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By Paul Piercy

Bougainville Copper Limited operates a porphyry copper mine in Papua New Guinea. The waste dumps will contain 400 to 500 million tomes of rock at the end of nine life. The paper describes investigations carried out over a period of en years and highlights the problems associated with waste lump leaching in a tropical and seismic active region. Aspects discussed include mineralogy, chemical reaction, leaching rates, microbiological activity, dump stability, dump structures, effects of tropical conditions, seismic activity and topography.

Jan 1, 1981

By Wallace W. Wilson

It scarcely 1s possible to read a new issue of any of the principal mining trade journals without noting some mention of a major new overseas mining venture with which one or more domestic companies are involved. These projects seem to follow a fairly consistant pattern; most are large open pit mines, with relatively low grade ore bodies but huge reserves; the total price tag will be in nine significant figures and around half or more of the total cost will be for infrastructure. West1 noted that nearly $7 billion is being invested annually for new mining projects and the expansion of existing mining ventures, in the free world. He anticipates that by the year 1975 such investments would reach the $10-11 billion annual figure, and that in the five year period 1972-76 total capital requirements can be expected to aggregate around $45 billion. The proportion of this total investment which will be financed in some manner is difficult to estimate because of the variety of available financing arrangements. West estimated that around 75% of the total capital would come from internally generated funds, with the balance from external sources. Conceivably a substantially higher percentage could be attributable to external financing, especially it the trend of recent mineral development in Canada and Australia is any criterion, and of course, including local sales of equity as a part of the package.

Jan 1, 1973

By C. V. Baltzer, E. L. J. Bingham

Compliance with the EPA's emerging Clean Water Act regulations can be challenging. Open pit copper mines in Arizona have found themselves in a tangled web of changing rules, regulations, and guidance documents regarding storm water and process water discharges. Large mining properties must come up to speed on a myriad of issues including the definition of zero discharge, what constitutes a process related spring or seep, and tailings and waste rock Best Management Practices. The example of the Pinto Valley Mine in Arizona is used to illustrate National Pollution Discharge Elimination System regulatory issues.

Jan 1, 2001

By William B. Schmidt

In July of 1974 a study team comprised of the authors was formed by the Department of the Interior. It was supported in part by funding from the National Science Foundation. The purpose of this study group was to visit coal mines and research and manufacturing facilities in England and Germany, to review the status of mining in these countries, and to identify mining technology which might have application to U. S. mining conditions. The duration of the visit was 18 days. The first week of the trip was spent in England. Time does not permit a complete recitation of the team's impressions but a few of the more interesting technologic developments will be discussed. These fall into the following categories- High Speed Development Ground Support Chainless Haulage and Face Conveyors Nucleonic Steering of Shearers Miscellaneous

Jan 1, 1975

By L. W. Saperstein

Surface mining of coal is undoubtedly one of the more controversial aspects of the mineral industries today. There is a constant tug between the need for readily available and inexpensive energy supplies and the desire to minimize disturbance to the land. Without a doubt, surface mining severely disturbs the land surface. The duration of this disturbance, from a minimum of a few months to a maximum of infinity, however, is strictly dependent upon the mine operator's willingness to reclaim. Surface mining critics claim that it is impossible to ameliorate the detrimental effects of this mining to insignificance. The more vocal critics, indeed, are calling for complete abolition of surface mining for coal. Thus, they do not believe that it is possible to restore surface- mined land to pre-mining conditions. As a consequence of this position, an adversary relationship has developed between the operators and their critics who, simultaneously, believe they are doing their best for the United States. In a forum of mining experts, there is little need to recount the kind and amount of devastation that can result from poorly reclaimed land. This has been done numerous times, including once 1 by the author. Of particular interest to this paper, though, are the environmental hazards associated with contour strip mining. In addition to the problems of area mining: denudation of vegetation; exposure of toxic spoil; increase of erosion runoff; etc.--contour mining has the very real problem of landslide due to the outslope stacking of overburden. Contour mining is understood to be the extraction of coal from a hillside outcrop such that the resultant pit follows, or nearly follows, an elevation contour. The problem with contour mining as usually practiced is that the spoil from the cut, or the first cut if multiple cuts are made, is placed on the outslope. If this slope is steep, the resulting pile is difficult to stabilize, generally erodes swiftly, and may fail disastrously.

Jan 1, 1973

By Felicia F. Peng

An economic analysis for evaluating coal preparation plants in the Appalachian Region is presented. A complete coal preparation plant which includes multi-streams and/or multi-stages coal cleaning circuits, complete closed water circuits, environmentally acceptable refuse disposal and reclamation systems is used to determine the capital and operating costs. The plant is capable of producing metallurgical grade clean coal or deep cleaned steam grade coal for future power generating plants use. Utilizing a profit maximization as a decision criterion, an optimal yield, and optimal coal clean¬ing circuits, closed water circuits, and disposal and reclamation systems for a given coal characteristic may be selected among the process alternatives by using a process simulation-economic model of the coal preparation plant. A deterministic analysis is used to calculate the discounted-cash-flow interest rate of return (DCFIROR) and project the selling prices, and determine the Return on Investment (ROI) for the cases of 32.65% and 52.74% plant utilization with producing two cleaned products. Sensitivity analyses are performed to quantify the effect of total capital investment, operating cost, run-of-mine cost and yield on an economic criterion-ROI and selling prices. A probabilistic evaluation using the Monte Carlo simulation technique is further made to quantify the risk involved in obtaining the desired profit levels. The results of the economic analysis for a given coal preparation plant configuration and characteristics of raw coal indicates that the selling prices of producing two cleaned products are greatly affected by the change in percent of plant utilization (production schedule), yield, and run-of-mine cost, and total capital cost. The sensitivity analysis also shows that the total capital investments has a three times greater effect on required selling prices than operating costs. The risk analysis shown that the overall economics look very attractive with current coal sale prices and 52.74% plant utilization.

Jan 1, 1979

By M. J. Gula, S. S. Xue, E. P. Horwitz, J. T. Harvey

A study has been conducted to control iron in copper electrolyte streams using Eichrom Industries’s new Monophosphonic /sulphonic acid resin. The resin strongly and selectively extracts ferric ion over copper and cobalt from highly acidic copper electrolytes. The resin has a loading capacity of 27 g/L of iron and can be readily regenerated. In addition, the new resin can be easily synthesized using commercially available starting materials. This paper presents the experimental results for iron control in copper electrolyte streams using the new resin and discusses its potential applications to other hydro-metallurgical streams.

Jan 1, 2000

By G. E. Erdman

The total attitude of the industrial minerals producing company is a most important factor in how they regard quality control, technical support for their customers, and procedures used in mining their minerals products. This philosophy of the producing organization directs their action along certain courses. For instance, one producer might see itself as a mining company with its major goal mining efficiency to make it exceedingly price competitive in the market place. Another producer might see itself as a wide spectrum multi-mineral producer that furnishes a reputation for a complete line of products. Another producer might see itself as a specialist in one specific industrial mineral and bet its whole bankroll on providing the very best of quality with the goal of becoming the largest producer of the mineral commodity. Each perception can have a different impact upon the producer's operations and its regard for quality control. Minerals Being Produced The specific markets being served will have their own influence on how mineral product quality is regarded. Ceramic raw materials, for instance, have a very low tolerance for iron which is the cause of low fired color. Thus, industrial minerals for use in glass and ceramic markets must be won from deposits with a very low iron content. A high iron silica sand might be sold to a manufacturer of good old beer bottles. That is a solution to one particular quality facet, but eliminates selling to a significant market in clear glass, porcelain enamel, ceramics whiteware bodies and hobby glazes. Thus, there is a need for sound research in the industries expected to be served before the product is brought to market.

Jan 1, 1987

By James E. Lonergan

Linear goal programming is a multi-objective optimization technique where the constraints of a linear programming formulation of a problem are considered as additional objectives. The optimal solution is the one that comes closest to satisfying all the objectives. An interactive computer program was written to utilize this technique in solving the feed blending problem faced by power plants de- pendent on multiple sources of coal supply. This program determines the amount of coal from each supplier to utilize in the blend. Examples of the use of the program in both long and short term coal procurement planning scenarios are given.

Jan 1, 1984

By Merih Celasun

The literature in operations research centered on mineral exploration has been comparatively limited in view of the significant implications of mineral discoveries upon the national economies in general and mineral industries in particular. Much of what has been published is of somewhat unsure academic nature, indicating to a certain extent the scarcity of industrial applications. Mineral exploration activities present quite difficult operational and conceptual problems. The purpose of this paper is to discuss the principal characteristics of decision problems encountered in planning an exploration program, to indicate an optimization approach to a certain class of allocation problems, and to suggest directions for future research effort.

Jan 1, 1962

By Thomas G. Langton

The demand for mineral raw materials, especially in the major industrialized nations, has grown rapidly during the past three decades. One consequence of this growth has been an increasing reliance by the large industrialized countries upon nondomestic mineral supplies. These mineral supplies, to a large extent, have been developed by capital from the major industrialized countries. Until recently, most foreign mining ventures were either wholly-owned subsidiaries or joint ventures between two or more mining companies. The recent rise of economic nationalism has substantially changed the business climate and parameters under which foreign investors operate. This paper describes some of the underlying reasons for this change and notes how investors have adapted to the new business conditions.

Jan 1, 1974

By Douglas E. Hansen

A current trend in blasting of large volumes of rock is to use increasingly larger diameter shot holes. The use of large diameter holes meant; correspondingly large explosive charges will be loaded and detonated, and, if special efforts are not made, will result in more damage and vibration beyond the intended blast area. With the rising awareness of environmental factors, vibration control becomes increasingly important. Equally important is the preservation of intended lines and grades, and in some cases by blasting with care, slopes can be safely steepended. In the past, vibration control was established to prevent damage to man-made structures. The quarry or open pit itself can be regarded as a structure composed of rock. Far too little attention has been given to the effects of blasting on rock walls. The primary purpose of blasting is to break rock. If the integrity of the rock has been destroyed beyond intended lines and grades, the excavation will be more costly than originally anticipated. The increased cost will not only be from in¬creased excavation due to overbreak, but also increased maintenance due to blast induced wall instabilities

Jan 1, 1976

By R. L. Pozzo

A previous investigation showed that corrosion currents estimated from polarization curves for the pyrrhotite-grinding media system under abrasion correlated well with corrosion currents estimated from marked ball wear test data by applying the Faraday's Law. Freshly abraded metal debris were magnetically attracted to pyrrhotite and lowered the rest potentials of the mineral particles, thereby affecting the corrosive wear. The investigation was extended to explore the interactions between a nonmagnetic sulfide mineral, pyrite, and abraded metal debris and their effects on the corrosive wear mechanism. The electrochemical behavior of a three-electrode system involving pyrrhotite, pyrite and grinding media was also investigated as a first step towards elucidating the nature of interactions that occur in the grinding of complex sulfide ores.

Jan 1, 1987

By S. K. Kawatra

In this paper three methods of on-stream analysis 1) Radiometric techniques, 2) X-ray tube techniques and 3) Neutron activation method are reviewed. Advantages and disadvantages of each method are discussed.

Jan 1, 1984

By G. K. Derby

Paper presents project results investigating current techniques for dragline wire rope removal and the development of less hazardous means of performing the task. The cannon is the most prevalent method used in American surface mines. A cannon test program was conducted that used 40-and 50-grain primer cord to establish force produced using a 56-pound projectile. Socketlwedges were separated to establish separation force data. Two alternative removal methods, pendulum ram and portable hydraulic pusher, were developed and tested. Both provide sufficient force to effect separations under normal conditions on draglines with up to 78- cubic yard buckets.

Jan 1, 1984

By Paul R. Thomas

This paper addresses two issues affecting the international ferrochromium market as they pertain to the changing pattern of U. S. chromium import dependency. These issues are 1) the long-term ferrochromium production cost differential between the United States and the Republic of South Africa and 2) the ability of Zimbabwe to expand ferrochromium production and exportation. This paper draws upon the data and analyses of a recent Bureau of Mines Minerals availability Program appraisal that evaluated the international availability of chromium in the form of chromite and ferrochromium from 10 market economy countries. South African ferrochromium producers are shown to have a long-term production cost advantage over U.S. producers of $0.03 to $0.04 per pound of contained chromium, in 1981 dollars. Zimbabwean ferrochromium production and exportation are expected to increase in the future. Major expansions of production capacity will be dependent upon alleviating potentially serious constraints in electric power, rail, and port facilities. In the long term, ferrochromium production costs in Zimbabwe are expected to increase faster than the rate of inflation, because as chromite mining from the podiform resources in Zimbabwe decreases, production from the Great Dyke resources will increase.

Jan 1, 1984

By Velu Annamalai

In-situ uranium solution mining involves the injection of a lixiviant (leach solution) through appropriately placed wells into the underground ore zone. Upon contacting the uranium minerals, this solution will dissolve the uranium. The uranium containing solution is then pumped out of the wells into a processing plant where the uranium values are removed, typically in ion exchange columns, and the stripped liquor is recycled back into the field. The lixiviants may be acidic or basic. Where the ore zone mineralization contains appreciable carbonate, as in the South Texas fields, acid consumption would be excessive and the typical solution is ammonium carbonate bicarbonate at about 5-10 g/l and a pH of 7-9. Because the usual uranium minerals, uraninite or coffinite, contain uranium in the insoluble tetravalent state, it is necessary to add an oxidant to increase the valence to the hexavalent state where the uranium is soluble. Oxygen dissolved in the lixiviant has been shown to be quite effective for this purpose. It is also much more economical than other oxidants. Of concern is the possibility that (1) its solubility may or may not provide concentration levels adequate to give an economically attractive uranium level in the extracted liquor, and (2) the addition of oxygen in excess of the saturation level so as to increase the uranium grade in the lixiviant may cause gas blockage of the typical fine-pored ore formations.

Jan 1, 1981

By Thomas A. Mekelburg

Due to a tight ash constraint on the clean coal product and difficult middlings washability characteristics, a considerable amount of coal was being lost in the jig middlings at the Monterey No. 2 Mine. An investigation was conducted into circuitry to recover this lost coal with minimal effect on the total clean coal ash. A reverse two-stage hydrocyclone system cleaning at low specific gravities was selected. This system is currently recovering approximately 5.8 kg/s (23 tph) of 11.5% to 12.5% ash coal. The specific gravity of separation for the system is about 1.5 and the probable error is 0.13.

Jan 1, 1984

By L. L. Oriard

There are certain site-specific geological and physical features of a rock mass which control its behavior under the dynamic stresses induced by the action of explosives. It is essential that blasting technology be adapted specifically to those features. There does not exist a single, simple "right" way for each type of blasting operation, but rather each operation must be custom-designed for each site. When this is done, it is often possible to produce unusual but highly desirable end resglts, such as undisturbed narrow rock walls, monoliths and square benches. Although the techniques illustrated here were developed specifically for "sculpture blasting", the geomechanics principles would apply to other types of blasting control, both large-scale and small-scale. Because the techniques are designed more for the purpose of modifying the site responses which would ordinarily be expected than they are to developing new "blasting formulae?, the name "Modified Site Response Blasting" will be used.

Jan 1, 1984

By Nick Barton

The ability to estimate that support is unnecessary for various dimensions of opening in certain rock mass environments is of particular relevance in the mining industry, where most excavations are not expected to remain open indefinitely. As Hoek1 observes: "the basic aim of any underground excavation design should be to utilize the rock itself as the principal structural material, creating as little disturbance as possible during the excavation process and adding as little as possible in the way of concrete or steel support". Approximately two hundred case records have been analysed for the purpose of determining the amount of permanent support normally used when a given span is excavated in known rock mass conditions Some thirty cases concerned unsupported openings. Excavations that can stand unsupported appear to have certain common characteristics as regards rock mass quality. However, the mechanical properties of the rock mass are not the only factors controlling the choice of design. The dimension of the opening (span or height) and the type of excavation are two important variables.

Jan 1, 1975