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By H. C. Miller

THE gas-lift method of flowing oil from wells is the outstanding feature of petroleum technology today. Its forerunner, the air lift, was used successfully first, in the Baku fields of Russia, in 1899, and later in the Gulf Coast fields of Texas and Louisiana and the Kern River field of California. It is still used to a limited extent in certain oil fields. The use of compressed natural gas for lifting oil from wells has supplanted the air-lift method in a measure in those fields where a sufficient quantity of gas accompanies the oil to make the gas lift possible, or where natural gas is plentiful and inexpensive. We find therefore in California, that, natural gas is used at practically every well where a gaseous medium is employed to flow the oil. The use of natural gas has many advantages over that of air. It is possible to recover and save the gasoline from the gas that accompanied the oil to the surface. This gasoline would be wasted if air were used as the lifting medium. Also, certain proportions of air and gas form an explosive mixture that cannot be handled safely by compressors. Another advantage that gas has over air is that gas under pressure is more soluble in oil. Gas in solution in oil reduces the viscosity of the oil that is being produced and causes it to flow more readily through the. tubing and flow lines. The gas lift has made it possible to recover many thousands of barrels of oil from deep wells in California that could not have been produced otherwise. It would not have been economical, had it been mechanically possible to produce such wells as the world's deepest producing oil well (Miley Athen's No. 6, Rosecranz field, California) by any other method of pumping known today. At this well, production is obtained from between 7305 and 7591 ft. and 11 months after completion of the well, production was being maintained on the gas lift it approximately 2000 bbl. a month. The crookedness of the hole, or its diameter and depth will not prevent the successful application of gas-lift pumping when other conditions are favorable.

Jan 1, 1927

By Hugo Julien

According to OSHA 29 CFR Part 1910.119 (Process safety management of highly hazardous chemicals), Canadian Provincial Safety Standard Acts or Federal laws, the owner of stationary equipment (Boilers, stacks, piping, pressure vessel, etc.) should follow a complete inspection plan and follow an Integrity Operating Windows (IOW’s) adapted for each of them. Some important variables shall be included in the inspection plan such as specific damage mechanisms versus alloy used in the original design, process conditions, etc. Some North American’s standards exist, like the one listed in ASME PTB-2-2009, to help owner to create such inspection program. The new API RP 584, Integrity Operating Windows (IOW’s) can guide Mining & Metals owners to find out their specific IOW’s. Inspection frequencies are often described in the Jurisdiction Safety Acts such as the British Columbia B.C. Reg. 104/2004, etc. but often left in the owner representative responsibility (Bill C-21, federal Act to amend the Canadian Human Rights Act). Every deficiency should be repaired according to recognized Codes such as ASME PCC-2, etc.. If flaws not conforming to the original Code of construction are found, this article will introduce the Fitness-For- Service assessment principles to be able to accept it without any repairs.

Jan 1, 2014

By Edward Bottomley

Mr. Chairman and Gentlemen: I tried to get Benedict Shubart to have some fellow-some big fellow with a big voice-to read this paper for me, but he said there was nothing doing; [ ] that I would have to read it myself. I will try and not take up too much of your time. It is a pretty big subject, Mechanical Loading, and it covers a good deal of ground. I have merely touched on the high spots, as it were. A great deal has been preached and written in the last year or so about mechanical loading, and I doubt if any other subject in the mining industry has been discussed so freely and as often in the last few years. It is not the intent of this paper to dwell on the merits or demerits of any [ ] particular type of loader, that is, to say what the writer thinks is the most efficient or most inefficient machine. There are several types of loaders on the market to-day that are proving very successful in many mining districts. Some of these, five or six years ago, seemed to be a miserable failure from every standpoint, mechanically

Jan 1, 1926

PRESIDENT BOTTOMLEY: Gentlemen, the next order of business, if you wish to discuss it is Mechanical Loading. We still have a little time left that could be devoted to that subject, and the meeting will be open now for that purpose. Where is Mr. Edge- worth? J. E. EDGEWORTH (Foreman, Union Pacific Coal Company, Rock Springs, Wyoming): Here. PRESIDENT BOTTOMLEY: Yon start the ball rolling. Tell us what you are doing in the Rock Springs District, on the mechanical loading. SECRETARY SHURART Mr. Edgeworth is the man at the face handling the coal. He never sees the light of day these late winter mornings.

Jan 1, 1927

By H. F. McCullough

MECHANICAL loading and conveying equipment has been available for the coal-mining industry for more than twenty years. The earlier equip-ment-was admittedly crude and ill-fitted to perform its intended functions, but there are available today a variety of mechanical loaders and conveyors which may be said to be almost on a par with coal-cutting machines. Despite the fact that such equipment is available and that better and other types of equipment are continually being developed, mechanical loading of coal cannot yet be said to be economically successful, except in a few special cases. It is not an accomplished fact in the sense that machine cutting of coal and electric haulage are accomplished facts and a part of accepted practice. There are two general opinions why we have failed to obtain better results with mechanical loading and con-veying equipment. The equipment manufacturers will say that coal-mine operators have generally failed to establish and maintain the conditions required for suc-cess. The coal-mine operator says that the equipment is not adapted to cope with his specific conditions to the extent required for economically successful results. Just what is the objective of this movement toward mechanical loading? We speak of mechanical loading in such a way as to lead one to believe that we are mere-ly seeking a mechanical equivalent of the human loader and his shovel. Really, we are impressed with the fact that the coal-mining industry has not advanced toward greater productive efficiency to anything like the degree achieved by practically all of the other productive in-dustries, and we are seeking the means to remedy this. We have seen the advantages which follow the intro-duction of coal-cutters and electric haulage-locomotives. The loading of coal is the one major operation in coal mining which has not been mechanized. We believe that a satisfactory, mechanical substitute for the man with the shovel will help us increase our productive efficiency to the same degree as has been accomplished in the other productive industries.

Jan 3, 1927

TWO hundred enthusiastic engineers and coal, op-erators attended a joint meeting of the A. I. M. E., the National Coal Association, and the American So-ciety of Mechanical Engineers in the auditorium of the Alabama Power Co. building at Birmingham, Ala., on Jan. 21. S. W. Farnham, mining engineer of the Goodman Manufacturing Co., Chicago, in his paper on mechanical loading of coal discussed the feasibility of scraper and machine loading. A. R. Anderson of the Jeffrey Manufacturing Co., in a paper on loading coal with conveyors covered their adaptation for long-wall mining and for loading into cars. Discussion of these papers was hampered because the cheap labor costs prevailing in the district have handicapped gen-eral mechanization of the mines. The Bureau of Mines film, "The Story of a Rock-dusted Mine," showing the New Orient mine, West Frankfort, Ill., was also shown at the meeting. F. H. Crockard, president of the Wood-ward Iron Co., represented the A. I. M. E., S. L. Yerkes, vice-president of the Grider Coal Sales Agency, and J. L. Davidson, secretary of the Alabama Mining Institute, represented the National Coal Association, and Paul Wright represented the American Society of Mechan-ical Engineers.

Jan 2, 1927

By Wm. H. Woodhead

Improved methods of mining have accompanied the introduction of mechanical loading, of which there are a great many varieties, but this multiplicity of mining brings new problems and greatly increases the importance of managing over a few years ago. Few mines operating today have been opened with the intention of mechanizing throughout. The problem of mechanization is to change over a mine heretofore operated by hand methods and to select machinery that will fit the old system with the least number of changes, the aim being not to disrupt or to completely change the original plan. The organization of mechanical and electrical forces is a problem in mechanical loading, and each individual mine presents its own problems. Plans which may succeed in one mine may fail in another and upon the management rests the responsibility of deciding the best method in each case.

Jan 1, 1930

By S. W. Farnum

ABOUT three years ago at a coal mining institute meeting, it was predicted that mechanical load-ing underground would progress faster than either the electric coal-cutting machines or electric loco-motives had in previous years. This prediction has proved correct so far. In 1925 over 6,000,000 tons of,coal was loaded mechanically underground in the United States and it is estimated that the 1926 tonnage will reach 10,000,000. The use of electric mining machines and locomotives .has prepared the way for quick results. Most coal mines are now equipped with electric power and have a competent staff who understands its use. In spite of this advantage the introduction of the loading machines brings many new problems. Im-proved and concentrated transportation; doing the drilling, shooting, tracklaying and face timbering with company men instead of the former tonnage men; doing the work on the new basis in an economical and efficient manner; altering or modifying mining systems where necessary to further improve the work and reduce oper-ating costs; improving the percentage of lump coal and reducing the slack content where desirable; improving the cleaning of the coal and obtaining a more dependable .and uniform output are a few of the problems that must be met. Each of the different types of loaders now on the market has its particular advantages and disadvantages for a given mining condition. Even with the same mining conditions one type will work well under one ;system of handling, whereas another may favor another system or mining method.

Jan 5, 1927

By S. W. Farnham

We have listened to many papers describing mechanical loaders, and systems of mining planned to increase their efficiency. We have become familiar with the various types and in a general way, their capacities and limitations. Messrs. F. E. Cash and E. H. Johnson in Bulletin 17 of the Carnegie Institute of Technology, subject Coal Mining Investigations, have a very complete review of the loading situation then. Mr. A. W. Dickinson, in a recent paper before this Institute, gave a later illustrated review of mechanical loaders. On page 28 of Cash & Johnson's paper is a list of loading machines to which might be added to bring the list down to date, the following: Under Digging and Loading Machines The Goodman Power Shovel Under Scraper Loaders The Goodman 436-G-3 125 H. P. three drum Scraper loader The Goodman 35 H. P. Entry loader and the Two Drum 125 H. P. Hoist built by Vulcan of Denver for scrapers Under Shaking Trough Conveyors The Eickhoff Conveyor The Link-Belt Conveyor The McCarty Duck-bill which is really a digging and loading element built to attach to the end of and operated by a reciprocating conveyor. The outstanding feature in this line of work in the past few years is the fact that a few very successful operations have been worked out on a large scale; the officers and staff in charge of this work have gone into details very thoroughly and altered and improved, in many cases, their mine equipment and mining methods, and by the exercise of persistent energy and intelligent effort, in the face of frequent difficulties and discouragements, they have attained results that are far ahead of the average loader operation. The coal mining industry owes much to these men for the pioneering and development of mechanical loading; their investigations in transport, shooting, shearing, snubbing, cleaning, and production costs, the results of which they have given freely and frequently to the public, are of great value. Foremost among the pioneers in this work are the Union Pacific Coal properties, the Quealy properties, the Sheridan Wyoming Coal Company and in the Central West, the Union Colliery Company of Illinois. On the other hand, in the great majority of installations, one loader, or possibly two or three loaders have been started in a given operation and through failure to make the proper effort to improve their transportation and work out the systems to utilize their loading machines, the loaders have not shown appreciable savings and in many cases, the installation has failed. It has been frequently stated in many meetings where loading has been discussed, that the idea of mechanical loading must first be sold not only to the operating staff but to the entire personnel of any company where installations are made. The problems involved in the successful application of this equipment are such that it requires enthusiastic and wholehearted teamwork on the part of everyone connected with the work and when difficulties arise, they must be ready to exercise initiative and try new ways oftentimes of overcoming impediments. The closest attention now is given to the question of economics how much will a loader reduce the cost of coal in any particular situation? Without fear of successful contradiction, I believe that experience up to date has unquestionably shown that where the shovel type of loader can be properly used, it produces in wide work, the cheapest coal of any loading device yet brought onto the market. Naturally there is a considerable difference between the results from different makes of shovels.

Jan 1, 1926

By S. W. Farnham

Those who remember the years of patient effort and the slow results obtained in the first introduction of electrical coal cutters and locomotives will, I think, admit that mechanical loading of coal is unquestionably being established at a much more rapid rate than any previous application of machinery to reduce manual labor in mines. There are many operators who consider the progress of the loaders today as slow, but considering the number of years it took to thoroughly establish electrical coal cutters and locomotives, and comparing it with the short time that the mechanical loader has been on the market, and the results that have been obtained today, they will admit, I think, that the progress of the latter is much more rapid. It is about 35 years since the advent of the electrical coal cutter and electric locomotive. Their use has brought about these improved conditions, increased tonnage per mine and other features, which are of assistance to the installation of mechanical loaders. The management and the technical staff in practically all of the American mines are trained in the use of electrical machinery and understand its operation, care and maintenance. . There is frequently, a surplus of electrical power and wiring available to take care of the small requirements of the electrical loader. The mechanical loader, therefore, starts today with the ground prepared for it. Those manufacturing companies who have had years of experience in the design and construction of mining machinery, know in a large measure what to incorporate in their designs to make the parts of the new type of machine effectively strong and to operate with efficiency under the severe conditions encountered in mining service. All these advantages greatly assist the success of a new type of machine such as the mechanical loader. In spite of these advantages, however, there are bound to be some failures. All new types of loaders have to be developed. We hear of some that are a success and some that are set aside. The field of application of each type and its limitations first must be determined by actual operation. The earlier loaders had to be changed and improved in design as weaknesses developed. Not all of the new types of coal loaders have been built by mining machinery manufacturers of long experience, and the lack of experience in this line is responsible for some of the early failures. The coal mining company staffs and also those of the loader companies had to learn what the operating factors were that made mechanical loading a success. The difference in results obtained by loaders in different properties under similar physical conditions indicates that the mine management is a very large, if not the major factor, affecting the efficiency of mechanical loading. Many articles have been written on the question of loading. The subject has been quite fully discussed at recent coal meetings and in the technical press. It is not always as easy or simple a matter to form conclusions as may first appear as to one's own particular loading problem. Mechanical loading is a comparatively new art, and many companies while claiming that loaders are quite successful, do not have an accurate line on the actual saving they are affecting. Many of them have only a few of the factors taken into account in their costs. Many loaders have been generally bought without very careful consideration given to all details and except where extremely favorable conditions prevail, failure resulted. When contemplating the installation of mechanical loading, one naturally desires to select the type of loader that will, fit his mining conditions. The things

Jan 1, 1924

By T. H. Butler

The two most talked of questions in the mining industry today are rock dusting and mechanical loading. The one as a matter of safety, and the other as a matter of economy, and both are of vital interest to the mining fraternity. Rock dusting and other safety methods will be dealt with by others at this meeting, so I will confine my few remarks to the matter of mechanical loading. I will not attempt to tell you what mechanical loaders are doing in the different mining fields throughout the country, or what they should do, but will endeavor to give you an outline of the work being done with mechanical loaders in No. 4 Mine of the Union Pacific Coal Company, at Hanna, Wye. In order that you may better understand and be in a position to follow me it will be necessary to cite the conditions under which we are working. and the type of loaders in use. The seam pitches from 14 to 17 degrees, and is normally 32 feet in thickness, and is overlaid with a soft sandstone roof. The panel system of working is used, planes being driven on the pitch, and rooms driven on the strike. Owing to faults being encountered planes are driven between the faults, and the. rooms on either side are in some instances 800 to 1,000 feet in depth. Rooms are advanced eight feet in height, and 32 feet in width, by hand loaders and .Toy mechanical loaders, and when driven to the boundary,, 18 feet of the remaining 24 is loaded out with Thew electric shovels, and six feet left to protect the roof. In January, 1916 the company installed a Type 1 Thew shovel, equipped with a 1 1/4-yard dipper, and in July, 1917, they installed a Type 0 Thew electric shovel, equipped with a 1-yard dipper, and in the year 1918 two additional Type 0 Thew shovels, equipped with a 1-yard dipper, were installed, making a total of four Thew shovels for this mine. The introduction of these shovels caused the employees much concern, and like all departures from the old methods of mining, met with indifference by some and open antagonism by others, so that for some time they results obtained were not satisfactory. However, by constant supervision and changes in the method of haulage the results obtained at present, while not entirely satisfactory, are much better and the production and costs are reasonably good. The Thew shovels in use are mounted on traction wheels with swivel axle and move. in all directions by their own power, and while the weight of each is approxi¬mately 20 tons, they are not as cumbersome as. one would think and are easily operated. The system used in working these shovels is to shoot the coal clown ahead of the shovels and maintain two tracks, two cars being used on each track so that shovel is loading on one track while driver is, changing cars on the other. When place is finished the shovel is run back to the first cross-cut by its own power and lowered to the next room with block and tackle, the roof coal in cross-cut being shot down to a height of 16 feet to allow passage of the boom. With better results from the Thew shovels we soon realized that it was necessary to find some method of developing rooms faster than was being done with hand loaders in order to keep the Thew shovels in working places, and in November, 1923, the company purchased from the Joy Machine Company two Type 4 B U Joy loaders, and the installation of same met with the same indifference and antagonism from the employees as did the Thew

Jan 1, 1924

By Charles Gottschalk

Some time after my arrival in Rock Springs to fill a short engagement with The Union Pacific Coal Company, Mr. Dickinson informed me that he had placed me on the program for a paper entitled "Mechanical Loading in Indiana." Since development of mechanical loading operations on a genuine coal producing basis for that section began near Oakland City, Indiana, and rapidly spread over Southern Indiana, Western Kentucky and Southern Illinois simultaneously, the results referred to are in many ways common to all three states. Prior to December, 1922, several attempts at mechanical loading had been registered, notably among which were installations of the Jeffry Entry Driver, and the Meyers-Whaley loader. The object of most of these earlier installations was quick development rather than lower production costs in face loading. In this measure it is claimed the machines were at least partially satisfactory. Three items which seemed to delay rapid progress in the adoption of either machine were, excessive first cost, height of coal seam necessary, and timidity of the operator relative to the labor situation which might develop. When the Joy machine was put on the market in the form of the 4-B.U., with a clearance overall which would perform in coal slightly under five feet in height, and at a cost price of less than one-half that of other machines being sold, many operators were at once ready to take a chance along with the manufacturer. This desire was accentuated by the difficulty to operate coal mines at all at prevailing production costs. This condition also made the coal miner more receptive to machinery which would give added employment to the field. At the convention held in Cincinnati during May, Mr. .Joy stated that about 200 of his machines were in operation at that time. Mr. Whaley said that about 40 of his were in use in coal mines. It is probable that of the above sum 75 machines were installed in Indiana, Illinois and Kentucky. Since that time, possibly 50 more machines of later design have been added. Like many of our troubles, those which seemed most difficult to overcome, proved in the end to have been least of all, and in this case the sup¬posed resistance which labor would advance has been more or less imaginary. In Illinois and Indiana a scale of wages is being accepted which is consistent with average earnings of machine men. The fact that a large number of coal operators want and are buying more loading machines has encouraged mining machinery manufcturers on every hand to devote renewed vigor to the cause and it is generally understood that new types and models are being developed both in factories and mines with the coal industry eager always to see the latest development. I understand that at present the Goodman, the Jeffry, and the Sullivan machinery companies are each offering new designs to meet Indiana and Illinois requirements. It is not strange that with so many installations many were made as a result of an impulse to ride the band wagon without any serious attempt to study the results or draw any conclusions from the experiences of others with loading machinery.

Jan 1, 1924

By A. W. Dickinson

Since the day when one of the most progressive of our flat-head for- bears used a pry pole to loosen large rocks to crash upon the head of his, enemy, thereafter making notes of his performance on tablets of stone, the arts of mechanicalization have developed and progressed to the benefit of mankind. In the early coal pits of England the crudest of tools were wielded in the most slavish of toil to win a very small amount of product. In our own country it is but a few years since coal was hewn by negro slaves in the mines of the southland. The past thirty years have brought the use of the mining machine, power drill and locomotive, and we now stand on the brink of the coal mining era that will change the toiler of the mines into a skilled mechanic and render far more safe the winning of the fuel necessary to the nation's need. The ingenuity of our citizens has made it imperative that coal be produced at a lesser cost. Vast supplies of fuel oil have been developed; enormous resources in water power are turning the wheels of many mills and, most commendable but distressing to the coa.1 producers, the high price of coal has resulted in efforts and accomplishment in fuel economies unheard of a short five years ago. The railroads of the United States alone in 1924 accomplished more hauling with $30,000,000 less in coal bills than in 1923. The loading of coal by machines has been under investigation and trial for some time past and in an effort to have its men informed of the practice of the eastern coal fields, The Union Pacific Coal Company sent the writer through a number of states to view as many operations as possible. Notes were taken of machines and processes seen and time was spent with engineers of the various coal companies; also with the United States Bureau of Mines Engineers, particularly Mr. Edwin H. Johnson, who devoted one year to the most careful study of the mechanical loading of coal. The writer wishes, at this time, to acknowledge the helpfulness of the information acquired through contact with Mr. Johnson.

Jan 1, 1925

By John Kostuik

AT the Sladen-Malartic mine, a number of orebodies have been mined, some by shrinkage and others by open sub-level scopes, from which the ore is handled either through a grizzly system or by mechanical loaders. This paper deals with the comparative costs and relative merits of the two handling arrangements. The facts brought out in this comparison have a bearing on the selection of a proper handling method. The mine is in Fourniere township, northwestern Quebec, about forty miles east of the town of Rouyn. It is served by the Rouyn-Senneterre branch of the Canadian National railways. Two vertical three-compartment shafts give access to the present workings. No. 1 shaft, at which the plant is centralized, is the main hoisting shaft, with five levels to 950 feet. No. 2 shaft, 2,400 feet east of No. 1, is under development, with four levels to 725 feet. At the main shaft, the ore is hand-trammed in 1 1/2 tons cars from the scopes to the stations o:i each level and hoisted in cages to surface at a rope speed of 900 feet per minute. Air-operated tipples are used to dump the ore through grizzlies of 14-inch openings into a surface bin of 150 tons capacity. The ore hoisted at No. 2 shaft is trucked from the headframe bin to the mill. Milling commenced in January, 1938, ar a daily rate of 250 tons. Within two months this rate was increased to the unit's maximum capacity of 325 tons. A second unit to treat a further 325 tons daily was installed in April, 1939. The orebodies mined at No. 1 shaft are parts of a silicified zone at the contact between syenite porphyry and greywacke. The zone is ten co sixty feet wide, strikes easterly, and dips to the south at 55 to 85 degrees. The hanging-wall of the zone is marked, though not precisely, by a strong gouge fault. Locally, the boundary of silicification may be as much as twenty feet either above or below the fault, but for practical mining purposes the fault is the hanging-wall of the ore-zone. The footwall roughly parallels the fault, but as an assay wall it is usually irregular in detail. The ore is dense and hard, a siliceous replacement of both porphyry and greywacke, mineralized with fine disseminated pyrite.

Jan 1, 1941

By A. K. Croteau

"At Craigmont Mines Limited, Merritt, B.C., the mining practice of trackless sub-level caving was started in the latter part of 1966. This type of mining was new to the mine personnel and the mining industry of Canada as a whole. Sub-level caving has presented many old and a number of new problems in maintaining the equipment used in this method. This paper will deal with some of these problems as they affect this particular mining operation. It will be impossible to review all phases of the equipment, but an attempt will be made to cover the most pertinent aspects in maintaining the drilling, mucking and hauling, and auxiliary equipment."

Jan 1, 1970

ATTENTION has recently been directed to the subject of dust production and methods of allaying same in the Broken Hill mines, so that the time would seem opportune for the local branch of the Institute to discuss certain features of an important phase of the health question in connection with underground work. Tests conducted in the Broken Hill South mine and at other mines at Broken Hill have shown that the ordinary operatioils of mining, such as boring, blasting, and shovelling, may be accompanied by the production of considerable dust unless water is judiciously used.In South Africa·dust particles under 5 microns size are regarded as dangerous, becailse they are so small as to be invisible to the naked eye, and wm esc'ape the protections set up by nature in the nose and throat, and thus may be inhaled in large quantity. A micron is 1 25000th part of an inch. This paper contains an account of the work done on the Broken Hill South mine chiefly, though some tests were done on other local mines.An acknowledgment is due to Mr. T. A. Reid, of the Broken Hill South mine, who conducted some of the tests herein mentioned, and under whose supervision most dust counts were made. Numerous dust samples have been taken by means of thekonimeter, an instrument designed by Dr. Kotze, the Government mining engineer of the Union of South Africa, and fully described...

Jan 1, 1921

By Cherie M. Tilley

The Stillwater Mining Co. of Nye, MT, is operating a platinum-palladium mine that requires an extensive system of footwall laterals to facilitate mine production. The 10-year mine plan calls for more than 48,300 lineal m (160,000 lineal ft) of footwall lateral. A rapid tunneling and raising system is necessary to sustain mine production schedules and achieve production goals. This article describes the results of using a Robbins 4.1-m-diam (l3.5ft-diam) tunnel boring machine (TBM) to develop the footwall laterals and a Robbins RBM-6SP raise boring machine to develop raises at the mine. The Stillwater Mining Co is a partnership between Chevron Resources Co. and Manville Corp. Chevron Resources is the managing partner. When the mine began production in September 1986, the owners were primarily concerned with the actual production of platinum and palladium, the grade minable and the amount that could be mined. As mine development and mine production proved feasible, the owners considered higher production levels. The Stillwater Mine is developed by a system of adits (known as footwall laterals) that are driven parallel to the ore bearing zone. This led mine officials to consider using a mechanical boring machine in the primary mine development. Previously, tunnel boring machines have not been used successfully in mining applications. Therefore, the owners decided to purchase a used machine to reduce the potential risk.

Jan 1, 1991

By Richard E. Gertsch

A century of experience with mechanical excavation machines is beginning to pay dividends to the mining industry. Mining is moving from mechanical excavators to mechanical miners. These mechanical mining systems are poised to make a significant impact on hard-rock mining, both underground and surface. Mechanical mining machines have had a long and successful career in coal and evaporites ("soft-rock") mining. Unlike most mechanical hard-rock mining, these systems actually mine ore. For example, the most productive underground method has been, arguably, longwall mining. Mechanical excavation machines are mostly used in civil tunneling or in driving mine openings such as vent shafts. Civil tunneling is a notable mechanical excavation success. Even with its high capital cost, a tunnel boring machine (TBM) can drive kilometers (miles) of tunnel at very low cost. In hard-rock mining, mechanical excavators bore tunnels, raises and shaft openings in the mine, but rarely mine ore. Like the soft-rock miners, their contribution to mining is important and their development must continue. Generally, they are used as excavators not miners. Current trends guarantee development of true general-purpose hard rock mechanical mining machines. Mechanical miners will become a complete mining system and will determine the design of the mine. Mechanical methods will reward the operator with lower costs and high productivity.

Jan 1, 1992

By G. Stuart Jenkins

CONDITIONS at the properties of the Consolidated Coal Co. had reached a point where improvements were almost impractical. The mines, sunk years ago, had shafts and entries so small as to preclude the use of large mine cars. A radical change was necessary in the type of mining and also in the type of mine to accommodate such haulage units. After due consideration, the company decided to enter the field of trackless mining, utilizing belt conveyors and chain-flight conveyors, the belt conveyors to take the long haul, and the chain-flight conveyors to be used for gathering. It was decided not to sink a shaft, but to drive a slope on an inclination of 17 1/2°, which the company believes to be about the limit on which coal can be carried on a belt without rolling back unduly.

Jan 1, 1939

By R. J. Robbins

The mechanization of hard rock underground mines offers a large potential for reducing cost, improving efficiency, and increasing profitability. However, in spite of serious efforts by quite a number of equipment developers and mining company initiatives, the industry has achieved little real progress. The task is difficult and the blasting alternative to mechanical excavation is an effective and well-developed method, which continues to improve in spite of its inherent limitations. A large number of machines have been built and tried. Only a few developments have succeeded to make a major impact on underground hard rock mining. It is certain that hard rock mines would be laid out and designed quite differently if the mining engineers knew they had available continuous mechanical excavation machines. In the absence of the machines, mines will be designed for excavation by traditional methods. It is not easy to utilize mechanical excavation in a mine which is designed to operate with normal drill and blast excavation. This is certainly an impediment to machine development. But what if an ore body cannot be mined conventionally, simply because the mining company cannot get permits to satisfy the ever increasing strict EIS requirements of the general public and governmental agencies? This may provide the incentive necessary to develop the equipment that will be needed by a new mining method that will have almost no impact on the environment.

Jan 1, 2001