Mine (layer)

See also: Mine

A mine is a material layer (for example of Or, coal, Cuivre, Diamant S, Fer, salt, uranium, etc). It can be with open sky or underground . The distinction between mine and career is due to the nature of extracted material (strategic or invaluable for the mine, of less value for the career); in France, it is the mining Code which defines that. In France, there were very many mines in almost all the areas. The coal layers are in the Nord-Pas-de-Calais (wide-area network of underground galleries of the world), in Lorraine, in the Massif Central, in Provence and in South-west (example: Carmaux) but also Saint-Etienne. The Russia has also many layers of coal in north (example: Donbass). The the United Kingdom has as for him important coal layer in north (example: Highland), in the Wales and with Manchester.

History

The exploitation of the basement probably dates from prehistory where one dug in chalk of the wells of several meters for the research of best flints.

The first constructions in stone were a probable origin with the first (career S, and agriculture with the Marnière S): it was necessary to dig the ground to extract from the stone having a sufficient quality to build. and certain stones are cut more easily coldly extracted before hardening then.

While digging in-depth, one reached a layer of rock not degraded by the microfaune and flora of the ground, or the roots of trees (a “vein”), then one dug horizontally to extract the rock from this layer (the layer according to the geological folds). These wells and corridors could be then used to be protected from the aggressions.

Techniques of exploitation of the mines

The exploitation of the mines poses many problems, and thus utilizes of many fields of the Science S. This is why in the majority of the countries created for themselves specific schools engineers, the schools of the mines.

The coal mines are organized by stages from which one exploits the layers. Each minor digs a layer to extract from it the coal which one then charges in Berlines. This work is very difficult because it is necessary to dig in order not to make break down the gallery, in addition to that, it reigns there a choking heat, because there is almost no air which circulates. The only means found to create a ventilation was to build two wells at least. The first is used for the rise and the descent of the minors and the rise of coal. The other is used only for ventilation.

By going up a ton of coal, one extracts seven tons from by-products which one evacuates on the Terril S.

Prospection

Earthwork

  • Geophysical

  • Resistance of the materials

Well and galleries

There exist various cases of figure to reach the layer to exploit and allow the evacuation of the products. If the layer is relatively horizontal (in flat vein) and if the layer of dead ground is not too thick, one will be able to exploit with open sky (see Ci below).

If the layer levels in a broken zone, for example hills overhanging a valley, one will be able to reach and exploit the layer by level galleries (through benches to see Ci below) emerging with hillside. It is, for example the case in the iron-bearing basin of Lorraine for the mines of Hussigny Godbrange, Charles Ferdinand or Kraemer.

On the other hand, if the layer does not level at all or under good conditions it does not level is necessary to dig (one says to sink) wells in order to reach it. It is the most expensive solution for the exploitation and the least profitable, it is also the majority of the cases. The two solutions can also combine (case of the mines of Mure or the iron mine of Soumont).

The case of the iron mine of St Rémy on Orne in Normandy is interesting since part of the layer is with the top of the square of the mine. The majority of the products however are descended to the lower part from the level from the well, rolled to the well to be gone up on the level it square to be treated there, solution less expensive than an exit with hillside in a poor zone on the way and means of evacuation.

The well serves the various stages of working, each level is called a receipt or fixing.

  • galleries and through benches

One distinguishes the galleries from through benches. The galleries are used directly for the exploitation of the layer. In general to exploit a layer one digs a gallery of the highest head and the gallery basic lowest. The layer is cut out in panels between these two galleries and delimited by transverse galleries uniting them. These transverse galleries make it possible to reach the coal face but also to organize the ventilation, i.e. the air circulation in work. The basic gallery also allows the evacuation of the broken products (the releasing) towards the rolling which will then take them along towards the winding shaft. The galleries can be cut in the exploited product (coal, ore) in general or with the rock on both sides of the layer. The gallery of rolling determines the level of the pit-bottom. The whole of work which allows the delimitation of a panel call the preliminary works. They are of course fundamental.

Through benches are almost always dug with the rock; they allow the connection between the wells and the deposit worked (gallery of rolling). Indeed in general the wells are dark not in the layer but outside in the rock. A well dug in coal for example, involves a trading loss since it will be necessary to maintain around the well not exploited a zone known as pillar of safety or investison (such pillars are obligatory under the inhabited areas, the roads, the railroads…).

The same reasoning applies to the worked mines with hillside. In this case them through benches emerge directly at the day with side of the slope. Since the catastrophe of Courrières, it there obligation to have at least two outlets at the day (2 wells or 1 well and 1 outlet with hillside for example).

To connect the various levels of exploitation between them (one also speaks about stage) the link can be made either by the well, or by a bore-hole or still by tilted plan. One calls bore-hole an interior well not emerging at the day connecting two levels. The tilted plan is a gallery or through benches more often inclined and generally provided with a winch in order to hoist the trucks or with a belt conveyer.

  • Supporting

Mining methods

  • general Principles

  • Exploitation of the coal
  • Exploitation of the slickenside lodgings
  • Exploitation of the sedimentary lodgings
  • Exploitation with open sky

Rolling

What rolling? It is the transport of the products (coal, ore but also the sterile one since the coal face (or more exactly since the point of arrival of the system of releasing of the building sites) until the lower receipt of the winding shaft, then possibly, since the receipt higher of the well than the workshops of treatment. The transport of the products, in the industrialized mines, is carried out in buckets (or trucks) of capacity varied according to the exploitations (of 500 liters to 25.000 liters) trails with arm in the not mechanized exploitations, by a horse (or ass or mule) then by power trolleys, electric, compressed air, gasoline or diesel. They are in general narrow gauge railways lower 1 m from broad. Rolling is a fundamental factor in the exploitation of a mine, it indeed conditions, with the well, the capacity of extraction.

  • the driving force

  • rolling stock

The extraction

Before passing to the industrial exploitation sousterraine, the areas minères knew an artisanal exploitation of veins levelling the ground. It was about an exploitation with open sky known under the name of cayat, cayaudery in the accused areas. It is to be noticed that although the old mine fields very have many streets of the cayat, the direction of the expression was lost.

  • the cables

  • apparatuses of extraction

  • the transport of the personnel
“the cage”. Inside, eighty men are put. Hands on the shoulders of the guy of in-face, it is necessary to hold balance when it plunges at the bottom, shaken like a subway train. But this does not relate to the whole of the French wells. Last technologies (well Yvon Morandat de Gardanne in Provence) were so advanced that a descent with more 1000m of depth did not produce any effect on the men. The cage could contain 132 people and no vibration was made feel.

The Pumping out

  • drainage

  • the pumps

Ventilation - ventilation

  • Atmosphere of the mines: importance of the effective fight against the dust level to prevent the Silicosis,
  • Ventilation of the mines against the accumulation of CO, CO2, methane, firedamp.
  • the ventilators pulsate or extract from the air.
  • Certaines designs of the networks of well facilitates the air circulation
  • ventilation is often a critical problem in the artisanal or illegal underground galleries.
The minors formerly carried a canary out of cage, which when he would die or gave signs of suffocation that was the sign had to be gone up.

Lighting

The study of lighting is of only one secondary interest in the mines of firedamp or dust.
  • Lighting with naked fire :
    • since antiquity, the minors lit thanks to tallow candles. The minors used them either on candlesticks of iron, or attached to the head by means of a leather belt of.
    • the Romans also made use of metal or terra cotta oil lamps, lamps lighting than the candles. Lamp Turnip.
    • the lighting power of acetylene was used as of the XIXe century. However like all the lamps with naked fire, its use was reserved for the metal mines and the underground careers. Lamp Draper.
  • Éclairage of safety by portable lamps
    • the need for a lighting of safety in the flammable atmospheres of the mines (firedamp, dust) proved to be necessary following many accidents.
    • the oldest process was imagined in Whitehaven in 1760. It is about a wheel with flint by release of showers of sparks.
    • It is with Humphry Davy and George Stephenson that we owe the concept of the lamps of safety: a metal sieve with very tight meshs prevents the propagation of a flame of the interior towards the outside of the lamp.
    • Ultérieurement the lamps were equipped initially with glass then of a sheet armor. The mineral oil being substituted for oil, one adapted to the lamps an internal system of relighting.
    • In addition to the Davy lamp, let us quote: the Clanny lamp, the Mueseler lamp, the Marsaut lamp and the Wolf lamp. Each one marking a new stage in the technical evolution of the apparatus. Many other lamps are connected with these first: the lamp Grinds (1894), the lamp Fumat (1903), the lamp Mulkay, the lamp Müller with system of magnetic closing, the lamp Cuvelier-Catrice with water seal, the lamp Demeure, the lamp Seippel, the Koch lamp.
  • Flashlights portable
    • the first portable primary pile flashlights startups in 1862 was far from answering all the safety requirements.
    • lamps with accumulator and liquid electrolyte: models of Edison, Pitkin, Swan, Bréguet, Pollak, Stella, of Mallet-Parent.
    • the accumulator lamps and immobilized electrolyte have the advantage of resisting the accidental inversions. The Süssmann lamp, the lamp max, the lamp Coat, the lamp Lux

Demolition - Extraction of the ore

  • Demolition with the hand, Work with the pickaxe, the crowbar

  • Demolition with the explosive.
  • mechanical Perforation - Work with the power pick.
  • mechanical Demolition
the passage of the Coal cutter (the extracting machine coal).
  • Demolition with the " rabot" (tool tractor drawn by chains and electrical motors equipped with interchangeable edges which tore off coal over a variable length m in Provence in the building sites of the walking support type. Its depth of atttaque in coal seam varied according to the friability of the ore.

  • System of the mobile stay.

Pneumatic (transmission of energy without risk of spark:)

  • pneumatic Demolition - By injection of compressed air with high pressure in a perforated steel tube, introduced into the borehole. This technique, rather exceptional, at summer employed in certain coal exploitations known as " gras" with the beginning of the year 1960.

Shots

  • Firedamp explosion

  • Dust explosion
  • Precautionary measures

Various accidents

  • Instantaneous outburst of Firedamp, or " blow of grisou"

  • Dust explosion caused by the firedamp explosion. It is about the accident known in the mine fields under the name of coal dust.
  • Fires
  • Ines-rush of water
  • Crumblings
  • D.I. : instantaneous outbursts of firedamp or sometimes of acid.

Rescue

  • Breathing apparatuses

  • Organization for rescue

Mines with open sky

to make

End of the exploitation of the coal mines

in France

The French State gradually disengaged coal exploitation. The profitability of the exploitation of the Houille indeed underwent, since the years 1960, a constant fall under the double effect of the diversification of the sources of energy and the competition of country profiting from very favorable conditions of operating. The signature of the coal Pact, in 1994, thus involved the closing of the last French production sites:

  • Gard: in 2001, the mine of Ales (Carboniferous of basin of the Center and South - CENTER-MIDI AREA) and reconversion of the basin.

  • the Moselle: Forbach and Merlebach.

  • Isere: Walls It.

  • Lorraine: the April 23rd 2004, the seat of Creutzwald (Collieries of the Lorraine coalfields - LORRAINE AREA) ceased its activity. In order to rehabilitate the site, the head-frames of wells 3 and 4 will be shaved, the concreted wells, the drowned galleries.

Following the stop of the exploitation, Charbonnages de France, its mission having become without object, advances towards a liquidation announced for on December 31st, 2007.

In parallel, a request for concession at summer presented to the public authorities, by private investors, within the framework of the opening of a new site in Nievre.

in Belgium

In Belgium, the decision of closing of the coal mines was made in two stages, the first in the years 1960, which led to the stop of the mines hennuyères while in 1986, the Minister for Finance Mark Eyskens (CVP) declared that the closing of last five coal mining of Limbourg (Kempense steenkolenmijnen - KS) would save much money

The disaffection of the mines

The mines whose exploitation is stopped affect the environment: they modify the landscape (careers, Terril S, industrial waste lands…) and the structure of the ground (depressions of ground, gullying…)

Mines in the literature

  • French Literature

  • foreign Literature
    • Richard Llewellyn: That it was green my valley , Editions Jeheber, 1947
    • Archibald Joseph Cronin: the Citadel , 1937
    • Tawni O' Dell: the Time of anger , Paris, Belfond Editions, 2001
    • Tawni O' Dell: Return to Coal Run , Paris, Belfond Editions, 2004. On this work, an article in the review of social sciences “EspacesTemps.net”: Pierre Schill, Coal Run, mining city of Pennsylvania, fragment of America

See too

External bonds

  • History of the lamps of mine and the lamps of safety
  • HiMAT, a Field of Special Research (SFB) interdisciplinary on the mining activities in the Alps
  • to visit the photo gallery of the mine of the Wood of Cazier with Marcinelle

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