Workings Sentence Examples
Chalk, from which blanc de Troyes is manufactured, and clay are abundant; and there are peat workings and quarries of building-stone and limestone.
Indeed, as one of the acutest and most sympathetic of his critics has remarked, the deep and settled grudge he has betrayed towards every form of Christian belief, in all the writings of his maturity, may be taken as evidence that he had at one time experienced in his own person at least some of the painful workings of a positive faith.
The workings of this Will are irrational primarily, but, as in its evolution it becomes more rationalized and understands the whole meaning of the Weltschmerz, it ultimately reaches the point at which the desire for existence is gone.
Henceforward it was to be the serious study of the workings of nature in producing the beings we see around us from beings more or less unlike them, that had existed in bygone ages and had been the parents of a varied and varying offspring - our fellow-creatures of to-day.
Mining is carried on only to a small extent for arsenic, although there are traces of former more extensive workings for other metals.
Evidences of ancient workings remain near Holguin and Gibara, and it is possible that some of these workings are still exploitable.
The most promising deposits and the most important workings are in Matanzas and Santa Clara provinces.
Here are kept very complete and curious documents of the Inquisition, showing all its workings from the 15th to the 19th century.
A tax of 10% is levied on the annual net produce of all gold workings (proclamation of 1902) and the government takes 60% of the profits on diamond mines.
Potgieter and some companions followed the trail of Trichard's party as far as the Zoutpansberg, where they were shown gold workings by the natives and saw rings of gold made by native workmen.
AdvertisementThe term 1 is not limited to underground operations, but includes also surface excavations, as in placer mining and open-air workings of coal and ore deposits by methods similar to quarrying, and boring operations for oil, natural gas or brine.
Information of this sort obtained by surface exploration is often as conclusive as similar information obtained from underground workings.
Either may be used for drainage of the mine workings, in which case it becomes an adit.
Drifts and inclined shafts following the deposit may prove difficult of maintenance when the workings become large and settlement of the overlying strata begins.
In the systematic mining of larger deposits, the simplest plan consists in mining large areas by means of numerous working-places under the protection of pillars of mineral left for the purpose, and later mining these pillars systematically, allowing the overlying rock beds to fall and fill the abandoned workings.
AdvertisementThe shrinkage of the rock-filling and the settlement of the workings /, Yan be greatly lessened by the use of hard rock with a minimum of fine stuff; but even so the advantage lies with the American system of timbering.
The cost of filling has been greatly reduced by the system of flushing culm, sand, gravel and similar material, through pipes leading from the surface into mine workings.
Opposed to the motive force producing the air current is the frictional resistance developed in passing through the mine workings.
So far as possible, vitiated air is led directly to the shaft instead of passing through other workings; for example, mine stables when used are placed near the upcast shaft and ventilated by an independent split of the ventilating current.
In addition mining operations are subject to interruption and added expense from explosions, mine fires, flooding, and the caving-in of the workings.
AdvertisementWhen direct attack is no longer practicable, it is possible to extinguish the fire by sealing the mine workings, and exhausting the supply of oxygen.
The mass of water falling down the shaft is converted into spray, which is carried by the force of the fall long distances into the workings.
Mine fires may sometimes be reached by bore-holes sunk for the purpose from the surface, and the burning workings below filled by flushing with culm and water.
The mine workings may also be flooded Flooding of by large bodies of underground water.
In such cases preliminary surveys should be made to determine the thickness of rock over the proposed workings.
AdvertisementIn Great Britain the law requires that the workings shall be protected by 120 ft.
The caving in of mine workings results from the excavation of large areas supported upon pillars of insufficient size.
While the mine workings are small the overlying rocks support themselves of and the full pressure does not come upon the mine Caving p i llars.
While abundant warning of the caving-in of the workings is thus given in advance it may happen that men are unexpectedly imprisoned by the closing of the main passage ways.
Traces of ancient workings were found in several places, but the ores did not contain gold in paying quantities.
These and the ancient copper workings were investigated by Burton in 1877.
It is not often remembered that William possessed an experience of the workings of representative government in Holland, which was remarkably similar to that in England.
It is the centre of a large gold-field consisting of quartz ranges, with some alluvial deposits, and many of the mines are deep-level workings.
From the district of Yukon (Klondike, &c.) £2,800,000 was obtained in 1899, wholly from alluvial workings, but the progress made since has been slower than was expected by sanguine people.
Alaska appeared in the list of gold-producing countries in 1886, and gradually increased its annual output until 1897, when the country attracted much attention with a production valued at over £500,000; the opening up of new workings has increased this figure immensely, from about £1,400,000 in 1901 to £3,006,500 in 1905.
In Rhodesia, the country lying north of the Transvaal, where gold occurs in well-defined quartzveins, there is unquestionable evidence of extensive ancient workings.
The gold production of Russia has been remarkably constant, averaging £4,899,262 per annum; the gold is derived chiefly from placer workings in Siberia.
In workings on a larger scale, where the supply of water is abundant, as in California, sluices were generally employed.
In a modified degree the same is true of the Indian fields; large supplies are unworked, but in several districts, especially about Raniganj and elsewhere in Bengal, workings are fully developed.
In South America coal is known in Venezuela, Colombia, Peru, northern Chile, Brazil (chiefly in the south), and Argentina (Parana, the extreme south of Patagonia, and Tierra del Fuego), but in no country are the workings extensive.
Africa is apparently the continent poorest in coal, though valuable workings have been developed at various points in British South Africa, e.g.
The opening and laying out, or, as it is generally called, "winning," of new collieries is rarely Prelimin- undertaken without a ary trial preliminary examination of coal= of the character of the workings.
The actual coal measure strata, consisting mainly of shales and clays, are generally impervious to water, but when strata of a permeable character are sunk through, such as the magnesian limestone of the north of England, the Permian sandstones of the central counties, or the chalk and greensand in the north of France and Westphalia, special methods are required in order to pass the water-bearing beds, and to protect the shaft and workings from the influx of water subsequently.
The use of two independent connexions - whether separate pits or sections of the same pit, between the surface and the workings - is necessary for the service of the ventilation, fresh air from the surface being carried down one, known as the " downcast," while the foul or return air of the mine rises through the other or " upcast " pit back to the surface.
In the latter case, which represents the most approved practice, the sinking is usually placed about the centre of the ground, so that the workings may radiate in every direction from the pit bottom, with the view of employing the greatest number of hands to advantage.
Where properties are much divided, it is always necessary to maintain a thick barrier of unwrought coal between the boundary of the mine and the neighbouring workings, especially if the latter are to the dip. If a prominent line of fault crosses the area it may usually be a convenient division of the fields into sections or districts.
The first process in laying out the workings consists in driving a gallery on the level along the course of the coal seam, which is known as a " dip head level," and a lower parallel one, in which the water collects, known as a " lodgment level."
These pillars are left for the support of the roof as the workings advance, so as to keep the mine open and free from waste.
The character of such workings is very irregular in plan, and as the ventilation is attended with considerable difficulty, it is now becoming generally superseded by more improved methods.
Where the whole of the coal is removed at once there is less chance of surface damage, when the mines are deep, than with pillar workings.
The working of very thick seams presents certain special peculiarities, owing to the difficulties of supporting the roof in the excavated portions, and supplying fresh air to the workings.
In France and Germany the method of filling the space left by the removal of the coal with waste rock, quarried underground or sent down from the surface, which was originally used in connexion with the working of thick inclined seams by the method of horizontal slices, is now largely extended to long-wall workings on thin seams, and in Westphalia is made compulsory where workings extend below surface buildings, and safety pillars of unwrought coal are found to be insufficient.
The material for filling may be the waste from earlier workings stored in the spoil banks at the surface; where there are blast furnaces in the neighbourhood, granulated slag mixed with earth affords excellent packing.
In some anthracite collieries in America the small coal or culm and other waste are washed into the exhausted workings by water which gives a compact mass filling the excavation when the water has drained away.
In securing the roof and sides of coal workings, malleable iron and steel are now used to some extent instead of timber, although the consumption of the latter material is extremely large.
By reason of their intermittent action they are only suited for use in driving galleries or in pillar-and-stall workings.
This type has been greatly improved and now is the most popular machine in Great Britain, especially in long-wall workings.
The capacity of the trams varies with the size of the workings and the shaft.
In a large colliery where the shafts are situated near the centre of the field, and the workings extend on all sides, both to the dip and rise, the drawing roads for the coal may be of three different kinds - (r) levels driven at right angles to the dip, suitable for horse roads, (2) rise ways, known as jinny roads, jig-brows, or up-brows, which, when of sufficient slope, may be used as self-acting planes, i.e.
In dip workings the tail rope is often made to work a pump connected with the bottom pulley, which forces the water back to the cistern of the main pumping engine in the pit.
This is effected by carrying through the workings a large volume of air which is kept continually moving in the same direction, descending from the surface by one or more pits known as intake or downcast pits, and leaving the mine by a return or upcast pit.
Such a circulation of air can only be effected by mechanical means when the workings are of any extent, the methods actually adopted being - (i) The rarefaction of the air in the upcast pit by a furnace placed at the bottom; and (2) Exhaustion by machinery at the surface.
The return air from fiery workings is never allowed to approach the furnace, but is carried into the upcast by a special channel, called a dumb drift, some distance above the furnace drift, so as not to come in contact with the products of combustion until they have been cooled below the igniting point of fire-damp. Where the upcast pit is used for drawing coal, it is usual to discharge the smoke and gases through a short lateral drift near the surface into a tall chimney, so as to keep the pit-top as clear as possible for working.
The use of small auxiliary blowing ventilators underground, for carrying air into workings away from the main circuits, which was largely advocated at one time, has lost its popularity, but a useful substitute has been found in the induced draught produced by jets of compressed air or high-pressure water blowing into ejectors.
The increased resistance, due to the large extension of workings from single pairs of shafts, the ventilating currents having often to travel several miles to the upcast, has led to great increase in the size and power of ventilating fans, and engines from 250 to Soo H.P. are not uncommonly used for such purposes.
The lighting of underground workings in collieries is closely connected with the subject of ventilation.
The latter class of coal contains the largest proportion of this dangerous gas, but holds it more tenaciously than do the steam coals, thus rendering the workings comparatively safer.
This may be done by water-carts or hose and jet, but preferably by finely divided water and compressed air distributed from a network of pipes carried through the workings.
Methods for enabling miners to penetrate into workings where the atmosphere is totally irrespirable have come into use for saving life after explosions and for repairing shafts and pit-work under water.
In the thick coal workings in South Staffordshire the slack left behind in the sides of work is especially liable to fire from so-called spontaneous combustion, due to the rapid oxidization that is set up when finely divided coal is brought in contact with air.
In Belgium it was tried in a pit 940 metres deep, where it has been replaced by flat hempen ropes, and is now restricted to shallower workings.
Near Jebel Kouif, on the frontier between Algeria and Tunis, there are phosphate workings, as also in Tunis, at Gafsa.
There are also diamond mines in the Winburg and Kroonstad districts, and near Ficksburg, where old workings have been found 40 ft.
The workings at the Ballycastle collieries are probably the oldest in Ireland.
The town is the seat of a sub-prefect and has a tribunal of first instance; it has trade in phosphates, of which there are workings in the vicinity, and carries on cotton-spinning and the manufacture of leather, paper and sugar.
When the rock is much removed from the surface, or inconveniently situated for open workings, it is quarried in underground chambers reached by levels driven through the intervening mass and across or along the beds.
We have seen that the ultimate cause was the consciousness on the part of the Church that the first age of its own history was characterized by spiritual workings more intense than other times.
It does not, of course, follow that everyone who had shared in the divine afflatus of prophetic enthusiasm gave forth oracles; but the prophets as a class stood nearer than other men to the mysterious workings of Yahweh, and it was in their circle that revelation seemed to have its natural home.
There are large collieries in the neighbourhood of the town, the workings in some cases extending beneath the sea, and blastfurnaces, engineering works, cycle and motor works, shipbuilding yards and paper mills.
In short, the workings of all the Western episcopates, from Africa to the ocean, the Rhine and the Danube, lay outside the ordinary influence of the Roman see.
Gregory claimed that the same condition should apply to bishops, and these were the grounds of the dispute about investitures - a dispute which could find no solution, for it was impossible for the Teutonic sovereigns to renounce all interest in a matter of such importance in the workings of their state.
The Levant mine is the chief, the workings extending beneath the sea.
Traces of ancient workings and several exhausted mines are seen.
The earlier workings were in the Serra de Chapada to the N.W.
The workings at De Beers had extended into the still more deeply seated granite in 1906.
The discussions of the next few years served to make clearer than before the practical workings of the constitution of the United States as a shield and support of slavery; and Garrison, after a long and painful reflection, came to the conclusion that its pro-slavery clauses were immoral, and that it was therefore wrong to take an oath for its support.
How these revelations actually arose in Mahomet's mind is a question which it is almost as idle to discuss as it would be to analyse the workings of the mind of a poet.
The workings in Great Britain represent the annual abstraction of rather more than a mass of rock equal to a foot in thickness spread over a square mile.
The ancient workings, consisting of shafts and galleries for excavating the ore, and pans and other arrangements for extracting the metal, may still be seen.
Modern mining at Kolar dates from 1881, but there are extensive old workings showing that much gold had been extracted under native rule.
There are collieries near the town, the workings extending beneath the sea; there are also iron mines and works, engineering works, shipbuilding yards, breweries, tanneries, stone quarries, brick and earthenware works, and other industrial establishments in and near the town.
The manufacture of matches is aided by the existence of sulphur workings in the vicinity; and Albacete formerly had an extensive trade in cutlery, from which it was named the Sheffield of Spain.
The mining product next in value to coal in 1908 was copper, taken chiefly in Carbon county in a zone of brecciated quartzite underlying schist, the original ore being chalcopyrite, with possibly some pyrite, a secondary enrichment, which has produced important bodies of chalcocite in the upper workings, but these are replaced by chalcopyrite at greater depth.
Having spent his youth in the papal diplomatic service - he was nuncio at Brussels from 1843-46 - he had a certain knowledge of the workings of parliamentary institutions, while the years immediately before his accession had been spent as archbishop of Perugia, so that he was not closely identified with any of the Vatican parties.
Native copper is found in most copper-mines, usually in the upper workings, where the deposit has been exposed to atmospheric influences.
It was not until 1864 that Zoutpansberg was definitely incorporated in the South African Republic. Trichard and his companions had been shown gold workings by the natives, and it was in this district in 1867-70, and in the neighbouring region of Lydenburg, that gold mines were first worked by Europeans south of the Limpopo.
The glen to the east of the town, in which are abandoned workings, is called the Silver Glen.
In 1809 he published at Hamburg his Theoria motus corporum coelestium, a work which gave a powerful impulse to the true methods of astronomical observation; and his astronomical workings, observations, calculations of orbits of planets and comets, &c., are very numerous and valuable.
Herbart apperception is that process by which an aggregate or "mass" of presentations becomes systematized (apperceptionssystem) by the accretion of new elements, either sense-given or product of the inner workings of the mind.
There is also a considerable working of brown iron ore at various points in Lincolnshire, Northamptonshire and Leicestershire; with further workings of less importance in Staffordshire and several other districts.
He will not admit that there is any evidence of true virtue in the approbation of virtue and hatred of vice, in the workings of conscience or in the exercises of the natural affections; he thinks that these may all spring from self-love and the association of ideas, from " instinct " or from a " moral sense of a secondary kind " entirely different from " a sense or relish of the essential beauty of true virtue."
He soon satisfied himself that the artist who was content to reproduce the external aspects of things without searching into the hidden workings of nature behind them, was one but half equipped for his calling.
For the purpose of getting rid of the water, and obviating the flooding of such deep workings, it has been found necessary to construct drainage works of some magnitude.
In the ancient workings, many of which are in the same condition as they were left 1800 years ago, there are in all 2000 shafts and galleries.
Wicklow, where regular workings were established about 1796 but were destroyed during the Rebellion.
An Ivy League professor detailed the workings of the brain while another discussed time, with both concluding it was absolutely impossible.
In stark contrast to its coverage of the mayor, the media has not focused very much on the workings of the general assembly.
I gained invaluable insight into the workings of an international current affairs magazine.
It is possible to enter this adit wading through the water and penetrate the old workings for a considerable distance.
A shallow adit driven from near the old reducing works on the South connects with these workings, its mouth is however choked.
The other is that we will break out back up into the bedding cave that is left behind when entering the lower workings.
Guy says, ' Never invest in an LDAP property whose workings you do not fully comprehend ' .
The water from the stream originally provided the steam to power the workings for grinding the corn for local farmers.
A detailed double page full cutaway shows the internal workings of the tank.
With remarkable skill he lays bare the intricate workings of a highly forensic and complex mind.
Quarries that cut great gashes in the hillside look romantic a hundred years after the workings are abandoned.
It's internal workings are encapsulated -- it does not expose highly granular control of its process.
The workings occur all along the base of the downs, where the narrow strip of upper greensand joins the chalk.
The course analyzes not only the workings of formal markets but also informal, examining the linkages between the two.
This arrangement of dolomitised limestone and overlying mudstone is the most common feature seen through both the prehistoric and more recent workings.
My yearning for discovery now had a focus; my oceans would be libraries, my terra nova the workings of his mind.
The main advantage of the Congress is that it would involve national parliamentarians in the workings of the Union.
On the coast, especially west of Lymington, are significant remains of old salterns (salt workings ).
Bundala National Park This park is a mixture of wetland habitat, open scrubland with some forest and saltpan workings.
Dark Age centered on 600 AD, timber building, evidence of metal workings, substantial metal working, Roman Samian pot shards.
There are trip workings to several private sidings in the Exeter area.
On Still, the only song in English, the lyrical theme is the inner workings of the human body.
Many lakes, waterfalls and old mine workings, as well as a large variety of plants and wildlife are there for the searching.
These former gravel workings now provide excellent habitats for wildlife including many water birds.
After the fall of the Roman Empire the workings remained abandoned until the days of the Pisan supremacy, 3 and were again given up under the Spanish government, especially after the discovery of America.
It merges into physical geography, which takes account of the forms of the lithosphere (geomorphology), and also of the distribution of the hydrosphere and the rearrangements resulting from the workings of solar energy throughout the hydrosphere and atmosphere (oceanography and climatology).
The latter, determined experimentally, varies with different kinds of surfaces of mine workings, whether rough or smooth, timbered or unlined; it ranges from 0.000000001872 to 0.0000000217 lb per sq.
In devising a system of ventilation it is customary to subdivide the workings so that the resistance to the ventilating current in each split shall be nearly equal, or so that the desired amount of air shall be circulated in each without undue use of regulating appliances which add to the friction and increase the cost of removing the air.
It is natural for a man who does not understand the workings of a machine to imagine that a shaving that has fallen into it by chance and is interfering with its action and tossing about in it is its most important part.
I had a ringside view of the strange workings of the paper.
On the coast, especially west of Lymington, are significant remains of old salterns (salt workings).
There is also the chance to have double deck workings but terminating on the eastern fringe of the Beeches.
This batch of streetcars mainly operated from Foleshill depot on the Bedworth route and its short workings.
Although the workings of systems are complex, involving a series of 24 satellites and various calculations using different variables, the end result is really quite straightforward in that it is easy to pinpoint a position.
If you are familiar with the workings of bicycles and experienced with tools, you can build your own bamboo bicycle.
Panic attacks may not appear to have an immediate cause but the inner workings of the mind and emotional responses often function without conscious awareness.
Model Search to learn more about the inner workings of the fashion and art world.
The original Tiki Room was one of Walt Disney's first forays into the now famous workings of audio animatronics, and the Florida version holds plenty of updates and modern humor for every guest who enters through its doors.
Different foes will attack you in different ways, though once you get used to the workings of Fable, it's never that difficult to win a fight.
Since then, the PS3 has gone through several iterations that have adjusted some of its inner workings, including the size of the internal hard drive and its ability to play legacy PlayStation 2 games.
Wet cell phone problems occur whenever the phone gets consistently wet or moisture manages to penetrate the internal workings of the phone.
The Public Vaults features original documents, maps, and films that allow the visitor to feel what it's like to be in the inner workings of the Archives.
This book explains in detail the workings of your child's mind at each stage and how to best approach his education.
This will enable you to really see the inner workings of an outdoor recreation career.
These city museums and exhibits will allow you to see San Francisco below the surface, from cable car workings to botanical garden exploration.
The toys are done in a transparent design that allows kids to see the internal workings of each vehicle.
During a relationship, your partner may find your efforts endearing, but tacking your own elementary workings into your breakup note will not spark her amusement.
This can make dating more of a mind game, but it also helps to understand the inner workings of the opposite sex.
If you don't know how to open-up and share your thoughts and inner workings, you'll soon find yourself looking at a cloud of dust as he runs off to find someone who can.
Arcana means mystery or mysterious, which represents the inner workings of God as the universal truth.
Many theorists believe that astronomers created the zodiac animals to help people who were unable to read and write understand the workings of the universe.
The show focuses on the inner workings and dynamics of larger, working class families with a strong matriarchal character at the helm of each family.
Visitors can tour the inner workings of the dam, see a film about how the dam was constructed, and enjoy the beautiful Nevada scenery that surrounds the dam.
From fine handcrafted timepieces to beautiful (and functional) watches from Switzerland, their intricate workings are highly sought after by everyone.
Regardless of whether a watch is on a diamond pave band or a canvas band, the inner workings should not be compromised.
The movement is the name for the inner workings of the watch, the part that actually keeps time.
When the watch is wound, it winds up a spring, which provides the energy needed to operate the inner workings that keep time.
These high quality materials are used both on the inside workings of the watch, throughout the watch making process, and on the outside features visible to the human eye.
Sellers of these knock offs will tell you that the clear case is so that you can view the inner workings of the watch but only two very rare, vintage watches are available with clear backs and they are under lock and key collections.
Because of the popularity of these times pieces, he soon set up shop in Bienne, Switzerland manufacturing watches and their inner workings.
This might include a case made from gold or silver, high quality watch workings and will often include an area for engraving.
The unisex watch has a smooth metal case and features a small porthole at the back where people can watch the workings of the time piece as they track the seconds and minutes pass.
A skeleton wristwatch shows all the internal workings of a watch.
Unlike normal watches that have a solid face and back, a skeleton watch has a glass section that allows people to see the inner workings of the watch.
The inside or 'skeleton' of the watch can be completely on view or just part of the watch workings can be exposed.
This gives two interesting ways to see the inner workings of the watch.
The skeleton watch has a clear face which shows the unique workings of the watch.
However, before you take your own watch apart and attempt to resurrect its inner workings, make sure the problem isn't too complicated for an untrained person to undertake.
If you appreciate a sneak peek into the inner workings of a clock or timepiece, the Open Heart may appeal to you.
The hand applied graphics on its sunray dial give a subtle boost to the watch's appeal while a flame fusion crystal protects its inner workings.
Like all yoga, a person's breath is critical to the proper workings of the exercise.
A non-profit is run by a board which votes and approves the workings of the business.
Aside from that there are none of the perks you get when workings for someone else.
All it takes is some practice, a basic idea of the workings of a manual transmission, an empty parking lot or dirt road, and a supportive friend to offer advice.
The Hayne's Automotive Repair Manual is a good source of information about the inner workings of the Toyota Prius.
It's important to properly maintain the inner workings of your grill so that it functions properly and to take care of the outside of the unit so the stainless stays shiny and attractive for as long as possible.
The inner workings of the agency are all geared toward the ultimate satisfaction of the customer, from face-to-face meetings with your agent to customizable insurance plans.
The show is based on the workings of the Los Angeles franchise.
Like Miami Ink, each episode of LA Ink takes a look at the inside workings of a tattoo parlor.
The show offers viewers a look at the inner workings of a bridal store and features personal stories of the brides to be who come in looking for their dream wedding gown.
One of the most fascinating aspects for viewers is watching the inner workings of the Playboy Mansion.
Building upon a solid foundation, Rowling establishes a ground floor for the workings of her story with the addition of four characters.
I liked this book because of the great amount of action and fighting, the detailed workings of magic, and of course the dragons.
While Galactica may look like a mechanical sea monster to some, her re-imaged design and inner workings make for a believable setting where the theory behind the show makes this a popular Sci-fi series.
Star Trek ship schematics allow fans to explore the inner workings of these ships and understand their layout and more.
Skin rashes, bad luck and even nightmares were ascribed to the workings of elves.
The layers may not stick together, so that even a minor injury leads to large blisters as the layers separate, or there may be other problems with the workings of the skin.
I was less critical than my wife on the slow workings of the law.
It was Blackie Rowland's old workings, back during the war, Roger answered.
The Roman workings too, to judge from similar finds, seem to have been considerable.
The theist believes that he can further trace many incomplete workings of the monothesitic instinct in the history of religion.
While the width of the working-place is thus limited by the strength of the roof, its length is determined by other considerations - namely, the rapidity with which the mining work can be conducted and the length of time it is practicable to keep the working-place open, and also by the increased difficulty of handling the minerals sometimes experienced when the workings reach undue length.
For deep workings the milling method is usually employed, in which the ore is excavated in funnel-shaped pits, each of which connects with underground haulage roads by a shaft.