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By Thomas Barkley

Mining tradition holds that a parallel round underground can not be any deeper than it’s smallest face dimension. ln other words, a mine using a 12’ (3.7 m) high by 24’ (7.3 m) wide room and pillar mine, the deepest pull that can be achieved is plus or minus 12’ (3.7 m). After experience with decking of rounds in a 12’ (3.7 m) diameter shaft to achieve more than 12’ (3.7 m) advance per round, the concept of deepening the pull on horizontal parallel rounds seemed to be a feasible concept. Tests were conducted in a conventional room and pillar metal mine with a round size of 12’ (3.7 m) high by 24’(7.3 m) wide. Standard rounds were drilled with a 16’ (4.9 m) steel as parallel rounds to an average depth of 14.5’ (4.4 m). The average depth of pull on these rounds was about 13’ (4.0 m). Using the available drilling equipment, 20’ (6.1 m) drill steel was used to drill holes to an average depth of 18’ (5.5 m). Five rounds were drilled and shot with a resulting aven$e pull of 16.2’ (4.9 m) or 90 % of drilled depth. Rounds were designed with decked bum cuts to maximize depth of pull in the cut area An innovative method of de&mining drilling accuraq was used to estimate it’s effect on depth of pull in the rounds. This method used a standard automatic 35-mm camera and scaling to determine the average drill deviation for many of the holes in the rounds.

Jan 1, 2000

By Ernest P. Hall

At the SME Fall Meeting held in Phoenix, Ariz. last October, Ernest P. Hall, addressing an Air and Water Pollution session, noted that water pollution caused by acid drainage from bituminous coal measures had begun long before recorded history. "Until recently," he said, "man did not begin to understand the physical phenomena which took place to cause [it] and even today he does not know what can be done to prevent it." CAUSES "It is known from the reports of early explorers that drainage from bituminous coal measures was causing water pollution before coal mines were opened on this continent. They noted the nature of the polluted water in the runs and creeks and predicted the presence of substantial deposits of coal based on the appearance and character of the water. Even today, polluted water drains from virgin coal areas which have not been touched by mining machines," Mr. Hall said.

Jan 1, 1966

By Charles B. Manula

This paper describes the development of a mathematical model for simulating the behavior of a longwall coal production system. The longwall simulator is a design simulator incorporating both deterministic and stochastic methods to calculate: (a) the size and density of support; (b) the cutting force, power requirements and haulage speed for the loader-shearer; (c) the conveyor size, speed and power requirements; and (d) delay generation at head and tail-gates and the longwall face.

Jan 1, 1978

By Walter R. Hibbard

Whether we have occasion to think of it or not, an adequate and economic supply of energy fuels is vital to each of us. It is interesting to look ahead at the way in which fuels from supplementary sources will begin to enter into the energy mix to help meet the long-term national energy needs. From 1947 to 1965, the average annual rate of growth of energy consumption was 2.7%, with total energy demand in 1965 being equivalent to 54 quadrillion Btu's. During this short period of 18 years, the cumulative output of coal in the U.S. was 9.6 billion tons; natural gas, 193.5 trillion cu ft; and crude oil, 45.9 billion bbl. During the next decade and a half the nation's energy requirements are expected to grow at an average rate of 3.3% yearly, with consumption of energy expected to reach an annual rate of about 88 quadrillion Btu's by 1980, or 63% over the 1965 level.

Jan 12, 1967

By James A. Todd

Use of AN-FO in underground operations has greatly reduced the cost of primary explosives. AN-FO is also less sensitive than conventional dynamites, and when properly used, is safer. Maximum safety in the use of AN-FO, however, requires an understanding of potential hazards from toxic fumes as well as static electricity developed in pneumatic loading. Safe limits and guides have been established to permit most operations to pneumatically load holes that are bottom primed with electric blasting caps, but the toxic fume hazard is less widely understood. During 1959-1960 Du Pont cooperated with the U.S. Bureau of Mines to study the toxic fumes produced by prilled ammonium nitrate-NO. 2 fuel oil mixtures. The conclusions from this work were that oxygen balanced AN-FO, when thoroughly mixed, well primed and well confined in dry holes, produces no greater amounts of toxic fumes than conventional dynamites rated Class I by the Institute of Makers of Explosives. The study also showed, however, that any deviation from these guides tends to increase significantly the quantity of toxic fumes produced. This work was reported by the Bureau of International Symposium on Mining Research at Rolla, Mo., in February 1961.'

Jan 4, 1963

By M. J. Coolbaugh

There is a need for concepts and techniques developed specifically for blasting in areas where the rock is loose or highly fractured. Common practice has been to use techniques developed in hard homogeneous rock and reduce the amount and strength of explosive. However, this rule cannot cope with all of the special characteristics of highly fractured rock and has not adequately taken care of the problems of overbreak, gouging, and wall damage. The main problems encountered when blasting in highly fractured rock are controlling the amount of rock broken, minimizing the damage done to the remaining wall material, and adapting blasting methods to rapidly fluctuating ground conditions. In addition, because it frequently needs timber support right into the blasting area, there is also the problem of how not to shoot out the timber when heavy loading is needed in order to offset a loss of impact caused by deflection of the detonation wave off the numerous rock interfaces, and by the absorption of the wave by resilient clay particles. Another consideration is the fact that less attention needs to be directed toward producing satisfactory fragmentation of the broken rock. Those blasting methods designed for breaking hard rock into manageable segments are, as a rule, not needed in highly fractured rock which will usually break along its own numerous fracture lines.

Jan 8, 1965

By Charles M. Brinckerhoff

Everyone -- especially the engineer -- is aware of the great technological and social changes taking place in our world today, We realize that changes have been taking place since man's beginnings on earth, but the element we now face is the speed of change, rather than change itself. Developments in medicine, in transportation, in space exploration, in global communications, and in many other fields, are constantly being made known. These developments are affecting the lives of each of us, although some may appear remote and unrelated to us as individuals. New developments, almost on a daily basis, affect our work as well as our social, religious and educational lives. The effects are immediate and permanent.

Jan 1, 1967

The types of risk to mining projects using environmental protection as justification are examined. In Australia, Governments, whether Federal or State, enforce environmental legislation. The way they do This has an impact on the risk to a project. This is discussed and examples are taken from the Northern Territory uranium industry. Special reference is made to mine closures where the roles are not yet entrenched.

Jan 1, 1994

By Thomas P. Dowling

Historically, laws controlling the manufacture, sale, transportation and storage of high explosives and regulations governing the use of explosives were formulated to prevent accidents or eliminate incidents that might jeopardize public safety. Many of the original laws and regulations regarding classification of explosives and blasting materials, tables of distances for separation and/or isolation of explosives, construction of storage magazines and methods of blasting were based upon empirical data, field experiments or scientific facts. During the past few years, however, it appears that some of the explosive laws and blasting regulations introduced and/or enacted by federal, state and local agencies seem to be based more on political expediency than on factual information or technical data.

Jan 1, 1976

By V. Dinesen

"Grinding is simply the function of reducing particles in size or creating new surface areas. This may be accomplished by many means but we will only concern ourselves with the continuous grinding process as performed in a revolving drum or mill, containing a grinding media. Such a mill consists essentially of a feed head, a cylindrical shell section and a discharge head. To prevent internal wear of these parts it is customary to attach replaceable linings over the wear areas. The specification and design of these mill liners is more important than generally conceded. As they reduce the effective internal volume of the mill, they will consequently affect the whole mill ·design and operation.A number of mill designs of various sizes are available for combined crushing and grinding of materials within a wide size range. For simplif1cahon purposes we will refer 1n particular to conditions relating to standard mill shapes having a length which is greater than the diameter. Such mills usually rotate at speeds between 60% to 85% of the critical speed and may, depending on the grinding media used, be classified as rod mills, ball mills and pebble mills.LINER MATERIALSA great variety of materials have been and are being used for mill linings. These include wood, ceramics and cements, rubber and plastic compounds, rolled and forged steels, cast steels and cast irons, both plain, alloyed and specially treated.The choice of a liner material depends on many factors. In both dry and \\.:et grinding, it may be necessary to consider product purity, colour, chemical reaction etc. but for our purpose we \viii refer to wet grinding operations as generally used within the mining industry."

Jan 1, 1972

By Sharon K. Young

What might an ideal leach-to-cathode/product system look like in the next century? The paper looks at the synergies of the 60's and 70's that led to the highly effective copper leach SX-EW system of the 90's. Standing in the year 2020 focuses on what breakthrough technologies might make possible a next generation leach/extraction/metal recovery system. Many of the pieces of such a technology have been developed, even piloted: in situ leaching, enhanced bioleaching, heap leaching of fine particles, resin in pulp, ion exchange, alternate anode reaction electrowinning, novel anode coatings. With nearly non-existent research on the part of individual large companies, the greatest challenge may not be inventing the technologies but rather inventing an industry "will to create."

Jan 1, 1999

The nature of exploration in Australia is reviewed from its inception to the present time. It is seen as consisting of three phases: the first, prospecting; the second and third, mainly company-based activity. The first yielded the discoveries on which the mining industry was originally built. The great recent growth of the industry has been due mainly to the discoveries of the third. The technical, organisational, legis- lative and other aspects are reviewed. The overall result has been a very great increase in the known mineral resources and, viewed collectively, exploration is seen as providing the principal means of assessing, evaluating and building up the nation's mineral resources.

Jan 1, 1973

By D. L. Watson

In spite of the deflationary state of the minerals business today, there will be opportunities for those who can fulfill future needs. Since there are abundant supplies of ores and fuels to keep prices down, at least in peacetime scenarios, future needs may be as much political and social as technical and economic. Engineers and economists will develop new and innovative ways to find, mine, process and pay for mineral deposits. Pressure from governments and non-governmental organizations and the public will combine with market forces to provide opportunities for highly competitive, risk-taking enterprises who can leverage the qualities of their orebodies and employees by being good neighbors and partners.

Jan 1, 2000

By Clifford J. Lewis, James L. Drobnick

Vexed with competition from relatively high grade foreign orebodies, perplexed by marginal, low grade domestic orebodies, and ironically faced with the fact that practically every metal needed in our economy is available domestically in ample quantity in the ground, our mining industry awaits the advancements in beneficiation technology that will bridge the gap between the ground and the market place for our presently unexploited mineral reserves. Among the vast number of research and development projects underway in the metals mining industry, there are a few chemical techniques in metals winning that, with further development or wider application, could have a profound effect on the industry. These techniques include the Imperial Smelting and Refining Process for complex lead-zinc ores, chlorination and fused salt procedures, the liquid ion exchange process, and the field of non-aqueous leaching. IMPERIAL SMELTING PROCESS The Imperial Smelting and Refining Process is of interest because it offers a possible economic route for the processing of complex zinc-lead-copper ores. The process represents the outcome of the combined efforts of metallurgists and engineers of Imperial Smelting Corporation. Ltd., the United Kingdom Subsidiary of the Consolidated Zinc Corporation, Ltd., and is the subject of patents throughout the world. This process is essentially the employment of the blast furnace for the production of zinc. Zinc has always resisted blast furnace technology, primarily because of the difficulty of condensing zinc vapor from dilute gases. The Imperial Smelting Process employs a blast furnace working at ordinary pressures and in a system which is able to con- dense a blast furnace gas of a very low zinc content.

Jan 11, 1963

By Y. Takahashi, I. Iwasaki, S. Tanabe

Supported by the vigorous capital investment of the heavy and chemical industries and by the ever-increasing demand for durable consumer goods in the past decade, Japan has now emerged as the world's third largest steel producer, surpassed only by the United States and the Soviet Union. In 1968, the crude steel production is expected to exceed 50 million tons; the per capita steel consumption at that time will reach 886 lb, approaching the level of Western Europe. Characteristics of the Japanese steel industry is the high dependence of raw materials on overseas sources. Before World War II the industry relied on North China and Manchuria for coking coal, and on middle China, Hainan Island, the Philippines and the Malayan Peninsula for iron ores. After the war, the major sources of iron ores were shifted to the Philippines and the Malayan Peninsula, supplemented by shipments from the United States, Canada, India and Goa. The United States, in addition, became the primary source of coking coal.

Jan 1, 1967

By A. B. Rossetti

"THE MISSION TO Offshore Scotland was in my opinion a very worthwhile venture, as it indicated the scope of the offshore oil and gas business and how we might exploit it to the fullest here in Nova Scotia - if our offshore fields eventually become producing fields. The writer was able to attend a considerable number of lectures and as a result gained some valuable know-how on the engineering design, financing and operation of the North Sea oil industry. There are many new fields of technology that had to be developed to overcome the North Sea's hostile environment and a great deal of the same technology will have to be developed to win oil and gas from our continental shelf. The visit left me with several impressions, which in the main are:(1) The high order of investment required to develop offshore oil. The investment ranges from 10 to 20 times that required for a similar output on land. Each barrel of oil costs on the average of about $2,- 500 per barrel per day.(2) Because of the high investments required, before the first oil is produced the field must be brought into production at the earliest possible date and initial lead time from decision to production is less than four years. In the British Petroleum field, working at a depth of 450 feet will require an investment of $900,000,000 to develop a production of 400,000 bbl per day. (3) The size and complexity of equipment required is beyond anything ever imagined. Problems which must be overcome are such factors as water depth, wind velocities, wave height, wave period, long periods of darkness, low temperatures, distance from land, and fog."

Jan 1, 1973

By A. F. Peterson

MUCH has been said and written about the engineer shortage. The mining branch in engineering has lagged during the past several decades. I can think of two institutions, formerly prominent in that field, that have discontinued this department and another that has branched from a purely mining school into various forms of engineering. Conversely, I do not recall any institutions that have added mining to their curricula. I believe that this action is in direct response to the demands of incoming students. But I also believe that while there is a specific demand for civil, mechanical, and electrical engineers in the highly complicated mining operations of today, our need for mining engineers capable of assuming top responsibility for mining operations is unchanged.

Jan 3, 1957

A comprehensive, systematically structured mineral evaluation system is a prime requirement for objectively assessing mineral supply impacts on the economy. The Minerals Availability System developed by the US Bureau of Mines is a step in the right direction-a well-organized unraveling of the mineral supply network, structured in format to allow quick retrieval for rapid listing, supply analysis, and other uses.

Jan 9, 1977

By S. G. Vick, K. E. Robinson, W. D. Webb

INTRODUCTION This paper discusses two uranium tailings waste disposal studies that reflect the United States Nuclear Regulatory Commission (NRC) regulatory actions and their changing requirements during the mid to late 1970's. Present guidelines require that all new uranium tailings impoundments be designed and constructed to eliminate, to the extent that it is reasonably achievable, exposures and risks to the public from the tailings. This includes positive measures for control of seepage losses from the impoundment and for control of radiological releases caused by wind and water erosion. Long-term stability of the reclaimed impoundment is also a very important requirement. That is, it is intended that the tailings impoundment, once it is reclaimed, will require little or no care or maintenance as long as the uranium tailings remain a hazard. Principally because of the long-term stability objective, the NRC has now identified subsurface burial of the tailings as the "prime option" for tailings disposal. The environmental implications of these proposed regulatory actions are obviously desirable. The economic implications the actions may have on a particular project are not always so obvious because they are so dependent on environmental suitability of site conditions. Selection of a site with favorable topographic, geologic and hydrologic conditions will usually result in the most economically and environmentally attractive alternative for tailings disposal. The first project discussed in this paper was initiated before the NRC guidelines had been developed to favour subsurface burial. At the beginning, seepage and radon emission control requirements were moderate. Constraints were imposed on the design by site topography, geology, and project capitalization considerations, factors which were dealt with according to straightforward engineering and design principles. More serious constraints were imposed by changing regulatory requirements. Unlike the more usual engineeringrelated constraints, regulatory requirements were upgraded during the design process, causing the design itself to undergo numerous modifications. The second project was initiated after the NRC proposed regulations had become better defined and below grade burial appeared to be the preferred

Jan 1, 1980

By W. C. Spence, Burt C. Mariacher

Methods employed to beneficiate ores utilize relatively few fundamental principles to effect size reduction and concentration. In crushing and grinding only impact and compressive forces with a minor amount of shear are employed. In concentration, gravity, magnetic, electrostatic and flotation constitute the major methods of concentration with minor use of sizing, hand picking and adhesion. This industry, as all others, can expect in the near future to see the development of new techniques for improved efficiency, cost reduction, and exploitation of raw materials hitherto considered unmanageable. NATURAL AND INDUCED RADIOACTIVITY At the Canadian Department of Mines in Ottawa in 1946, C. M. Lapointe developed a picker belt system whereby radioactive ores could be concentrated by electromechanical means. This invention ultimately led to development of what is now refer- red to as the Lapointe Picker and which has been used commercially at Port Radium and Port Hope for the upgrading of jig concentrates. Basically, the system consisted of conveying sized uranium ore on a belt under a radioactivity detection device which in turn electronically operated a kicker or plunger that separated the ore from the gangue constituents. Thus, a new principle for mineral concentration, radioactivity, was introduced commercially.

Jan 7, 1962