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By George Dials

Good morning gentlemen. My name is George Dials, and I am [vice] president of the Mining and Reclamation Council of America (MARC). The Council is composed of various companies, individuals, and affiliated state and regional trade organizations representing nearly 3,000 companies directly and indirectly involved with surface coal mining in the United States. I am very glad to be here today to address the Society of Mining Engineers of AIMS. While I do not pretend to be an expert in either geological or geotechnical engineering, I am infinitely familiar with the provisions of the Surface Mining Control and Reclamation Act of 1977 (P.L. 95-87) and the Federal regulations that have been promulgated pursuant to that Act. The Office of Surface Mining Reclamation and Enforcement (OSM) was created by P.L. 95-87 within the responsibility for implementing the provisions of the Act and "to ensure that society and the environment are protected from the adverse effects of surface and sub-surface coal mining operations."

Jan 1, 1979

The primary use of coal in the US is for electric generation. The problems associated with the use of this vast amount of coal is the central theme of these sessions. The problems discussed include: production capacity, mining problems, coal cleaning, transportation, combustion, and various environmental problems, such as health effects of coal combustion, water and air pollution, and solid waste disposal.

Jan 1, 1979

By M. M. Tilman

Etchants containing hexavalent chromium and sulfuric acid are used in a variety of surface-finishing operations. When the resultant spent solutions are discarded, substantial quantities of chromium are lost and pollution prob¬lems are created. To minimize the undesirable environmental effects while improving metal and minerals recycling technology, the Bureau of Mines is con¬ducting research on a method for the economic inplant recycling of these waste etchants. Trivalent chromium, produced when the etchant reacts with a substrate, is oxidized in the anode chamber of a diaphragm cell; other metals, dissolved during the etching operation, are transferred to the catholyte. When waste brass etchants are treated in this manner, all of the trivalent chromium is oxidized and more than 40 percent of the copper and zinc is removed. Similar copper removal and chromium oxidation are achieved with waste printed circuit board etchants and rinse waters from plastic etching operations. The electrical energy needed to regenerate 1 kg sodium dichromate is less than 9 kwhr. Regenerated brass etchants evaluated by two companies equaled or exceeded the performance of fresh etchants.

Jan 1, 1979

By D. M. S. Bhatia

Five sulfide minerals from the Magiwnt mine, southeast Missouri were analyzed for 31 trace elements in over 300 samples by laser microprobe spectrographic analysis of polished sections. The concentration of several trace elements shows a pattern of progressive variation with depth (space) and variation with different paragenetic stages (time) of each mineral. Factor analysis of the geochemical data shows sympathetic correlation both in space and in time of Bi, Cd, Ge, and Sn in galena and sphalerite, and Ni and Co in sphalerite and marcasite.

Jan 1, 1979

By T. D. Wheelock

The effect of various flotation depressants and surface treatments on the floatability of coal derived pyrites in the presence of XIBC was investigated with a modified Hallimond tube microflotation cell. The floatability of pyrite particles which had been cleaned with hot dilute (5%) hydrochloric acid was relatively large. However, the floatability of such particles was reduced greatly by the addition of specific depressants such as calcium hydroxide and also by treating the pyrite with an aerated warm alkaline solution. Although this treatment and these depressants also had some effect on the floatability of coal particles, the effect was much less than on the pyrite particles.

Jan 1, 1979

By T. G. Carnahan

The Bureau of Mines investigated a flotation-nitric acid leach procedure as part of the goal to maximize minerals and metals recovered from primary and secondary domestic resources. Studies were conducted on an ore that contained carbon-bearing and sulfide mineralization that rendered a portion of the ore refractory (resistant) to conventional leaching technology. The procedure investigated for treating the ore consisted of the following: (1) separation by flotation of the carbonaceous and sulfidic components from the ore, (2) leaching the flotation concentrate with nitric acid at 100° to 110° C, (3) leaching the flotation tailings with sulfuric acid, and (4) processing the combined leached slurries in a conventional manner to recover yellow cake. In step 2, HN03 is converted to gaseous products from which it is regenerated by reacting these products with air and water for further leaching. An overall uranium extraction of 96 pct was achieved by this procedure.

Jan 1, 1979

By Michael A. Toole, O&apos

INTRODUCTION The tremendous capital investment required to produce a low grade ore deposit demands a reliable answer to the question: "How much does it cost to drill a well to produce the uranium that geologists have indicated is there in the ground?" However, you will find the answers given will be many and varied, depending on whether they come from the operating company, the drilling contractor, a geologist, a reservoir engineer, purchasing agent, or whoever. Each generally considers only a limited area of the total operation. The operating company usually depends upon the drilling contractors, service companies, and consultants to supply expertise. Because it is often difficult to see the "whole picture" or even to agree upon what the "whole picture" is, planning a well program and its costs is often done piecemeal. Frequently, costs "saved" in one area of the program are needlessly spent in another, because the effect of one area upon the other was overlooked. Since the drilling fluid is such an influential part of the drilling program, it should be given utmost consideration when planning the overall program. As W. D. Lacabanne wrote in 1954: "The drilling fluid system is understandably called the heart of the rotary oil drilling rig. Any other type of rotary rig.... should benefit by the incorporation of mud fluids in the drilling scheme." And G. R. Gray mentions that "The driller recognizes the drilling fluid as one of the useful tools available to solve drilling problems." However, in minerals drilling, only in recent years has the drilling fluid been considered as more than a tool to get through special problem areas. Although there are many similarities between drilling for oil and gas and drilling for minerals, the differences in the drilling equipment used justifies designing specific fluids for the minerals drilling industry. NL Baroid/NL Industries, Inc. has been a leader in introducing such fluids and in providing technical know-how to the minerals drilling industry. The purpose of this paper is: (1) to discuss the selection of drilling fluids to meet specific drilling conditions during both exploration and production and (2) to show the interrelationship among factors present in the exploration and production phases that influence total well costs. DRILLING FLUIDS FOR DRILLING PROBLEMS The drilling fluid is a tool that can be used to improve drilling performance by improving hole cutting, cleaning, stability, and formation productivity. Properly formulated and maintained drilling fluids enable the drilling operation to be carried out with increased efficiency and lower total (overall) costs. However, it should be noted that not all drilling problems can be solved by even the most carefully prepared and maintained drilling fluids. Of the many possible drilling problems encountered in a well before reaching target depth, this paper will discuss only those most likely to be present in the shallow [61 to 610 m (200 to 2000 ft)] drilling operations in South Texas. LOST CIRCULATION Loss of circulation is the most common problem encountered in drilling. Because the losses occur under varied conditions, it is often difficult to determine the exact causes. "Lost circulation" or "lost returns" means the partial or complete loss of drilling fluid to voids in the formation. "Loss of water" while drilling with water may take place into any permeable section and should be distinguished from "water loss" or filtration of fluid through the filter cake of mud solids laid down on a permeable formation. "Loss of water" can frequently be stopped by the addition of colloidal sized clay particles such as high yield bentonites, whereas "water loss" may be controlled with organic polymers. Subsurface conditions that lead to loss of circulation can be classified as: (1) natural fractures, (2) induced fractures, (3) unconsolidated or highly permeable formations (loose gravel), and (4) cavernous formations (crevices and channels). Loss of circulation may occur whenever the borehole pressure exceeds the formation pressure. The greater the differential pressure, the more likely it is that circulation may be lost. To stop loss of whole mud, voids must be bridged so that a filter cake can be laid down on the permeable section. The plugging material must be of the proper size and shape to offer greater resistance to the fluid flow around it than the flow up the annulus. A plugging composition that satisfies these requirements may not be able to be handled by the small rig pump available.

Jan 1, 1979

By Robert R. Dorfler

We ought not look back unless it is to de- rive from past errors, and for the purpose of profiting by dear bought experience. - George Washington During the mid 1960's, the application of automation was introduced to Climax by two process control companies. In 1969 Climax decided to seriously consider improved control of selected areas of their milling process after preliminary research had been completed on two rougher ball mill grinding circuits. In 1971 the Climax Mill Department developed a direct digital control scheme for rougher milling, designed a remote control center for handling process water, planned to automate the central steam heating facility for energy conservation, and convert other plant areas to automation. All twenty rougher grinding mills and the industrial water system were automated by 1977. The idea of automating central heating and other areas was abandoned although some fuel conservation items were installed at the heating plant. During this period from 1971 to 1978, the mill capacity was expanded from 39,000 metric tons per day to 43,000 metric tons per day and cyclone classification was introduced to rougher milling. Ore quality changes degraded the milling recovery from over 90% to less than 85%. This report describes the procedure the mill used in developing the automatic process and the occurances that affected the timing and fina1 control logic. The report deals primarily with the automation of the ball mill grinding, classification and flotation process as this was the bulk of the seven-year project.

Jan 1, 1979

By Isobel Clark

The problem of the estimation of ore reserves is essentially a simple one to describe. Given a set of sample data, at specified locations within a deposit, how can we estimate the value (or quantity) of ore in unsampled areas. The question may be posed of a whole deposit (global) or it may be more desirable to estimate smaller volumes within the planned mine area, e.g. stopes or blocks (local). Many methods have been evolved to tackle this problem, from hand-contouring of values by the mine geologist to extremely sophisticated geomathematical analysis. The main difficulty with any estimation method in this context is that it is almost impossible to check whether the "predicted" value bears a close relationship with the "actual" value. The only reliable way to decide if an estimation method has "worked" is to test the eventual value of ore against the predicted value. This is, more often than not, impossible - even allowing for the time factor involved. To know the "actual" value of a mined block it has to be sampled intensely, and these values with their positions recorded accurately. Alternatively, blocks may be passed through the concentration process individually and these results recorded. In most producing mines neither of these alternatives are practicable or seen to be-important. Another problem with comparing in-situ (so-called) mineable reserves with production figures is the introduction of many variables into the concentration process -- dilution, wastage, possible stockpiling, mill recoveries and so on.

Jan 1, 1979

By S. Venter, W. E. Stumpf

Some of the factors that govern the choice of a nuclear fuel are briefly discussed, special reference being made to the introduction of advanced carbide fuels into fast-breeder programmes. One of these factors, i.e. the compatibility of carbide fuels with stainless-steel cladding, is discussed in depth. A very sensitive technique for the study of compatibility interactions between fuel and cladding is described in respect to the effects of particle size, specific surface area and surface oxidation of the fuel,and microstructure of the cladding on the compatibility behaviour of the cladding with the fuels. Finally, the need for the development of modified or stabilized uranium carbide fuels is discussed, and some results are presented to show the effects of small amounts of sulphur in these fuels on their compatibility with stainless-steel cladding materials.

Jan 1, 1979

By Clifford C. E

The Black Star and Racecourse orebodies below 15 level contain a major portion of the primary silver-lead-zinc ore reserves of 56 million tonnes at 150 g/t Ag, 6.4% Pb and 6.5% Zn at Isa Mine. Extraction from this area is scheduled to begin in the early 1980's. Mining in this block will be quite com- plicated as the ore is contained in a dozen separate orebodies varying in width from 3 m to 20 m with only narrow barren pillars between them in some cases. Mining objectives which consider metal recovery, costs, environmental and safety factors, operating requirements and rock mechanics are used to compare proposals. The planning work involved in formulating mining proposals considers disposition of reserves, scheduling factors, sequence of extraction, extraction methods, haulage set-up and ventilation requirements.

Jan 1, 1979

By T. E. Bernard

The CO2-absorbent canisters used in four approved rescue breathing apparatus were investigated. A breathing machine was used to simulate human expiration with gas flow rates of 26, 37, and 48 1/min of 3.5% CO2 in air. The exit gas CO2 concentration, the pressure drop across the canister, and the exit-gas temperature were monitored. The absorbent capacities of the packed-bed canister designs were found to be dependent on flow rate within the range studied, while the capacities of the other designs were less affected. The radial canister had the least resistance to breathing while the complex bed design proved to be the most effective in utilization of the chemical. The overall results indicated that LiOH (lithium hydroxide) has the highest capacity for CO2 absorption among the absorbents tested. It can be used in a simple packed-bed design while maintaining acceptable levels of resistance and exit-gas temperature. Examination of oxygen supply with respect to CO2-absorption capacity suggested that it is desirable to closely match CO2-absorption capacity with the avail-able O2 supply to minimize the size and weight of rescue breathing apparatus.

Jan 1, 1979

By A. L. Mular

Optimization has been defined as the procedure of locating the best of something or the best way of doing something (Mular, 1971). Several texts (Himmelblau, 1972; Ray and Szekeley, 1973; Box and Draper, 1969; and Lee, Adams, and Gaines, 1968) on the subject are available. Such techniques have been placed in two categories, namely, off-line optimization and on-line optimization. For the former, an optimization model is employed; for the latter, a black box approach is involved. The essence of an optimization problem becomes obvious, when a response surface is considered. Suppose that a response (in this case, a criterion of improvement such as profit per day; grade of concentrate per day) denoted by Y, depends only on two variables, X1 and X2, which can be manipulated and controlled. The relationship between Y, X1 and X2 may be represented graphically as shown in Fig. 1. The diagram is called a response surface and its height, Y, is determined by X1 and X2. Points associated with equal responses constitute response contours. The shape is that of a hill, and optimization is the procedure of ascending the hill to reach the top (maximum). In practice, a response surface is subject to disturbances which distort its shape and shift its location from time to time, so that the exact location of a maximum is imprecise. Generally, constraints (restrictions of some sort) on responses and manipulable variables serve to define a region of permissible operation.

Jan 1, 1979

By H. Wesley Peirce

Although not generally recognized, Arizona has rock salt deposits unique in the United States. This uniqueness stems from a combination of two factors: (1) relatively youthful geologic age and (2) nonmarine origin. Although Arizona shares one deposit with Nevada (Figure 1, No. I) there are three others within the State (Nos. 2, 4, 5) that are believed to be both late Cenozoic in age (less than 15 million years) and nonmarine in origin. The only other recognized nonmarine salt deposits in the U.S. are much older, being in the early Cenozoic (Eocene) Green River Formation of Colorado and Wyoming. According to Johnson and Gonzales (1), the remaining rock salt deposits in the United States are marine and either Paleozoic or Mesozoic in age. Of the seven localities shown in Figure 1, six in the Basin and Range geologic province are believed to represent nomarine late Cenozoic phenomena and one (No. 7) in the Colorado Plateau geologic province is Paleozoic (Permian) in age and marine in origin. The following comments are intended to update the general geologic highlights of these deposits and to summarize the nature of their present utilization.

Jan 1, 1979

By Roderick K. Davey

Introduction in any business, it is essential that we select those alternatives which are not only technically feasible, but will be the most profitable to the business m terms of corporate objectives Some of the studies and activities requiring support of financial analysis to select the alternatives which most closely satisfy the management objectives and technical considerations are as follows 1 ) Cutoff grade determination. 2) Ore reserve estimation. 3) Production forecasts (long- and short-term) for an operating mine, development of a new mine, or expansion of an existing mine. 4) Evaluation of haulage alternatives. 5) Evaluation of equipment.

Jan 1, 1979

By Ken J. Richards

Industries dependent on pyrometallurgical processing generally find themselves facing a common set of problems, namely, serious environmental restrictions, heavy capital requirements for new facilities and for plant modernization, the certainty of rapidly escalating fuel costs, and the uncertainty of fuel availability. To remain competitive, it has become clear to industry that a new dimension of attention must be given to assuring the maximum performance from plant facilities already in place and from those that are built in the future. In the last decade or so, in response to these needs, there has been an acceleration in the development of new pyrometallurgical process concepts. Their application, though spotty, is increasing. A common factor in this developing base of technology is the need for effective process control. Digital control is an indispensable element of meeting the challenge. We cannot make the point, however, by looking to a general survey of instrumental control of pyrometallurgical processes. Computer control is in its awkward adolescence. Its application is so new that only isolated applications can highlight the trends. For this reason, the authors have chosen to focus on the nonferrous smelting industry to illustrate the status of pyrometallurgical processing and control. We believe this approach will best meet the interests of most readers of this edition and the background of the authors.

Jan 1, 1979

By Edward R. Rose

This paper summarizes and emphasizes the potential importance of Canadian rare-earth occurrences, and recommends that efforts to locate and evaluate rare-earth deposits should be increased. Increasing world markets, depending on intensive applied research into the numerous unique and remarkable chemical and physical properties of the rare-earth elements (REE), are developing; their properties and uses are becoming better known; methods of separation are much improved. The REE group comprises a Cerium (Light) subgroup of 7 metals and an Yttrium (Heavy) subgroup of 9 metals. REE are trace elements in many rocks and minerals, and major constituents of more than 50 rare-earth minerals, many of which are difficult to detect and identify. They occur preferentially in acidic and alkaline igneous and metamorphic rocks, including carbonatites, as well as in placer deposits, certain uranium deposits, phosphate rocks and others. The main ores now are bastnaesite (in Precambrian carbonatite), monazite and xenotime (in Recent beach sands) as well as uraninite and brannerite (in Huronian quartz-pebble conglomerate) and loperite (perovskite) and apatite (in alkaline complexes). World resources are summarized. Twenty mines in 1973 produced an estimated world total of about 31,000 tons of contained rare-earth oxides (REO), 19,341 tons of which came from one mine at Mountain Pass, California. A selected fifteen, of 315 or more Canadian occurrences, are briefly described and compared, and their relative merits indicated. Their abundance and variety suggest the possibility of finding high-grade deposits in many geological terranes in Canada.

Jan 1, 1979

By G. H. Walrod, J. M. Mutmansky, Y. J. Wang

The selection of a shaft size for ventilation purposes is a classic problem of concern to mining engineers. This presentation is concerned with the sizing of conventionally-sunk circular shafts with concrete or shotcrete linings. Costs of sinking shafts of three different depths, from 150 m to 300 m (500 ft to 1000 ft), and six different diameters, from 4.27 m to 7.32 m (14 ft to 24 ft), were obtained through questionnaires to shaft contractors. The primary objective of the economic model presented is the balancing of detailed annual capital and operating costs to achieve the minimum overall cost of the shaft installation over its life. The economic model is similar to previous analyses but treats several of the individual cost categories in an updated fashion. Included in the paper is a detailed analysis of the effects of varying power costs on optimal shaft size. Also included are a statistical analysis of current shaft costs and comments on the choice between shotcrete and concrete linings.

Jan 1, 1979

By Gregor de Ratmiroff

Field prospecting for bauxite in Venezuela has had a long but interrupted history having till now oferred but evidence of occurrences. The Venezuelan Government, trough the Corporación Venezolana de Guayana (C.V.G.), in 1974, formalized a major effort in prospection for bauxite in the Shield area and the Orinoco Delta in orden to establish the possibility of raw material supply to an upcoming and expanding aluminium industry. The Corporation, in turn, created and delegated to the Division of Geological Stu- dies, the formulation of the necessary infrastructure and execution of work in orden to determine the existence of economically exploitable bauxite deposits.

Jan 1, 1979

By Larry B. Bramlett

Regional radiometric, magnetic and geologic data point to Copper Mountain as an area of general uranium favorability. Sub-regional radiometric and magnetic data direct interest to a specific section of an overthrust Precambrian granite. Detailed magnetic and resistivity surveys in this area show local targets of interest, one of which corresponds to Rocky Mountain Energy's North Canning deposit. On the basis of these data a second and previously untested target was drilled resulting in the intersection of uranium horizons similar to those at North Canning. This integrated geophysical approach can be used for uranium exploration in geologically similar areas.

Jan 1, 1979