Methods of Working Bedded Deposits Underground

The method of working (or method of mining) includes a definite sequence and organization of development work of a deposit, its openings and its face work in certain geological conditions. It depends on the mining plan and machines and develops with their improvements. A rational method of working should satisfy the following requirements in any particular conditions: 1) safety of the man; 2) maximum output of mineral; 3) minimum development work (per 1,000 tons output); 4) minimum production cost and 5) minimum losses of mineral.

Notwithstanding the considerable number of mining methods in existence, they can be reduced to the following main types: 1. Methods of working with long faces (continuous mining); 2. Methods of working with short faces (room-and-pillar). The characteristic feature of the continuous mining is the absence of any development openings made in advance of production faces. The main advantage of long continuous faces is that they yield more mineral. Besides, they allow the maximum use of combines (shearers), cutting machines, powered supports and conveyers. The longwall method permits an almost 100 per cent recovery of mineral instead of 50 to 80 per cent obtainable in room-and-pillar methods.

The basic principle of room-and-pillar method is that rooms from 4 to 12 meters wide (usually 6-7) are driven from the entries, each room is separated from each other by a rib pillar. Rib pillars are recovered or robbed after the rooms are excavated. The main disadvantage of shortwall work is a considerable loss of mineral and the difficulty of ventilation. In working bedded deposits methods of mining mentioned above may be used either with stowing or with caving.

In Russia, Germany (the Ruhr coal-field), France and Belgium nearly all the faces are now long ones. In Britain longwall faces predominate.

The USA, Canada, Australia and to some extent India are developing shortwall faces and creating the machines for them. In these countries shortwall faces are widely used.

In Russia the thick seams are taken out to full thickness up to 4.5 m thick if they are steep, and up to 3.5 m thick if they are gently sloping or inclined. In the Kuznetsk coal-field long faces are worked to the dip with ashield protection, using a method proposed by N.Chinakal. In shield mining coal is delivered to the lower working by gravity so that additional haulage is not required.

It should also be noted that in Russia hydraulic mining is widely used as it is one of the most economic and advantageous methods of coal getting. New hydraulic mines are coming into use in a number of coal-fields. Hydraulic mining is developing in other countries as well.

The aim of hydraulic mining is to remove coal by the monitors (or giants) which win coal and transport it hydraulically from the place of work right to the surface. It is quite obvious that the choice of the method of mining will primarily depend on the depth and the shape and the general type of the deposit.

1.Укажите, какие предложения соответствуют содержанию текста. Подтвердите свои ответы фактами из текста.

1. A definite sequence and organization of development work is called mining.

2. Mining methods in existence can be reduced to the two main types.

3. The depth and the shape of the deposit influence the choice of the method of working.

4. As is known, in Belgium all the faces are short now, in Great Britain they amount to 84 per cent.

5. In Australian collieries shortwall faces are widely used.

6. The room-and-pillar method is characterized by the absence of any development openings.

7. High-capacity monitors win coal and transport it hydraulically right to the surface.

2.Ответьте на следующие вопросы:

1. What factors does mining depend on?

2. What is mining?

3. What are the most important factors which affect the choice of the method of working?

4. Do short faces or long faces predominate in Russia? What can you say about the Ruhr coal-field?

5. Is Canada developing shortwall faces or longwall faces?

6. What are the main disadvantages of shortwall faces?

7. What are the two main methods of working?

8. What is the main advantage of long continuous faces?

9. What methods of mining long faces do you know?

10. What method of mining is characterized by the absence of development openings?

3.    а) Найдите в правой колонке русские эквиваленты следующих слов в сочетаний слов:

1.    development face      а) сплошная система разработки

2.    great losses            б) выемка целиков

3.    shield method of mining   в) подготовительный забой

4.    continuous mining г) большие потери

5.    longwall advancing to the dip      д) удовлетворять требованиям

6.    the room-and-pillar method of mining     e) зависеть от геологических условий

7.    to open up a deposit ж) выемка лавами прямым ходом по падению

8.    pillar mining          з) щитовая система разработки

9.    to satisfy the requirements                       и) вскрывать месторождение

10.  to depend upon the geological conditions к) камерно-столбовая система разработки

б) Найдите в правой колонке английские эквиваленты следующих слов и сочетаний слов:

1.    включать (в себя)                               a) safety

2.    выемка лавами обратным ходом        б) annual output

3.    достигать 50%                                         в) to involve

4.    превышать 60%                                      г) to propose a new method of mining

5.    безопасность                                           д) long wall retreating

6.    годовая добыча                                       е) in connection with difficulties

7.    основной недостаток системы разработки     ж) to exceed 60 per cent

8.    под-этаж                                              з) notwithstanding (in spite of)

9.    крутопадающий пласт                      и) to reach 50 per cent

10.  щитовая система разработки                 к) the main disadvantage of the method of mining

11.  предложить новый способ разработки л) sublevel

12.  в связи с трудностями                       м) the shield method of mining 

13.  несмотря на                                             н) open up a deposit

14.  вскрывать месторождение                о) steep seam

ВАРИАНТ 9

break v (broke, broken) отбивать (уголь или породу), обрушивать кровлю; разбивать; ломать; л отбойка, обрушение; break outотбивать, производить выемку

(руды .или породы); расширять забой; breakageл разрыхление, дробление

drill - n бур; .перфоратор; бурильный молоток; сверло; v бурить; car ~ буровая тележка; mounted~ перфоратор на колонке; колонковый бурильный молоток; drilling -n бурение

dump-n отвал (породы); склад угля; опрокид; external~ внешний отвал; internal~ внутренний отвал; v сваливать (в отвал); разгружать; отваливать; опрокидывать (вагонетку); dumperопрокид; самосвал; отвалообразователь; dumpingл опрокидывание; опорожнение; опрокид; syn tip

environment -n окружение; окружающая обстановка/среда

explode - v взрывать, подрывать; explosion- n взрыв; explosive -n взрывчатое вещество; а взрывчатый

friable - а рыхлый; хрупкий; рассыпчатый; слабый (о кровле)

handle - v перегружать; доставлять; транспортировать; управлять машиной; n ручка; рукоять; скоба; handling- n подача; погрузка; перекидка, доставка; транспортировка; обращение с машиной

heap - v наваливать; нагребать; n породный отвал, терриконик; syn spoil ~, waste ~

hydraulicklng - n гидродобыча; гидромеханизированная разработка

load - v нагружать, грузить, наваливать; n груз; нагрузка; loader -n погрузочная машина, навалочная машина, перегружатель; грузчик; cutter-loader -комбайн, комбинированная горная машина

lorry- n грузовик; платформа; syn truck

mention - v упоминать

overcasting - n перелопачивание (породы)

pump- n насос; gravel~ песковый насос; sludge~ шламовый насос; v качать; накачивать; откачивать

reclamation -n восстановление; осушение; извлечение крепи; ~ of landвосстановление участка (после открытых работ)

sidecastiag- n внешнее отвалообразование

site- n участок, место; building~ строительная площадка

slice- n слой; slicing -n выемка слоями, разработка слоями

strip- v производить вскрышные работы; разрабатывать; очищать (лаву); вынимать породу или руду; n полоса; stripper -n забойщик; вскрышной экскаватор; stripping -n открытая разработка, открытые горные работы; вскрыша; вскрытие наносов

unit - n агрегат; установка; устройство; прибор; узел; секция; деталь; машина; механизм;единица измерения; участок

washery- n углемойка; рудомойка; моечный цех

to attract smb's attentionпривлекать чье-л. внимание

Open-cast Mining

Minerals at shallow depths are extracted by open-cast mining which is cheaper than underground mining. Open-cast mining consists in removing the overburden, and other strata that lie above mineral or fuel deposits to recover them.

Opencasts or open-pit mines are in fact quarries for getting coal or metalliferous minerals. In the USA opencasts are called strip mines (strip pits).

All the surface excavations, waste heaps and equipment needed for extracting mineral in the open form an independent mining

In opencasts the excavation is by horizontal slices corresponding to the type of mineral or overburden in slice. You can see the benches (or slices). A bench is a thickness of rock or mineral which is separately broken or excavated. Other open workings are called trenches, which are long, narrow, shallow exploratory workings.

The whole production process in opencasts can be divided into the following basic stages: 1) preparing the site to be worked; 2) dewatering it and preventing inflows of water to the site; 3) providing access (entry) to the deposit by the necessary permanent investment; 4) removal of overburden (stripping); 5) mineral excavation.

Stripping the overburden and mineral production include breaking rock or mineral, transporting it and loading it.

Minerals can often be dug directly by earth-moving equipment, while to break hard rocks it is necessary to use explosives.

Modern methods of working opencasts involve the use of mechanical plants or hydraulicking. The basic units of a mechanical plant are excavators, car drills or other mounted drills, and various mechanical handling equipment whereas the basic units of hydraulicking are monitors, pumps such as sludge pumps or gravel pumps. Hydraulicking can be used in soft or friable ground.

Transport operations involve the removal of waste rock or mineral, the latter being transported to coal washeries, ore concentration plants, to power stations, or to a railway station. Waste rock is removed to a spoil heap or dump (tip) either outside the deposit or in an extracted area, these being called external or internal dumps, respectively.

The transport used in opencasts are rail cars, large lorries, and conveyers. Sometimes the overburden is stripped and dumped by excavators without other transport, in overcasting or sidecasting.

Mineral is usually unloaded at specially equipped permanent stations. Waste rock is dumped at various points which are moved as the work develops.

Summing up, mention should be made of the fact that last decades have seen a marked trend towards open-cast operations. Large near-surface (though usually low-grade) deposits offer the possibility of achieving greater outputs. There can be little doubt that the cost per ton of ore mined by underground methods is generally higher than that for open-cast mining.

At the same time it is necessary to say that although efforts are made to develop mine sites in harmony with the environment, extraction methods produce some disturbances on the Earth's surface which reduce its economic value. In recent years Russia and other countries have developed national programmes for environmental protection. The aim of such programmes applicable to the mining industry is to control and protect natural resources and regulate reclamation and landscape restoration.

1.Укажите, какие предложения соответствуют содержанию текста. Подтвердите свои ответы фактами из текста.

1. An opencast is a long, shallow, narrow exploratory working.

2. Explosives are used for excavating hard rocks.

3. Monitors, different types of pumps and other handling equipment are the basic units used in open-cast operations.

4. Waste rock is always removed to a spoil heap outside the deposit.

5. Large near-surface, usually low-grade deposits are extracted by the open-cast method.

6. Open-cast mining has all the advantages of low-cost production.

2.Ответьте на следующие вопросы:

1. What deposits can be extracted by the open-cast method?

2. What is called an opencast?

3. What is the difference between a trench and an opencast?

4. Is the removal of overburden the first operation in open-cast mining?

5. In what case is it necessary to use explosives to break mineral?

6. Is hydraulicking used only in open-cast mining?

7.What equipment is used in hydraulicking?

8. What transport systems are used in opencasts?

9. Where is waste rock dumped?

10. What is the main advantage of open-cast mining?

3. а) Найдите в правой колонке русские эквиваленты следующих слов и сочетаний слов:

1.    to consume energy

2.    friable roof

3.    waste heap (spoil heap)

4.    sludge and gravel pumps

5.    automatic dumper

6.    mounted drill

7.    explosives

8.    overcasting

9.    slicing method

10.  not to mention ...

а)    автоматический опрокид

б)    не говоря о (чём-л.)

в)    перфоратор на колонке

г)    слоевая система разработки

д)    слабая кровля

е)    потреблять энергию

ж)   отвал, террикон

з)    песковый и шламовый насосы

и)   взрывчатые вещества

к)    перелопачивание

б) Найдите в правой колонке английские эквиваленты следующих слов и сочетаний слов:

1.    участок (место)

2.    внешнее отвалообразование

3.    открытая разработка, вскрыша

4.    агрегат (установка)

5.    углемойка

6.    вскрыша; покрывающие породы

7.    гидродобыча

8.    грузовик

9.    привлекать чье-л. внимание

10.  восстановление ландшафта

а)    washery

б)    overburden

в)    site

г)    sidecasting

д)    lorry (truck)

с)    to attract smb's attention

ж)   landscape restoration

з)    unit

и)   stripping

к)    hydraulicking

ВАРИАНТ 10

backhoe- n обратная лопата

blast- n взрыв; v взрывать; дуть; продувать; blasting- n взрывание; взрывные работы; взрывная отбойка

block out- v нарезать залежь на блоки; нарезать столбы

clearing- n выравнивание почвы; планировка грунта

crash- v дробить; разрушать; обрушать(ся)

earth-mover- n землеройное оборудование; syn excavator

excavator- n экскаватор; bucket-wheel- роторный экскаватор; multi-bucket ~многочерпаковый экскаватор; single-bucket- одночерпаковый экскаватор

grab -n грейфер, ковш, черпак; экскаватор; v захватывать;

grabbing -погрузка грейфером; захватывание

hoist -n подъемное установка (машина); подъемник; лебедка; v поднимать; hoistingшахтный подъем

plough -n струг

power shovel- n механическая лопата; экскаватор типа механической лопаты

range -n колебание в определенных пределах

rate- n норма; скорость, темп; коэффициент; степень; разрез; сорт; мощность; расход (воды)

remote- а отдаленный; ~ controlдистанционное управление

result- v (in) приводить (к); иметь своим результатом; (from) следовать (из), происходить в результате

safety- n безопасность; техника безопасности

slope- n забой, сплошной забой, очистной забой; v очищать забой, вынимать породу, уголь; syn face; slopingочистные работы; очистная выемка; open slopingвыемка с открытым забоем; shrinkage slopingвыемка системой с магазинированием (руды)

support- v крепить; поддерживать; подпирать; n стойка; опора; поддержание; крепление; syn timbering; powered roof- механизированная крепь; self-advancing powered roof- передвижная механизированная крепь

Ore Mining

As has already been said mining is a branch of industry which deals with the recovery of valuable minerals from the interior of the Earth.

When minerals occur so that they can be worked at a profit, they are called ore deposits. Economic minerals are those which are of economic importance and include both metallic (ore minerals) and non- metallic minerals such as building materials (sand, stone, etc.).

In choosing the methods of working ore deposits one must take into consideration the following main factors: 1) the shape of the deposit; 2) the dimensions of the deposit in thickness, along the strike and down the dip; 3) the type of ore and the distribution of metal in the ore body.

The shape of the ore deposit affects the mining method. Besides, the contact of the deposit with the country rock is of great importance.

According to their angle of dip the deposits are divided into gently sloping (up to 25), inclined (25-45) and steep deposits (45-90). The thickness of ore deposits also varies. They may be very thin (from 0.7-0.8 m to 20 m) and extremely thick (more than 20 m).

One must say that a rational method of mining ensures the following: 1) safety; 2) minimum cost of production; 3) minimum losses of ore; 4) rate of extraction.

In metal mining as well as in mining bedded deposits preliminary activities (before mining) involve prospecting and exploration required to locate, characterize and prove a potential ore body.

After exploration has provided information on the shape and size of a deposit and its general geological characteristics, site development for mining begins. Mine development depends largely upon the kind of ore body and the mining method to be applied. As a rule mine development work involves development drilling; access road construction; clearing and grubbing; adit, slope or shaft development; overburden removal, construction of facilities such as concentration (dressing, processing) plants, etc. The different type of equipment required range from small, simple units such as backhoes and dump trucks to earth-movers, draglines and power shovels.

Mining operations begin with excavation work (blasting or separating portions of rock from the solid mass), loading, hauling and hoisting of the rock to the surface and supporting mine workings.

Generally speaking, the working of an ore deposit involves opening up, development, blocking out and sloping operations, the basic sloping methods in use now being open sloping, room and pillar mining, shrinkage sloping, block caving and others.

After ores are mined or dredged, they are usually processed (crushed, concentrated or dried).

Extraction processes can be done by underground or open-cast mining. The main trend has been toward low-cost open-cast mining.

1. Укажите, какие предложения соответствуют содержанию текста. Подтвердите свои ответы фактами из текста.

1.    Ore deposits may be called economically workable natural concentrations of minerals.

2.    It is quite enough to take into consideration the shape of the deposit for choosing its method of working.

3.    The thickness of ore deposits is a constant value.

4.    As a rule exploration provides information for mining.

5.    Equipment of various types and capacities is readily available for rock excavation and it includes power shovels, backhoes, draglines, bucket wheel excavators, etc.

6.    After mining or dredging ores are usually processed, crushed or dried.

2.    Ответьте на следующие вопросы:

1.    What minerals do we usually call economic?

2.    Is the type of ore the only factor which the engineer takes into consideration in choosing the methods of working ore deposits?

3.    What does a rational method of mining guarantee?

4.    What does before mining activity include?

5.    What processes does development work involve?

6.    What basic sloping methods are in use now?

7.    What are the main methods of working bedded deposits?

8.    Is underground or open-cast mining preferable now? Why?

9.    Can you give a few examples of the largest enterprises producing ores in the country?

3.    Найдите в правой колонке русские эквиваленты следующих слов и сочетаний слов:

1.    block caving                      а) породный отвал, терриконик

2.    crushing and diving          б) открытые горные работы, вскрыша

3.    power shovel                     в) блоковое (этажное) оборудование

4.    grabbing                            г) дробление и сушка

5.    to range (from ... to)          д) врубо-погрузочная машина, горный комбайн

6.    remote control                               e) колебаться (в определенных пределах)

7.    shrinkage sloping              ж) погрузка грейфером

8.    waste heap                        з) дистанционное управление

9.    cutter-loader                      и) выемка системой с магазинированием

10.  overcasting and side-casting к) механическая лопата, экскаватор

11.  stripping operations           л) перелопачивание и внешнее отвалообразование