamil-language psychological drama film written and directed by Selvaraghavan and produced by Gemini Film Circuit in association with Aum Productions its own banner. It stars his brother Dhanush, along with newcomer Richa Gangopadhyay, and features music scored by G. V. Prakash Kumar while the cinematography was handled by Ramji. The film revolves around an aspiring photographer and the problems he faces, causing him to fall into distress. How he manages to achieve his goals from thereafter forms the rest of the story.

The film was produced and distributed by Gemini Film Circuit, it was released on 25 November 2011 to critical acclaim but became an average hit at the box office.

Plot
Karthik Swaminathan, an introvert, referred to as 'Genius' by his friends, is a freelance photographer who aspires to become a wildlife photographer like Madhesh Krishnasamy. His friends Sunder Ramesh, Shankar, Padmini, and Vindhya  support him and his sister after the death of their parents.

One day, Sunder introduces Yamini as his girlfriend to Karthik and his friends. On their first meeting, Karthik and Yamini have a bitter experience but slowly develop a special bond. Karthik tries to stay away from Yamini since he does not want to break his friend's heart, but a sequence of events brings them closer. Eventually, Sunder's father arranges for Karthik and Yamini to be married.

After their wedding, Karthik learns that Madhesh had used a photograph that he had taken to win a national award. After this incident, he turns into a physically abusive alcoholic, and people start doubting his sanity and his mental health is somewhat affected. Yamini supports him, hoping that he will succeed one day. Days later when the residents of Karthik's house berate Karthik behind his back in front of Yamini, she gets angry and defensive and supports her husband. After watching TV where he sees Madhesh win an award for his photo, Karthik starts breaking the TV and accidentally pushes Yamini in a fit of rage. This leads to Yamini's miscarriage. Yamini returns a few days later from the hospital and stops talking to Karthik entirely. This makes Karthik come to terms with reality, and he mends his ways. He finally gets a break and becomes a professional wildlife photographer, and one of his photographs gets nominated for an International Photography Award, which he wins. On this occasion, Karthik thanks everyone for their support and Yamini for her faith in him and declares his love for her. Yamini finally relents and talks to Karthik. Then Karthik says thanks to Madhesh where the film ends.

Cast
Dhanush as Karthik Swaminathan
Richa Gangopadhyay as Yamini Karthik (voiceover by Deepa Venkat)
Sunder Ramu as Sunder Ramesh
Mathivanan Rajendran as Shankar
Pooja Devariya as Padmini
Zara Barring as Ramya
Raviprakash as Madhesh Krishnasamy
Shilpi Kiran as Vindhya
Rajiv Choudhry as Ramesh

Production

Development

Jyothika was initially approached by Selvaraghavan, to do the lead female role.Though She liked the role, she wasn't ready to accept the role as her son Dev was getting 1 year old.Later  Richa Gangopadhyay, replaced her.Selvaraghavan began the film featuring Dhanush and Richa Gangopadhyay, who had initially been signed to do another film with him. Richa began shooting for the film in Kannur in May 2011, and the film was wrapped up within three months. The title was finally changed to Mayakkam Enna from 'Idhu Maalai Nerathu Mayakkam' in August 2011, with reports suggesting that Dhanush would sport four different looks in the film. Selvaraghavan has since made it clear that the film has a totally different script from the film that had been shelved. It was said that Dhanush would be seen in various stages, as a boy just out of his teenage to an old man.

Casting
Yuvan Shankar Raja replaced G. V. Prakash Kumar as music composer in the film, with the latter reporting it was due to "money and time issues". However, in a sensational turn, G. V. Prakash Kumar was assigned again as composer after Yuvan Shankar Raja moved out of the project as he was busy with other commitments and could not give priority to Selvaraghavan, who was in rush to complete the film and move over to his next project, Vishwaroopam. On 24 May 2011, it was announced that Selvaraghavan was ousted from the project.

Music

The soundtrack, composed by G. V. Prakash Kumar in his second collaboration with Selvaraghavan (after Aayirathil Oruvan), was released on 19 September 2011 at Radio Mirchi's Chennai station. The soundtrack has received generally positive reviews. Behindwoods commented it was "intoxicating enough", giving 3.5 out of 5.

Reception

Box office
Made on a budget of ₹40 crore and produced in 80 days, the movie underwent a 50-day theatrical run ending on 10 January 2012 to become an average grosser.

Critical response
The film received positive reviews from critics and audience.

CNN-IBN wrote that Selvaraghavan had "succeeded in presenting a sensitive and engaging movie". The Times of India gave 3.5 out of 5, citing: "...with Mayakkam Enna he [Dhanush] proves why he is one of the best actors around". Deccan Chronicle gave 3.5 out of 5 and stated that it had a "fresh appeal and is straight from the heart without any clichéd frills". The New Indian Express wrote: "A sensitively crafted screenplay, deft narration, stunning vignettes and montages, and a brilliant performance by the lead pair, makes Mayakkam Enna a fascinating watch".  Deccan Herald wrote that it was "entertaining and worth a watch".

NDTV stated it was a film "with soul and worth a watch". In regard to Dhanush's performance, it wrote: "His myriad emotions elevate the movie to a great extent". The review in The Hindu says: "Selvaraghavan knows where his potential lies and has tapped it suitably." Pavithra Srinivasan of Rediff gave the film 3 out of 5 and wrote: "[It] has a brilliant first half but the film looses the steam in the second half". Sify claimed: "Simplistic story with a hard hitting impact, Mayakkam Enna will stay with you". Behindwoods rated 3.5/5 and called it "emotionally rich" and an "inebriating experience by itself". Indiaglitz cited that it does "mesmerize you and you will definitely consider watching this film more than once". Oneindia wrote that it was a "treat for youngsters".

Accolades
Edison Awards
 Best Actress – Richa Gangopadhyay
 Best Editor – Kola Bhaskar
 Best Cinematographer – Ramji

Norway Tamil Film Festival
 Best Actress – Richa Gangopadhyay
 Best Editor – Kola Bhaskar
 Best Dubbing Artiste – Deepa Venkat

References

External links

2011 films
Films scored by G. V. Prakash Kumar
Films directed by Selvaraghavan
2010s Tamil-language films
Indian romantic drama films


Karavasta Lagoon () is the largest lagoon in Albania and one of the largest adjoining the Mediterranean Sea, spanning an area of . Karavasta is part of the Divjakë Karavasta National Park and is separated from the Adriatic Sea by a large strip of sand. It sprawls across the Myzeqe coastal plain near Divjakë and some  near Lushnjë.

Name

The name is mentioned for the first time in 1297, when the people of the Albanian Principality of Mataranga of Caravastasi () attacked and robbed a ship that had stopped in the lagoon.

The Albanian name Karavasta is a loan from  karavostasi "place of anchorage". Evidently Karavasta in medieval times was navigable and served as a natural harbor for ships, and perhaps as a place for building ships.

Flora and fauna
Karavasta hosts many pine trees and small sandy islands. It is renowned for hosting the Dalmatian pelican; 6.4% of the Europe's population of the Dalmatian pelican is found in Karavasta. The lagoon falls within the Illyrian deciduous forests terrestrial ecoregion of the Palearctic Mediterranean forests, woodlands, and scrub biome. The climate is typically mediterranean.

Geomorphology
The lagoon is located inside the boundaries of Divjaka-Karavasta National Park and has been recognised as a wetland of international importance by designation under the Ramsar Convention. The lagoon has been identified as an Important Bird Area by BirdLife International, because it supports significant numbers of the populations of various bird species.

The Karavasta Lagoon is within the List of Ramsar wetlands of international importance and is part of the Divjake-Karavasta National Park.

Preservation
Since disinfection campaigns have long been halted, the area is known to have a very active mosquito season. However, in 2014, disinfection campaigns have started and a park rehabilitation project has been initiated by the national authorities. It included a hunting moratorium which revived bird-watching activities.

See also

 Divjaka-Karavasta National Park
 Geography of Albania
 Lagoons of Albania

References

Karavasta
Wetlands of Albania
Ramsar sites in Albania
Geography of Fier County
Tourist attractions in Fier County
Important Bird Areas of Albania
Albanian Adriatic Sea Coast


Langford and Ulting railway station served the village of Langford, Essex. It was opened in 1848 by the Maldon, Witham & Braintree Railway (MWBR) on a branch line from  to .

It was originally named Langford but was renamed Langford and Ulting in 1923. The station was  from Witham.

The line and station closed to passenger services in 1964 as part of the Beeching closures.

References

External links
 Langford and Ulting station on navigable 1945 O. S. map

 Webpage including 1957 photograph of the station.

Disused railway stations in Essex
Former Great Eastern Railway stations
Beeching closures in England
Railway stations in Great Britain opened in 1848
Railway stations in Great Britain closed in 1964


Maminas is a village and a former municipality in the Durrës County, western Albania. At the 2015 local government reform it became a subdivision of the municipality Shijak. The population at the 2011 census was 8868.

References

Administrative units of Shijak
Former municipalities in Durrës County
Villages in Durrës County
Populated places disestablished in 2015


The Museum Vicente Pallotti is located on Avenida Presidente Vargas, 115 in Santa Maria, Rio Grande do Sul, Brazil. It is located in the same complex Palotina College (FAPAS). Visits need to be scheduled in advance.

Rooms
The museum has many rooms, with great emphasis on the area of paleontology, with fossils of geopark of paleorrota.

Mineralogy
Zoology
Hides and other
Birds
Snakes, insects and fish
Paleontology
War material
Archeology

History
In 1935, in the District of Vale-Vêneto, José Pivetta and Valentim Zamberlan started taxidermy in the museum, which is already part of the same collection.

In 1959, due to lack of space in Vale-Vêneto, the museum transferred to the College Máximo Palotino in Santa Maria. Moreover, in 1964, Daniel Cargnin, contributing to the museum in the college, collected various objects and fossils of geopark of paleorrota. On 7 January 1965, the museum received the first fossil, excavated in the Paleontological Site Sanga of Alemoa, near the town of Santa Maria. From this date, its growth continued, thanks especially to the efforts of Daniel Cargnin and Abraão Cargnin.

During the years 1972 to 1994, the museum personnel received several donations of the community in general and collections of sites: archaeological and palaeontological. During these years, the Museum Vicente Pallotti became a large repository of objects, and for this reason, the entire collection was in precarious conditions. Then in 1994, aiming to solve the difficulties, the museum was given its first phase of reorganization that continued until 1998. In 1998, work began on the second phase of reorganization.

External links
Museu Vicente Pallotti

Museums established in 1935
Archaeological museums in Brazil
Geology museums in Brazil
Natural history museums in Brazil
Culture in Rio Grande do Sul
Museums established in 1959
Museums in Rio Grande do Sul
Fossil museums
1935 establishments in Brazil
National heritage sites of Rio Grande do Sul


Manëz or Manzë is a town and a former municipality in the Durrës County, western Albania. At the 2015 local government reform it became a subdivision of the municipality Durrës. The population at the 2011 census was 6,652.

The town is known for Camp Ashraf 3, the headquarters for the exiled Iranian political group, the People's Mujahedin of Iran (PMOI/MEK).

See also
People's Mojahedin Organization of Iran#Settlement in Albania (2016–present)

References

Administrative units of Durrës
Former municipalities in Durrës County
Towns in Albania
Populated places disestablished in 2015


The Lahitolle 95 mm cannon (Mle 1875) was a French cannon of the 19th century, developed in 1875 by the artillery commander de Lahitolle. The Lahitolle 90 mm was the first French field cannon made of steel, and one of the first to be equipped with a screw breech (issued 16 years after the British and Prussians adopted a similar system). It was adopted by the French Army in 1875 and later superseded the Reffye and de Bange 90 mm cannons. An improved version, the Lahitolle 95 mm (Mle 1888), was developed in 1888.

Coastal Artillery
A version called the Canon de 95 sur affut de Cote mle 1904 was mounted on a Vavasseur mount with a gun shield for use in coastal defenses.  The gun sat on a cradle that held the trunnioned barrel on top of a pedestal.  When the gun fired a combination of inclined rails, and hydraulic buffers returned the gun to position.

Fortress Artillery
In addition to its coastal defense role, Lahitolle 95 mm cannons were employed on pedestal mounts in France's Séré de Rivières system of fortifications.  Approximately 475 cannons were used in coastal and land fortifications.

Railway Artillery
Early in World War One, 16 coastal defense cannons were mounted on armored rail cars for use with France's armored trains.  They are believed to have been retired by 1916.

World War I
The Lahitolle 95 mm was still in use during World War I, together with the de Bange 90 mm cannon, as French industry could not keep with production requirements for the much newer Canon de 75.

World War II
The Lahitolle 95 mm was still in use in the fortifications of the Maginot line during World War II.  Mle 1904 guns captured by the Germans were given the designation 9.5cm Küstenkanone (f) and used in Germany's Atlantic Wall fortifications.

Gallery

References

External links
 1888 model at the Draguignan museum with the wheel brakes deployed

Artillery of France
World War I guns
95 mm artillery


Octave of the Holy Innocents is an album by bassist Jonas Hellborg on which he is joined by guitarist Buckethead and drummer Michael Shrieve. It was recorded at Greenpoint Studio in Brooklyn, New York, and was released by the Swedish label Day Eight Music in 1993. Hellborg later reworked the album and reissued it on his Bardo Records label.

Regarding his association with Buckethead, Hellborg stated that he "was always playing electric on everything he was doing. It was interesting to see what he could do with acoustic guitar. I like the record and what he did. It's sort of minimalist in a sense. It's definitely a clear musical statement and makes sense to me."

In the album liner notes, Hellborg asked: "Who is pure? Who is innocent? We need to protect innocence. Not only individuals' rights to be innocent but also innocence as a source of beauty, creativity and wisdom."

Reception

In a review for AllMusic, Glenn Astarita wrote: "there's no lack of excitement here, as this acoustic-based power trio generates quite a bit of momentum in concert with a few ethereally enacted dreamscapes... it's all about the sparkling chemistry that prevails throughout this wonderfully conceived and executed project! (Strongly recommended)."

Paul Acquaro of The Free Jazz Collective called the album "dark and lugubriously melodic," and stated that it "rewired parts of [his] musical listening brain."

Track listing
 "Rana and Fara" – 15:00
 "Death that Sleeps in Them" – 5:22
 "The Past is a Different Country, I Don't Live There Anymore" – 9:14
 "Child King" – 5:47
 "Kidogo" – 7:13

Credits
 Buckethead – acoustic guitar
 Jonas Hellborg – acoustic bass, keyboards
 Michael Shrieve – drums

References

1993 albums
Jonas Hellborg albums
Buckethead albums


Repere Transilvane ("Transylvanian Highlights") was a Romanian weekly literary and political magazine, issued by the Radio Transilvania. It was a bilingual publication, in Romanian, and Hungarian. The first edition was printed on May 4, 1999.

Footnotes

External links
  Új román-magyar lap Zilahon
  A romániai magyar kisebbség történeti kronológiája 1990-2003

Defunct literary magazines published in Europe
Bilingual magazines
Defunct magazines published in Romania
Hungarian-language magazines
Literary magazines published in Romania
Magazines established in 1999
Magazines disestablished in 2000
Mass media in Zalău
Magazines in Transylvania
Political magazines published in Romania
Romanian-language magazines
1999 establishments in Romania


Avoch railway station was a station on the single track branch of the Highland Railway, in north east Scotland. The line connected villages in The Black Isle peninsula to the railway network via a junction at Muir of Ord.

History

Opened by the Highland Railway in 1894, it became part of the London, Midland and Scottish Railway during the Grouping of 1923. The station then passed on to the Scottish Region of British Railways on nationalisation in 1948. It was then closed by British Railways.

Authorisation was obtained on 4 July 1890 to build a 15.75 mile (25 km) branch line from Muir of Ord to Rosemarkie; however the line never proceeded beyond Fortrose.

References

Notes

Sources

 Station on navigable O.S. map
 Vallance, H.A. (1985). The Highland Railway. 4th Extended edition: extra material by C.R. Clinker and Anthony J. Lambert. Newton Abbot: David St John Thomas. .

External links
 Avoch station on navigable O. S. map

Disused railway stations in Ross and Cromarty
Former Highland Railway stations
Railway stations in Great Britain opened in 1894
Railway stations in Great Britain closed in 1951
1894 establishments in Scotland
1951 disestablishments in Scotland
Black Isle


Ishëm is a former municipality in the Durrës County, northwestern Albania. At the 2015 local government reform it became a subdivision of the municipality Durrës. The population at the 2011 census was 5,001. Ishëm Castle is located in the municipal unit.

Famous peoples
 Ibrahim Kodra

Gallery

See
 Ishëm (river)
 Ishëm Castle
 Rodoni Castle
 Cape of Rodon
 St. Anthony Church, Durrës

References

Administrative units of Durrës
Former municipalities in Durrës County
Populated places disestablished in 2015


Adarmahān (in Greek sources given as , Adaarmanes; fl. late 6th century) was a Persian general active in the western frontier of the Sassanid Empire against the East Roman (Byzantine) forces, during the Byzantine–Sassanid War of 572–591.

Biography

Adarmahān is recorded as a marzbān (general of a frontier province, "margrave"), probably of Nisibis, by the Syriac historian John of Ephesus. He was posted at Nisibis in 573, when the Persian king, Khosrau I (r. 531–579), sent him at the head of an army to invade the Roman province of Syria. He devastated the province, sacked the city of Apamea, capturing several thousand prisoners, and defeated a small Roman force under general Magnus.

In 577, he raided the Roman province of Osrhoene, but withdrew at the approach of a strong Roman army under general Justinian. In 580, the East Roman general Maurice advanced with an army along the river Euphrates toward the Sassanid capital, Ctesiphon. In response, Adarmahan was ordered to begin operations in northern Mesopotamia (581), threatening the Roman army's supply line and forcing Maurice to stop and withdraw his army north. Adarmahan pillaged Osrhoene, and was successful in capturing its capital, Edessa. Then he marched his army toward Callinicum on the Euphrates. There, however, he was met by Maurice and his army, and suffered a minor defeat which caused him to retreat. In June of the next year (582), Adarmahan suffered a heavy defeat by Maurice near Constantina, barely escaping the field, while his co-commander Tamkhosrau was killed. Thereafter, Adarmahan disappears from history.

References

Sources

6th-century Iranian people
People of the Roman–Sasanian Wars
Sasanian governors of Nisibis
Generals of Khosrow I
Generals of Hormizd IV
Nusaybin


Sukth is a village and a former municipality in the Durrës County, western Albania. At the 2015 local government reform it became a subdivision of the municipality Durrës. The population at the 2011 census was 15,966.

The village is divided by the Erzen river is into two districts, namely in Sukth i Ri and Sukth i vjeter. Sukth is located about three kilometres north of the historic market town of Shijak. The Adriatic Sea is only seven kilometres away.

Sukth municipality consisted of Sukth, Hamallaj, Kulla, Perlat, Vadardha and Rrushkull villages. The last mayor was Sherif Fortuzi.

Sport
The local football club is FK Sukthi.

Notable people
Below are notable personalities born in Sukth or that spent most of their lives in Sukth:

Noizy, singer, rapper
Renato Arapi, football player
Elidion Mara, football player

References

Administrative units of Durrës
Former municipalities in Durrës County
Towns in Albania
Populated places disestablished in 2015


An electrical contractor is a business person or firm that performs specialized construction work related to the design, installation, and maintenance of electrical systems.
An electrical contractor is different from an electrician; an electrician is an individual tradesman and an electrical contractor is a business person or company that employs electricians. Both usually hold licenses and insurances to properly and safely operate a business, protecting the employees and home owners/business owners from insurance liabilities. These requirements vary from state to state. Electricians may work for an electrical contractor, or directly for individuals or companies.

Industry classifications
Electrical contractors are generally classified by three major types of work performed.
 "Outside" or "line" contractors are responsible for high-voltage power transmission and distribution lines. Line contractors build and maintain the infrastructure required to transport electricity generated at a power plant through a series of high-voltage lines and substations before it is used to power facilities, buildings, and homes.
 "Inside" electrical contractors provide electricity to any structure within a property's boundary lines, including outdoor lighting or substations. Under current construction specification guidelines, "inside" electrical contractors can serve as prime contractors for all electrical and cabling design, installation, and maintenance for commercial, institutional, and residential buildings. Projects also include Database Centers/Infrastructure and Pharmaceutical Work.
 "Integrated building systems" (IBS) or "Voice/Data/Video" (VDV) electrical contractors work primarily with low-voltage installations such as back-up power, climate controls, wireless networks, energy-efficient lighting, telecommunications, fiber optics, and security systems. IBS contractors are particularly skilled at integrating these system controls to work together for maximum energy efficiency and building performance.

Industry jobs
Electrical contractors employ workers in many capacities, determined by their level of training and experience. Some common jobs include:

 Apprentice Electrician — Receives on-the-job training and classroom instruction from licensed journeymen or master electricians about how to install, modify, repair, and maintain power and lighting systems. Most apprentice programs last 3 to 5 years and apprentices earn wages during this training period.
 Journeyman Electrician — Installs, modifies, repairs, and maintains power and lighting systems. Reads blueprints, terminates cable, and installs and troubleshoots control wiring from drawings. Has completed the apprentice program and holds a journeyman's license (according to state requirements) and supervises apprentices.
 Estimator — Calculates a project's duration and cost, including materials, overhead, and labor. This estimate is often submitted as a bid on a project and serves as a scheduling and budget guideline as the project proceeds.
 Project Supervisor — Oversees workforce to encourage safe and high-quality installations. Monitors progress to meet project deadlines. Submits required reports and forms.

Trade associations

United Kingdom
In the United Kingdom, the two main trade associations are the Electrical Contractors' Association, covering England, Northern Ireland and Wales, and SELECT - the Electrical Contractors' Association for Scotland. The main certification bodies are the National Inspection Council for Electrical Installation Contracting and Elecsa.

United States
The National Electrical Contractors Association (NECA) is the largest trade association in the electrical contracting industry, with about 4500 members. NECA publishes an industry magazine, and sponsors an annual convention and trade show. Independent Electrical Contractors (IEC) is another trade association for electrical contractors with 70 chapters across the U.S. They provide education and training via a U.S. Department of Labor recognized apprenticeship program.

The International Brotherhood of Electrical Workers organizes and represents over 700,000 members, and provides training and apprenticeship programs.

Safety
Electrical contractors in the United States are required to follow National Electrical Code (NEC) to ensure systems work in a safe manner. The NEC is a widely adopted model code for the installation of electrical components and systems, designed to safeguard persons and property from hazards arising from the use of electricity. While these are the default minimum requirements and guidelines, some states modify selected areas of the NEC code to suit their specific circumstances.

References

External links
National Electrical Contractors Association website

Electric power
Electrical trades
Electrical wiring


Royal Engineer tunnelling companies were specialist units of the Corps of Royal Engineers within the British Army, formed to dig attacking tunnels under enemy lines during the First World War.

The stalemate situation in the early part of the war led to the deployment of tunnel warfare. After the first German Empire attacks on 21 December 1914, through shallow tunnels underneath no man's land and exploding ten mines under the trenches of the Indian Sirhind Brigade, the British began forming suitable units. In February 1915, eight Tunnelling Companies were created and operational in Flanders from March 1915. By mid-1916, the British Army had around 25,000 trained tunnellers, mostly volunteers taken from coal mining communities. Almost twice that number of "attached infantry" worked permanently alongside the trained miners acting as 'beasts of burden'.

From the spring of 1917 the whole war became more mobile, with grand offensives at Arras, Messines and Passchendaele. There was no longer a place for a tactic that depended upon total stasis for its employment. The tactics and counter-tactics required deeper and deeper tunnelling, hence more time and more stable front lines were also required, so offensive and defensive military mining largely ceased. Underground work continued, with the tunnellers concentrating on deep dugouts for troop accommodation, a tactic used particularly in the Battle of Arras.

Background

In siege warfare, tunnelling is a long-held tactic for breaching and breaking enemy defences. The Greek historian Polybius, in his Histories, described accounts of mining during Philip V of Macedon's siege of the town of Prinassos; there is also a graphic account of mining and counter-mining at the Roman siege of Ambracia. Mining was a method used in siege warfare in ancient China from at least the Warring States (481–221 BC) period forward.

In 1215 during the First Barons' War, John, King of England laid siege to Rochester Castle. Eventually, he ordered his troops to dig a tunnel under the south tower, which they held up with pit props. After the tunnellers lit the props, the tower fell down, ending the siege even though the castle's main walls remained standing.

In 1346, Edward III of England requested that miners from the Forest of Dean, Gloucestershire accompany his expedition to France, during the first part of the Hundred Years' War between England and France.

The Corps of Royal Engineers were formed in 1717. In 1770, the Company of Soldier Artificers formed a specialist tunnelling troop in Gibraltar to dig defensive positions into the Rock.

During the Siege of Lucknow in 1857, Royal Engineers were asked to undertake counter-mining.

The use of mines filled with explosives as an offensive weapon for trench warfare was pioneered during the American Civil War, where a large mine was exploded by Union forces during the Battle of the Crater.

First World War formation

By the end of May 1915, continuous opposed trenches with no vulnerable flanks, stretched from the North Sea coast to neutral Switzerland. With both sides equally well dug-in and deploying comparable troop numbers and armaments, neither was to prove strong enough to force a decisive breakthrough. The resultant static warfare meant that tunnelling saw a brief resurgence as a military tactic. As in siege warfare, mining was possible due to the nature of the fighting. Secondly, the ground on the Western Front was a prime candidate for underground warfare. Although the British were equipped with Royal Engineers who were trained in carrying out sapping, mining and tunnelling operations, there was no core team of specialist skills.

Request and proposal

Even before it became apparent that the Germans were mining to a planned system, the commanding officer of the IV Corps, Lieutenant-General Henry Rawlinson, requested the establishment on 3 December 1914, of a special battalion to assist with mining duties.

Towards the end of 1914, the civil engineering company of Member of Parliament and British Army Major, John Norton-Griffiths, was working on sewerage renewal contracts in Liverpool and Manchester. The relatively small-bore tunnels were being driven by a manual technique known as clay-kicking. Only useful in firm clay soils, the man doing the digging sat with his back supported by a wooden frame, with his feet pointing towards the cutting face. With a spade-like tool he dug out the clay, passing the spoil over-head to one of his mates for disposal at the rear. In early December 1914, Norton-Griffiths wrote to the War Office suggesting that the technique would be useful attack, spying or for intercepting German tunnels coming in the opposite direction. He concluded by asking to be allowed to take a group of his "moles" to France where if the soil was right, they could quickly undermine enemy positions. His letter was filed.

On 20 December 1914, by digging shallow tunnels under no man's land, German sappers placed eight  mines beneath the positions of the Indian Sirhind Brigade in Givenchy-lès-la-Bassée. Following their simultaneous detonation, an infantry attack resulted in the loss of the entire company of 800 men.

Kitchener responds
Following further attacks, it was evident by January 1915 that the Germans were mining to a planned system. As the British had failed to develop suitable counter-tactics or listening devices, Field Marshal John French, commander of the British Expeditionary Force, wrote to the Secretary of State for War, Herbert Kitchener, describing the seriousness of the German mining situation. Norton-Griffiths received a telegram on 12 February 1915, instructing him to report to the War Office. On his arrival, he was shown into Kitchener's private offices, There, Kitchener showed him French's letter. Kitchener then asked Norton-Griffiths for his advice. Using a coal shovel from the room's fire grate, Norton-Griffiths sat on the floor and gave a demonstration of "clay-kicking."

Impressed but sceptical, Kitchener asked Norton-Griffiths to travel that day to France to communicate his method to the commanders there, and confirm the suitability of the Flanders soil. If positive, he would then raise a suitable battalion of "moles", as Norton-Griffiths had named his new teams, the same name as their civil engineering counterparts. Arriving with two of his employees at the GHQ Saint-Omer office of the Engineer-in-Chief (E-in-C), Brigadier George Henry Fowke, on 13 February, Norton-Griffiths gave another demonstration of "clay-kicking." A sceptical Fowke instructed his assistant, Colonel Harvey, to take Norton-Griffiths and his employees to Army and Corps headquarters on 14 February, to see what the Corps of Royal Engineers thought of the idea.

In an early public relations exercise, on 14 February, Norton-Griffiths got Colonel Harvey to stop at four headquarters – Army, Corps, Division and Brigade. At each briefing, Norton-Griffiths repeated his demonstration. On arrival at the front line, (a mile from where the first German mine had exploded the previous December), they confirmed the excellent conditions of the clay-based soil and returned to St Omer via the four headquarters to communicate their findings. The following day, the team held further meetings in St Omer, concluding with a meeting between Norton-Griffiths, Fowke and Sir John French, the C-in-C, for a personal explanation. Fowke gave his agreement to a trial to which French agreed, and the three set out a structure for what were to be called tunnelling companies, rather than Norton-Griffiths' preference for 'moles': a symbol which many of the tunnelling companies would later adopt as their unit sign.

In a meeting with Lord Kitchener on 17 February, he reported on his visit to France and the agreement of Collins and Fowke to form trial tunnelling companies. Norton-Griffiths pointed out that to deploy the units at the speed which Lord Kitchener had suggested, would require the recruitment of civilians, who could not undergo basic military training to enable their immediate deployment to the front line. Kitchener's staff were highly sceptical of the proposal, but using his carte-blanche skill to cull such skilled men from regular infantry units, Norton-Griffiths won his argument. The same day, 17 February, British sappers at Hill 60 near Ypres blew a small mine which they had taken over from the French, but without great effect. The Germans retaliated with a small mine at Zwarteleen, but were driven out of the British positions. On 21 February, however, they blew a large mine nearby, killing forty-seven men and ten officers of the 16th Lancers. In mid-March the Germans blew another large mine at Zwarteleen, creating a   deep crater and damaging their own lines in the process.

First tunnelling companies
Norton Griffiths travelled to Manchester on 18 February and closed down one of his tunnelling contracts, making 18 staff redundant. The following day the War Office gave its approval to the Royal Engineers tunnelling company scheme. On the same day, 18 formerly redundant Manchester men turned up in Chatham to be enrolled, clothed and turned into Royal Engineers. One of the most rapid acts of the First World War, men who were working underground as civilians on 17 February, were working underground on the Western Front a mere four days later. The first nine Royal Engineer Tunnelling Companies, numbers 170 to 178, were each commanded by a regular RE officer – they comprised: five officers and 269 sappers, aided by temporarily attached infantrymen as required, (which almost doubled the companies' number). Norton-Griffiths, in the rank of major, acted as a liaison officer between these units and the E-in-C's office in St Omer.

Although able to select almost any soldier he wished, as he had predicted, Norton-Griffiths was quickly forced to recruit civilians. The new recruits in these units, aged anything up to 60, did not readily conform to military discipline and Norton-Griffiths' skills as a politician and as an engineer were called on in recruiting the men he needed and integrating them into the military environment. His judgement of people was remarkably accurate, he very rarely made a mistake in selecting men for a commission. The deployment of the first eight units led to the introduction of the tunnelling method that allowed the British to dig tunnels at a rate of  per day, compared to the Germans' .

Hill 60, Ypres Salient
The first attack of the newly formed tunnelling companies of the Royal Engineers was carried out by 173rd Tunnelling Company. First deployed in the Ypres Salient with the 28th Division, the tunnelers laid six mines by 10 April 1915. These mines (together with others that were unfinished) were filled with around  of Ammonal explosives, the resulting explosions ripping the heart out of Hill 60 over a period of about 10 seconds. The effect was a mini-earthquake that split the ground under the entire hill, white flames shot  into the sky. Concrete pillboxes and soldiers occupying them came down in all directions  away. The explosion resulted in a  deep crater, with surrounding trenches sandwiched shut so fast that soldiers were crushed, still in their standing positions. The Germans all around were crying with fear. Many retreated in terror, the-then tunnel master, Otto von Füsslein, was castigated, although the position was quickly recaptured a few days later.

The action showed the importance of the necessity for a counter-offensive against German mining on the British lines. Having proven the system, Norton-Griffiths left the company and returned to London in April 1916 and his duties as an MP. He left GHQ with his rough plan of August 1915 for extensive mining on the Messines front, which formed the framework on which mines were used at the Battle of Messines two years later. He was awarded the Distinguished Service Order for his efforts, mentioned in dispatches three times and promoted to lieutenant colonel in 1916.

Expansion
The success of the Tunnelling Companies led to mining being made a separate branch of the new E-in-C's office, which was under Major-General S.R. Rice and the appointment of an Inspector of Mines at GHQ. The second group of tunnelling companies were formed from Welsh miners from the 1st and 3rd Battalions of the Monmouthshire Regiment, who were attached to the 1st Northumberland Field Company, Royal Engineers, a Territorial unit.

Twelve Tunnelling Companies were ultimately formed in 1915 and one more in 1916. A Canadian troop was formed from men on the battlefield, plus two other companies trained in Canada and then shipped to France. Three Australian and one New Zealand tunnelling companies were formed by March 1916. This resulted in 30 companies by the end of 1916, many made up of ex-miners. The establishment for a tunnelling company was set at 14 officers and 307 other ranks (ORs). Early in 1916 20 of the companies were to be raised to a higher establishment of 18 officers and 530 ORs, but none ever reached that strength; the other five remained on the original establishment. All of these companies were occupied on other underground work such as the digging of subways, saps (a narrow trench dug to approach enemy trenches), cable trenches, underground chambers for such things as signals and medical services, as well as offensive and defensive mining.

Methodology
Both sides deployed tunnelling, with the German lead quickly followed by the British follow-up. The result was a labyrinth of tunnels within a cat and mouse-like game of tunnelling, counter-tunnelling and counter tactics. As the tactics and counter tactics deployed against each other became less and less effective, the depth at which the tunnels needed to be dug became deeper and deeper and hence more dangerous. The result was a greater time to dig, resulting in a greater vulnerability to both leakage of information and tunnel collapse, and a higher loss of lives in the most hideous of circumstances: entombment, drowning, gassing or obliteration in cramped and claustrophobic galleries beneath no man's land.

Recruitment
To make the tunnels safer and quicker to deploy, the British Army enlisted experienced coal miners, many outside their nominal recruitment policy. The desperate need for skilled men saw notices requesting volunteer tunnellers posted in collieries, mineral mines and quarries across South Wales, Scotland and the Northeast of England covering Derbyshire, County Durham, Nottinghamshire and Yorkshire. In addition, specialist tin miners were also recruited from the Cornish mines mainly joining the 251st Company RE. To attract the tin miners, a per diem of six shillings a day was offered to underground miners, which was around double to that was being paid in the mines.

The mining assistants who acted as 'beasts of burden' were often made up of "Bantams" - soldiers of below average height who had been rejected from regular units because they did not meet the height requirements. Upon the declaration of war in August 1914, William Hackett applied and was turned down three times at the age of 41 by the York and Lancaster Regiment. On 25 October 1915, despite having been diagnosed with a heart condition, he was enlisted and sent for two weeks basic training at Chatham, joining 172nd Tunnelling Company.

Digging
As tunnels were vulnerable to attack, the entrances were a closely guarded secret. With electricity in short supply in the frontline, tunnellers were forced to work by candlelight. Operating in near silence to avoid detection, the tunnels were cold, cramped and often up to a foot deep in freezing water. Tunnel entrances were most often at the bottom of deep shafts. From here, using the clay-kicking technique, the tunnels were aligned and given direction by the simple use of candlelight. They were built on a slight uphill gradient of between 1:100 and 1:50 to keep them as dry as possible. This meant that they were also vulnerable to the accumulation of gas at the digging face.

A clay-kicking team typically consisted of three men: a "Kicker" who worked at the face, a "Bagger" who filled sandbags with the lumps of clay spoil, and a "Trammer" who transported the bags out of the gallery on a small, rubber-tyred trolley on rails. The trolley was also employed to bring timber in on the return journey. If the tunnel was long, the trammer was given extra assistants to speed the exit of spoil and intake of timber. The team was responsible for its own safety, and would insert a 'sett' of wooden supports every . As no nails or screws could be used due to noise, the 'setts' (consisting of a sole, two legs and a cap), were sawn with a rebated step, which, once trimmed into the clay, would expand with the absorbed water into a solid structure.

Working conditions
Working in cold, cramped conditions, miners worked in 6- or 12-hour rotating shifts. Miners were prone to illness, with high rates of trench foot and bad food disease, while fatigue compounded the situation, creating a high mortality rate. The miners also had to cope with difficult circumstances when they entered the mining tunnels. Often the tunnels were dark, small and flooded with water. Tunnellers were billeted quite a long way back from the front line, while a regular Royal Navy-style rum ration was issued to keep out the cold. Natural gases and gases given off as a result of explosions could ignite, poison or asphyxiate. The major problem gas for tunnellers was carbon monoxide, given off by all projectiles from shells to rifle bullets.

With the use of experienced miners, came the use of "miners friends" in the form of mice and later small birds, such as canaries. With a high metabolic rate, they were readily susceptible to gas, and issued to the Tunnelling Companies as an official item. When gas was present, their unconsciousness would alert miners to the need to evacuate. Although many animals died, others would recover on the surface, with at least one company keeping a record of the gassings so that their creatures did not have to endure more than three instances before being pensioned off to an aviary. The role of the miners friends are honoured on the Scottish National War Memorial in Edinburgh. In extensive tunnelling systems, air-tight doors were introduced to control air flows.

Mine rescue
Such was the reliance on mining during the early stages of the war, that eventually mining-related casualties became so great that the War Office decided something had to be done about mine rescue. The skilled mining volunteers were particularly hard to replace. In one six-week period, one tunnelling company had 16 men killed; 48 sent to hospital; and 86 minor cases treated at the shaft head and returned to company billets. Another company suffered 12 men killed by gas; 28 sent to hospital in one month; 60 minor cases were retained with the unit. The affected mining units put out an urgent call for appropriate rescue equipment. Captain D Dale Logan was appointed advisor to GHQ in September 1915 on all matters connected with the health of the specially enlisted Tunnelling Companies.

In June 1915, Lance Corporal Arthur B. Clifford was made solely responsible for mine safety training. Sent to the front to train 3000 mine-rescue troops in a month, there were only 36 sets of 'PROTO' breathing equipment available in the whole of the United Kingdom. Clifford was based with the Royal Engineers at Strazeele, with a sub-station at Berguette. This became the first Army Mine-Rescue School. Clifford was awarded the Meritorious Service Medal in 1917 for what he had achieved.

From July 1916, under Logan's new organisation, the second Army Mine-Rescue School was established at Armentières. This allowed the British to deploy a system of mines rescue, where no mining shaft was further than  from a rescue station. Named after the kit they employed, Proto-men were hand-picked experienced miners, selected for coolness under pressure. Two men were on duty at all times, with additional access to 10 electric miners lamps, six canaries, four mobile cages, one saw, one hand axe, three life-lines, two mine stretchers, one trench stretcher, one Primus stove, two tins of café au lait, six hot water bottles and six blankets.

Underground fighting
As a result of so much mining activity by both sides, detection and breakthrough into each other's tunnelling systems occurred frequently. The result was often the deployment of the emergency camouflet, a pre-prepared charge which was always ready in the British and Allied forces sectors when tunnelling was taking place. Vicious hand-to-hand fighting in the dark with picks, shovels and wood used as weapons might also take place. Although all miners were trained to use rifles, the restrictions of tunnel construction and the conditions of the tunnels where the miners had to operate often meant they could not be used. If the opposing side were unsuccessful in repelling an attack, then enemy tunnels could be used for short periods to observe enemy tunnelling activity and direction.

Counter-mining

Listening

Early tunnelling required a great deal of improvisation, as equipment was in short supply. This made tunnels shallow, the noise of digging being detectable using simple devices in the trenches, even amongst the gun-fire. In the trenches, soldiers found that driving a stick into the ground and holding the other end between their teeth enabled them to feel any underground vibration. Another method involved sinking a water-filled oil drum into the floor of the trench, with lookout soldiers taking turns to lower an ear into the water to listen for vibrations. Improvised methods later included Water Board inspector short-sticks, each with a single vibrating wire-type earphone attached, or using filled French water-bottles laid flat on their sides in pairs, so they could be listened-to through medical stethoscopes.

Underground, within the tunnelling operations, side-shaft listening posts were deployed and manned by soldiers whose job entailed listening for indications that the enemy was tunnelling. Initially using just manual methods, the British were eventually equipped with the Geophone, which could detect noises up to  away. Employing two Geophones, a listener was able to ascertain the direction of hostile activity by moving the sensors until sound levels were equal in both ears. A compass bearing was then taken. When gauging distance only, both earpieces were plugged into a single sensor; this was a skill only gained by experience. Deploying listeners in different tunnels in triangulation techniques, by the end of 1916 the scale of British tunnelling warfare had expanded to such an extent that there were not enough listeners to man every post; central listening stations were devised. Working electronically like a telephone exchange, the signals from up to 36 remote sensors (Tele-geophones and Seismomicrophones) could be distinguished and logged by just two men.

Underground tactics

The tunnellers developed counter tactics, which both sides deployed. The first was the use of large mines placed in one's own tunnels – some actually dug towards enemy noise to create damage – which when exploded would create fissures and cracks in the ground, making the ground either unsuitable for tunnelling or destroying existing tunnels and works. A small device, called the camouflet, created a localised underground chamber designed not to break the surface and form craters, but to destroy a strictly limited area of underground territory – and its occupants. The second tactic, deployed when the enemy tunnel was too close to your existing works or trenches, was the deployment of rod-fed torpedo shaped camouflet charges. Effectively land mines on the end of long iron sticks, the technique was a defensive tactic against an immediate threat. Towards the end of the tunnel war, forces also deployed mines at greater depths, which, coupled with the use of listening devices, could be exploded away from friendly trenches as a defensive measure.

British advantages
The British tunnellers had three advantages over their German counterparts, the Pioniere:

Firstly, the British used clay-kicking which was a virtually silent method of tunnelling. The Germans did not know of this technique, having not used it in their pre-war civil engineering, and thus used mattocks (a type of pick-axe) and other loud tools throughout the war. This made their tunnels more vulnerable to detection and attack.

Secondly, the use of clay-kicking made the British four times as fast at tunnel digging as their German counterparts.

Thirdly, British positions were most often located in low-lying areas, while German positions tended to be more elevated. Although this made the British more vulnerable to shelling, it also meant that British tunnellers had less of the soft quicksand-like 'Kemmel Sands' (known to the Germans as Schwimmsande), an integral component of the geological make-up of the ridges around Ypres, to penetrate. While the bottom blue clay layer was virtually flat, as was the Kemmel Sands that sat on top of it, there was a dry strata which varied above this which created the geographical contours. This varying dry strata increased pressure on the Kemmel Sands, which unable to egress water below them, made them wet and unstable. When punctured, the Kemmel Sands would often "spout" under pressure, both water and solid material. Difficult to dig through and keep the mining wooden structure stable, the Germans, assuming that the British had the same instability problem, dug few tunnels until 1916. The British found an engineering solution by creating a metal tube through the Kemmel Sands. Sunk either through its own weight or by the use of hydraulic jacks, once the blue clay layer was hit, the tunnelling could again resume under wooden supports. In autumn of 1915, 172nd Tunnelling Company at St Eloi  managed to sink shafts through the sandy clay at a depth of  down to dry blue clay at a depth of , which was ideal for tunneling,  from where they continued to drive galleries towards the German lines at a depth of . This constituted a major achievement in mining technique and gave the Royal Engineers a significant advantage over their German counterparts.

The British used tube shafts from May 1915, a full year before the Germans, who when they did start to use metal and concrete tunnels, had lost the strategic advantage and were digging purely for defensive purposes.

Operations

Tunnelling companies were not popular amongst the ordinary troops. Knowing such a unit was nearby made them nervous:
 Danger from above the ground (from the enemy)
 Danger from below the ground (from their own and enemy tunnelling companies)
 If the enemy knew a tunnelling company was in the area, it made the trench troops a more likely artillery target. This was further emphasised as the war developed with both sides using larger and larger mines, often deployed ever-closer to their own trenches. These were more likely not to be detonated on time, or if they did, shower debris over their own trenches and advancing troops, causing increased casualties.

The first British mine to be detonated was by the 173rd Tunnelling Company at Hill 60 (10 April 1915). Mines were also used at The Bluff, St Eloi (six on 27 March 1916), the Battle of Aubers Ridge (May 1915); Hooge, Givenchy, Cuinchy and the Battle of Loos (September 1915).

In June 1916, during the height of the underground war on the Western Front, British tunnellers fired 101 mines or camouflets, while German tunnellers fired 126 mines or camouflets. This amounts to a total of 227 mine explosions in one month – one detonation every three hours. The last British deep mine of the First World War was fired by 251st Tunnelling Company at Givenchy (10 August 1917).

Hooge and Mont Sorrel

The small village of Hooge in Flanders belonged to one of the easternmost sectors of the Ypres Salient, which made it the site of intense and sustained fighting between German and Allied forces. From 1914 the front line of the Salient ran through the Hooge area. There was almost constant fighting in the area over the next three years, and Hooge changed hands a number of times. The château at Hooge was used as the British divisional headquarters for the area for some time; several senior officers from the 1st and 2nd Divisions were killed when the Château de Hooge was shelled on 31 October 1914.
German forces attacked the château between 24 May and 3 June 1915 and despite the detonation of a mine by the 175th Tunnelling Company (operating with the 3rd Division) on 19 July, leaving a massive crater, took control of the château and the surrounding area on 30 July 1915. The château and the crater (craters being strategically important in relatively flat countryside), were taken by the British 6th Division on 9 August. It was reclaimed by the Germans on 16 June 1916 and retaken by the British on 31 July 1917 when the 8th Division managed to advance past it by about a mile. The Germans retook the site in April 1918 as part of the Spring Offensive but were expelled from the area by the British on 28 September as the offensive faltered. The chateau was completely destroyed along with the entire village; several large craters were blown over the course of the 1917 fighting.

Battle of the Somme

In the Somme sector of the Western Front, local but very fierce underground fighting had taken place in the winter of 1914 and spring of 1915 at La Boisselle, Fricourt, Bois Français and Carnoy. As part of the Allied preparations for the Battle of the Somme (1 July – 18 November 1916), the tunnelling companies of the Royal Engineers made two major contributions to the opening attack: Firstly, they placed a number of mines beneath the German front lines, laid deep in the chalk and overcharged to throw up high lips for screening and to give advantage to the attackers when (or if) they captured them. Secondly, they prepared a series of shallow Russian saps from the British front line into no man's land, which would be opened at Zero Hour and allow the infantry to attack the German positions from a comparatively short distance. Thirdly, members of the 183rd company also dug a tunnel for a Livens Large Gallery Flame Projector, one of 4 installed in preparation for the battle.

For the start of the battle on 1 July 1916, the Royal Engineers planned to fire a group of eight large and eleven small mines along the Somme front line. The most important of them were beneath Hawthorn Ridge Redoubt at Beaumont-Hamel, beneath a German field fortification known as Schwabenhöhe just south of La Boisselle and three in a sector named The Tambour near Fricourt. The Hawthorn Ridge Redoubt mine, which consisted of  of explosives, was the first to be detonated. This led to the successful filming of the explosion by British cinematographer Geoffrey Malins, who was filming the 29th Division's attack on that day. Despite their colossal size, the largest of the mines fired on 1 July 1916 failed to help sufficiently neutralise the German defences. At La Boisselle, the ruined village was meant to fall in 20 minutes, but by the end of the first day of the battle, it had not been taken while the III Corps divisions had lost more than . At Mash Valley, the attackers lost 5,100 men before noon, and at Sausage Valley near the crater of the Lochnagar mine, there were over 6,000 casualties – the highest concentration on the entire battlefield. The III Corps' 34th Division suffered the worst losses of any unit that day.

Battle of Messines

In January 1917, General Sir Herbert Plumer, gave orders for a series of mines to be placed under the German lines in preparation for the Battle of Messines.

These were not the first mines in the Ypres Salient. From 1915, British engineers started digging, but it was not until the winter of 1916 when they were joined by Canadian, Australian and New Zealand engineers, that mass tunnelling started under the German trenches. At St Eloi, six mines were detonated on 27 March 1916. At Hill 60, a gallery was started in summer 1915 and known as Berlin Tunnel. The 1st Australian Tunnelling Company took over mining operations at Hill 60 in November 1916, led in part by Captain Oliver Woodward. Twenty-six deep mines were eventually dug in preparation of the Battle of Messines in 1917, some up to  long and up to  deep, altogether containing 600 tonnes of ammonal explosive. To solve the problem of wet soil, the tunnels were dug in the layer of "blue clay", 80–120 feet (25–30 m) below the surface. The galleries dug in order to lay these mines eventually totalled over  in length, and had been constructed in the face of tenacious German counter-mining. On several occasions, German tunnellers were within yards of large British mine "chambers." The mine at Petite Douve Farm was discovered by the Germans on 24 August 1916 and destroyed by a counter-mine.

With doubts about the reliability of the system (some mines had been lying underground for over a year), soldiers waiting in the trenches had been warned that they could not depend absolutely on the mines working as planned, so their orders were to leave their trenches and attack whether the mines exploded or not. The explosion of the mines took place at 03:10 on 7 June 1917. Approximately 10,000 German troops were killed when the mines were simultaneously detonated, creating  large craters and an explosion so loud it was heard by British Prime Minister David Lloyd George  in his study in 10 Downing Street in London. There is even a report of an insomniac student hearing it in University College Dublin. The evening before the attack, General Sir Charles Harington remarked to his staff, "Gentlemen, we may not make history tomorrow, but we shall certainly change the geography."

The largest of the mines at Messines was at St Eloi, dug by the 1st Canadian Tunnelling Company, consisting of  of explosive. This allowed the capture of St Eloi by the British 41st Division. Another large mine was at Spanbroekmolen. Found and counter-mined by the Germans a few weeks before the attack, the British were forced to dig a second entrance tunnel into the already prepared explosive chamber, (which consisted of 41 tons of ammonal explosive  below ground), to reconnect the detonation wires. Although tested fully just a few hours before the attack, officers used torch batteries to prove the circuits. As instructed, soldiers of the 36th (Ulster) Division had already left their trenches and begun to move across No-Man's Land when the mine exploded a few seconds late, leading to some being killed by falling debris. They are buried in Lone Tree Cemetery nearby. The "Lone Tree Crater" formed by the blast was approximately  in diameter, and  deep.

Four mines close to Ploegsteert Wood (Birdcage 1–4) were not exploded as they were outside the attack area. The British intended to dismantle the remaining mines, but the Third Battle of Ypres delayed operations, after the Germans overran the group headquarters their location was lost. On 17 July 1955, a lightning strike set-off one of the remaining mines. There were no human casualties, but one cow was killed and some local property damage was sustained. The remaining mines with several tonnes of high explosive are still buried under the Belgian countryside. A memorial to the Australian mining troops killed at Hill 60 during the course of the war was later placed at the site.

Battle of Vimy Ridge

Between October 1915 and April 1917 an estimated 150 French, British and German charges were fired in this  sector of the Western Front. The tunnelling companies of the Royal Engineers progressively took over from the French between February and May 1916. The units active around Vimy were the 172nd, 175th, 176th, 182nd, 184th, 185th and 255th Tunnelling Companies.

The British soon discovered that German tunnelling companies had taken advantage of the relative calm on the surface to build an extensive network of tunnels and deep mines from which they could attack French positions. The Royal Engineers immediately deployed tunnelling companies of the Royal Engineers along the front to combat the German mining operations. In response to increased British mining, German artillery and trench mortar fire intensified in early May 1916. After September 1916, when the Royal Engineers had constructed defensive galleries along most of the front line at Vimy, offensive mining largely ceased. By 1917, 19 crater groups existed along this section of the Western Front, each with several large craters. The British gallery network beneath Vimy Ridge grew to a length of .

Before the Battle of Vimy Ridge (9–12 April 1917), the British tunnelling companies secretly laid a series of explosive charges under German positions in an effort to destroy surface fortifications before the assault. The original plan had called for 17 mines and 9 Wombat charges to support the infantry attack, of which 13 (possibly 14) mines and 8 Wombat charges were eventually laid. In order to assess the consequences of infantry having to advance across cratered ground after a mining attack, officers from the Canadian Corps visited La Boisselle and Fricourt where the mines on the first day of the Somme had been blown. Their reports and the experience of the Canadians at St Eloi in April 1916 – where mines had so altered and damaged the landscape as to render occupation of the mine craters by the infantry all but impossible –, led to the decision to remove offensive mining from the central sector allocated to the Canadian Corps at Vimy Ridge. In the end, two mines were blown before the attack, while three mines and two Wombat charges were fired to support the attack, including those forming a northern flank.

End of mining operations

From Spring 1917 the whole war became more mobile, with grand offensives at the Battles of Arras, Messines and Passchendaele, there was no longer a place for a tactic that depended upon total immobility for its employment. As the tactics and counter-tactics required deeper and deeper tunnelling, (hence more time and requiring more stable front lines), offensive and defensive military mining largely ceased. The last mine fired by the British in the First World War was near Givenchy on 10 August 1917.

Even after mine warfare had stopped, underground work continued, with the tunnellers concentrating on deep dugouts for troop accommodation, safe from the larger shells being deployed.

According to the original trench maps, hospitals, mess rooms, chapels, kitchens, workshops, blacksmiths, as well as bedrooms where exhausted soldiers could rest, were hewn from the blue-clay and stone. Connected by corridors measuring 6 ft 6in high by 4 ft wide, they were fitted with water pumps which, when the troops left within weeks of the war ending, were slowly submerged. The developments at Hill 60 housed 3,000 men, those near Hooge 1,000. The Vampire dugout, a brigade headquarters built by 171st Tunnelling Company near Zonnebeke, was captured and occupied by the Germans in their Spring Offensive in 1918, before being retaken in September. The level of activity can be gauged by the fact that during 1917 and 1918, more people lived underground in the Ypres area than reside in the town today. About 180 dugout sites have been located in the Ypres Salient and in the 1990s some of them were entered, at least in part.

Battle of Arras

In preparation for the Battle of Arras in 1917, the Royal Engineers had been working underground from October 1916, constructing tunnels for the troops. The Arras region is chalky and therefore easily excavated; under Arras itself there is a vast network of caverns (called the boves), which consist of underground quarries, galleries and sewage tunnels. The engineers devised a plan to add new tunnels to this network so that troops could arrive at the battlefield in secrecy and in safety. The scale of this undertaking was enormous: in one sector alone four Tunnel Companies (of 500 men each) worked around the clock in 18-hour shifts for two months.

The British attack plan was well developed, drawing on the lessons of the Somme and Verdun in the previous year. Rather than attacking on an extended front, the full weight of artillery fire would be concentrated on a relatively narrow stretch of . The barrage was planned to last about a week at all points on the line, with a much longer and heavier bombardment at Vimy to weaken its strong defences. During the assault, the troops would advance in open formation, with units leapfrogging each other in order to allow them time to consolidate and regroup. Before the action could be undertaken, a great deal of preparation was required, much of it innovative.

To assist the attack, the Royal Engineers constructed  of tunnels, graded as subways (foot traffic only); tramways (with rails for hand-drawn trollies for taking ammunition to the line and bringing casualties back); and railways (a light railway system). Just before the assault the tunnel system had grown big enough to conceal 24,000 men, with electric lighting provided by its own small powerhouse, as well as kitchens, latrines and a medical centre with a fully equipped operating theatre. The bulk of the work was done by New Zealanders, including Māori and Pacific Islanders from the New Zealand (Māori) Pioneer Battalion, and Bantams from the mining towns of Northern England.

Assault tunnels were also dug, stopping a few yards short of the German line, ready to be blown open by explosives on Zero-Day. In addition to this, conventional mines were dug under the front lines, ready to be blown immediately before the assault. Many were never detonated for fear that they would churn up the ground too much. In the meantime, German sappers were actively conducting their own underground operations, seeking out Allied tunnels to assault and counter-mine. Of the New Zealand Tunnelling Company alone, 41 died and 151 were wounded as a result of German counter-mining.

Today, most of the tunnels and trenches are off-limits to the public for reasons of safety. A 250-metre portion of the Grange Subway at Vimy Ridge is open to the public from May to November and the Wellington tunnel was opened to the public as the Carrière Wellington museum in March 2008.

Second Battle of Passchendaele

In preparation for the Second Battle of Passchendaele, as early as the 17 October, assault units were given all available details about the German defences in their respective sectors, in order to facilitate early planning. Intelligence officers and artillery observers worked jointly in observation posts recording newly built German fortifications as well as those that had previously escaped notice, permitting the artillery to take necessary action before the offensive. To improve the logistical movement of artillery and supplies an extensive programme of road building was started. Ten field companies, seven tunnelling companies, four army troop companies and nine battalions were put to work repairing or extending existing plank roads. From the middle of October until the end of the offensive, a total of  of double plank road and more than  of heavy tram line was constructed in the Canadian Corps area. Brigadier General Edward Morrison, commanding the artillery, also secured permission to use the roads to the rear for withdrawing disabled guns for repair.

Remains and memorials

Many of the largest craters have been left, often too large to fill-in, even today. The largest crater on the Western Front, the Lochnagar Crater, had been left for 50 years, but it had begun to be used by motorbikers and as a rubbish dump. Privately purchased in 1979, it is now a recognized 1914–1918 historic battlefield site.

Around Ypres, some large craters remain near Hooge, as do several of the craters created by the mines in the Battle of Messines, including those at St Eloi (created by a charge of  of ammonal), Maedelstede Farm (created by a charge of  of ammonal), and at Spanbroekmolen (created by a charge of  ammonal). When detonated on 7 June 1917, the blast at Spanbroekmolen formed the "Lone Tree Crater" with a diameter of  and a depth of . The crater was acquired in 1929 by the Toc H foundation in Poperinge and is today recognized as the Pool of Peace memorial.

In a little square just outside Wijtschate church stands the 'Memorial to the British Miners of World War One' who were engaged in underground war beneath the Messines Ridge. The bronze statue depicts a young miner in a kneeling position, working with a pickaxe (photo).

The Royal Engineers grave at Railway Wood on the Bellewaerde Ridge near Zillebeke, about 4 kilometres east of Ypres, marks the spot where eight Royal Engineers of the 177th Tunnelling Company and four attached infantrymen were killed between November 1915 and August 1917 whilst tunneling under the hill near Hooge. Their bodies were left in situ, beneath the hill on which the memorial now stands. One of the twelve men commemorated here is Second Lieutenant Charles Geoffrey Boothby (1894–1916), whose wartime letters to his girlfriend were published in 2005.

On a small square in the centre of Sint-Elooi stands the 'Monument to the St Eloi Tunnellers' which was unveiled on 11 November 2001. The brick plinth bears transparent plaques with details of the mining activities by 172nd Tunnelling Company and an extract from the poem Trenches: St Eloi by the war poet T.E. Hulme (1883–1917). There is a flagpole with the British flag next to it, and in 2003 an artillery gun was added to the memorial.

In Givenchy-lès-la-Bassée, the 'Tunnellers Memorial' commemorates the action on 26 June 1916 for which William Hackett of 254th Tunnelling Company was awarded the Victoria Cross. The memorial stands at the site of the Shaftesbury Shaft and the Red Dragon Crater. Its dimensions,  high and  wide, mirror the standard interior proportions of mine galleries constructed by the tunnelling companies in the Flanders clays. The memorial was designed by Peter Barton and unveiled on 19 June 2010.

Awards

Victoria Cross
At least three men who served with the Tunnelling Companies were awarded the Victoria Cross, two of whom were members of tunneling units at the time of their VC action:
 Captain William Henry Johnston (1879–1915) won the Victoria Cross during the Race to the Sea in September 1914. He subsequently transferred to the Tunnelling Companies and in early 1915 he commanded 172nd Tunnelling Company at St Eloi in the Ypres Salient. His Victoria Cross is displayed at the Royal Engineers Museum, Chatham, Kent.
 Sapper William Hackett (1873–1916) of 254th Tunnelling Company, who was awarded the Victoria Cross posthumously for helping his fellow miners when a tunnel collapsed at Givenchy-lès-la-Bassée, France, on 26 June 1916. His medal is held by the Royal Engineers Museum. Hackett is commemorated on the Ploegsteert Memorial to the Missing and at the Tunnellers Memorial at Givenchy.
 Captain Coulson Norman Mitchell (1889–1978) of 1st Canadian Tunnelling Company operating with the 4th Canadian Division. He was awarded the Victoria Cross for preventing the demolition of bridges on the Canal de L'Escaut, north-east of Cambrai on 8–9 October 1918. His medal is held by the Canadian Military Engineers Museum, CFB Gagetown, New Brunswick.

Distinguished Conduct Medal
 Sam Gloade was awarded the Distinguished Conduct Medal for his service in the tunnelling company of the 6th Field Company and Battalion, Royal Canadian Engineers.
 Cpl George Smith 86462 176th Tunnelling Company was awarded a Distinguished Conduct Medal in 1916.

Units
During the First World War, the tunnelling companies of the Royal Engineers comprised the following British and Commonwealth components:
 170th Tunnelling Company (known for its role at the Hohenzollern Redoubt)
 171st Tunnelling Company (known for creating the Vampire dugout)
 172nd Tunnelling Company
 173rd Tunnelling Company (the first Royal Engineer tunnelling company to fire mines on 17 April 1915)
 174th Tunnelling Company
 175th Tunnelling Company (known for its role at Hooge in 1915)
 176th Tunnelling Company
 177th Tunnelling Company (known for its role at Railway Wood)
 178th Tunnelling Company
 179th Tunnelling Company (known for creating the Lochnagar mine)
 180th Tunnelling Company
 181st Tunnelling Company
 182nd Tunnelling Company
 183rd Tunnelling Company (known for using the LLG Flame Projector in the Battle of the Somme)
 184th Tunnelling Company
 185th Tunnelling Company
 250th Tunnelling Company
 251st Tunnelling Company (known for firing the last British mine in First World War on 10 August 1917)
 252nd Tunnelling Company (known for creating the Hawthorn Ridge mine)
 253rd Tunnelling Company
 254th Tunnelling Company (known as the unit of Sapper William Hackett VC)
 255th Tunnelling Company
 256th Tunnelling Company
 257th Tunnelling Company
 258th Tunnelling Company
 VIII Corps Mining Company (later merged into the 254th Tunnelling Company)
 1st Canadian Tunnelling Company (known for creating the deep mine at St Eloi)
 2nd Canadian Tunnelling Company
 3rd Canadian Tunnelling Company
 New Zealand Tunnelling Company (known for its role at Carrière Wellington)
 Australian Mining Corps (split into the 4 companies below after May 1916:)
 Australian Electrical Mechanical Boring and Mining Company
 1st Australian Tunnelling Company (portrayed in the film Beneath Hill 60)
 2nd Australian Tunnelling Company
 3rd Australian Tunnelling Company

See also
 1st Anzac Entrenching Battalion
 Birdsong, a 1993 novel by Sebastian Faulks, was adapted in 2012 as a two-part television drama directed by Philip Martin. The novel tells the story of an officer who fights alongside a tunneller at Messines and draws heavily on the experiences of the tunnelling companies of the Royal Engineers.
 Beneath Hill 60 a 2010 Australian war film, directed by Jeremy Sims and written by David Roach, tells the story of the 1st Australian Tunnelling Company. The screenplay is based on an account of the ordeal written by Captain Oliver Woodward, who is portrayed by Brendan Cowell.

Notes

References

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 Graham E. Watson & Richard A. Rinaldi, The Corps of Royal Engineers: Organization and Units 1889–2018, Tiger Lily Books, 2018, .

Further reading

External links

 List of tunnelling companies of the Royal Engineers, with short unit histories
 'Born Fighters: Who were the Tunnellers?' Conference paper by Simon Jones.
 La Boisselle Study Group and La Boisselle Project

Military units and formations of the British Army in World War I
Units of the Royal Engineers
Tunnel warfare in World War I