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By Elizabeth G. Baglin

Research was conducted by the Bureau of Mines to determine the feasibility of using electrokinetic densification to dewater Bayer process red mud, magnetic black mud prepared by pressure digestion of red mud in the presence of ferrous sulfate, and magnetic black mud formed by simu-lated Bayer digestion of Jamaican bauxite with added ferrous sulfate. Tests showed that the solids content of presettled muds could be increased from 25 pct to approximately 40 to 48 pct by gravity draining followed by electrodewatering for approximately 48 h. Electrodewatering may not be practical because of increased reagent and processing costs and because the muds must be thoroughly washed prior to electrodewatering to remove dissolved ions and decrease mud conductivities.

Jan 1, 1988

By M. Leroux, C. J. Martin, S. R. Rao, J. A. Finch

"The effect of nitrogen on the flotation separation of sulphides from complex ores from Brunswick Mining and Smelting (New Brunswick) and Mattabi Mines (Ontario) was investigated. The most significant finding was enhanced pyrite floatability after as little as 3 minutes nitrogen conditioning. This was used in a novel sphalerite/pyrite separation process developed on the Brunswick ore. After aeration and Cu/Pb bulk flotation in air using xanthate the slurry was nitrogen conditioned, xanthate added and the pyrite floated in nitrogen. As an example up to 70% pyrite recovery with about 20% sphalerite recovery was achieved. Sphalerite was recovered from the pyrite tailings and the pyrite concentrate by copper-activation, raising the pH to 10 and floating in air. About 65-70% recovery at 35-40% Zn grade was achieved compared to 25% Zn grade by the conventional route. The process offers a promising alternative to current practice which seeks to depress pyrite at all stages. A possible mechanism of the effect of nitrogen is presented. INTRODUCTIONUse of gases other than air in froth flotation has been reported from time to time. [Podobnik and Shirley, 1982; Lin and Metzer, 1975]. Of all the gases, nitrogen would appear to hold the greatest practical promise because of its easy availability and chemical inertness. It is used in froth flotation in chalcopyrite-molybdenite separation [Redfearn, 1983]. The use of nitrogen in polysulphide chalcopyrite. this case is mainly to reduce the oxidation of a compound (Nokes reagent) used as a depressant for There is no reported use of nitrogen in the flotation of other sulphide minerals."

Jan 1, 1988

By J. A. Finch, G. Labonté

"A long-standing objective has been to obtain interpretable measurements of the oxidation-reduction potential in mineral slurries. For this purpose several sensing electrodes (black platinum wire, platinum foil and spiral, gold foil and spiral, and sulphide minerals such as chalcopyrite and galena) were investigated to determine their response to the presence of sulphide minerals in the pulp, and to the addition of reagents commonly used in flotation. The observed discrepancies between the electrodes may be explained using a combination of the classical mixed potential model for complex solutions and the probability of contact between the mineral particles and the sensing electrode. It is shown from laboratory testwork that gold spirals are preferred over platinum electrodes. Finally, some of the practical aspects of using the electrochemical measurements in a plant environment are discussed.IntroductonThe interpretation of flotation of sulphide minerals in terms of electrochemical (electron transfer) processes has brought new possibilities for process control of selective flotation. Investigations on massive and compacted particulate bed electrodes have shown that the flotation of a given mineral in the presence of a collector can be controlled by the potential induced on the mineral surface. Also, phenomena such as collector less (self-induced) flotation, activation by heavy metal ions, and natural selectivity sustained by galvanic coupling during flotation might also be controlled by electrochemical means.The technique for measuring electrochemical potential in slurries is an adaptation of that used for solutions. The measurement of the oxidation-reduction potential of a solution (ORP , Redox, Eh) is usually carried out by immersing a noble metal electrode (platinum, gold or silver) and a non-polarizable reference electrode: Standard Hydrogen Electrode (SHE), Standard Calomel Electrode (SCE), or silver/silver chloride (Ag/AgCl) in the solution. (The abbreviation Eh implies the SHE is the reference electrode.) The potential difference between the two electrodes is measured using a high impedance electrometer. ASTM standard D 1498-76 (revised 1981)(1) covers the practical details of such measurements; however, it does not deal with their meaning either in complex solutions or in mineral slurries ."

Jan 1, 1988

By J. D. Patsey, G. T. Lineberry

Introduction A computer program was developed for analyzing drum-type hoists before modifying an existing system or designing a new one. Its use permits the preliminary evaluation of a system before seeking technical assistance from mine hoist designers and manufacturers. The user-friendly program accepts a variety of data and analyzes hoisting systems for any balance state. The program can be used to calculate skip capacity to yield a desired production rate, solve for drum face width, select a permissible wire rope, estimate total horsepower of the hoist plant, and estimate annual power cost. Whether required for a large mining complex or for a relatively small operation, a hoisting system must be carefully designed to ensure the efficient, reliable, and safe flow of material. Because shaft sinking and hoist installation can total between 2.5% and 3% of the cost of opening a deep mine, proper hoist selection is critical. Today's mining engineer has at his disposal the most powerful design and analytical aid ever, the micro- computer. There is, unfortunately, limited software for the study of hoisting systems, unlike that for other materials handling equipment (Manula and Albert, 1980; Prelaz et al., 1964; Bucklen, 1969; Thompson, 1985). HOIST reduces a time-consuming set of calculations to a concise package of interrelated subprograms. A literature review revealed no common-user pro- grams to analyze hoisting systems, although at least four major hoist designers/manufacturers/installers have their own in-house programs. To provide a tool with which the mining engineer could preliminarily analyze a materials hoisting system or could check the calculations of a hoist contractor, a computer program was developed. HOIST was written in BASIC for the IBM-PC for ease of program adaptation and to en- courage field use on compatible systems. Details of program development are omitted, since the basic principles of hoisting analyses are relatively straightforward, simple, and readily accepted (Har- mon, 1973; Nordberg, n.d.; Adler, 1957). Program features, intended usage, and benefits of the com- puterized solution are emphasized over theory development and mathematical rigor. Background The mine hoist system that is selected and installed at a mine is the "lifeline" of that mine, with installations lasting 20 years or more. Thorough study is warranted to ensure that productivity demands are met at a minimum cost per ton. The increased cost of a large, powerful, high-speed hoist must be offset by increased production to justify its selection. To optimize this tradeoff, an extensive hoisting analysis should be performed. The analyses to properly size the skip (or cage ) , the drum, and the hoist drive are conducive to computerization, permitting rapid evaluation of changeable operating and design parameters, such as velocity, acceleration, state of balance, and productivity demand. The program is particularly useful in conducting sensitivity trials, such as investigation into the effect of change of productivity on skip capacity and on horsepower of the hoist drive. HOIST is currently limited to the study of drum-type hoists with cylindrical drum(s). However, only minor changes to the program would permit analysis of friction hoists and conical drum configurations. Model development and testing The program is based on accepted equations and physical relationships. Examples of manual calculations formed the basis for decision points and program branching. Data is input in the order that it would be needed if the problems were solved manually. The choices are arranged likewise. HOIST was developed in sections, with manual solutions performed to check program logic. The testing became more rigorous as sections were completed. Output from one section becomes input for following sections, as appropriate. The simplified flow diagram of HOIST is given in Fig. 1.

Jan 1, 1988

By R. E. Ray

As coal reserves at shallow depths continue to be exhausted, a number of US coal companies are developing seams previously considered too deep to mine economically. Because of increased cover load, mines operating in deeper seams face unique ground control problems. In addition, the volume of methane gas in coal beds increases with depth, and ventilation requirements are much more stringent for deep mines than for shallower mines. When the longwall mining method is wed at great depths, ventilation, ground control, and operational considerations all influence the design of longwall panels. This paper examines these influences, particularly ventilation and operational considerations, on the feasibility of two-, three-, and four-entry longwall development panels in Jim Walter Resources' four deep mines.

Jan 1, 1988

By O. J. C. Runnalls

"Canada became the world's largest uranium producer in 1984. That leadership position is likely to be maintained for many years into the future because of a firm production base, many undeveloped known deposits with commercial promise, and a large geologicalpotential for new discoveries.There are some uncertainties on the horizon, principally because of restrictive actions in process within the U.S.A., which are aimed at preserving a deteriorating domestic uranium industry. Should such actions result in import restrictions, for example, there would be a negative effect on foreign producers at least in the short term. Canada may avoid such difficulties under a tentative U.S.-Canada free-trade agreement where restrictions on the import of Canadian uranium into the United States would be eliminated. Over the longer term, demand for Canada's uranium resources will grow because of the foreseen growth in the world's installed nuclear power capacity. IntroductionSince the phenomenon of nuclear fission was discovered in 1938, the utilization of uranium has grown substantially. Initially, the principal use for uranium was in the production of nuclear weapons. However, once civilian nuclear power reactors began to be built in the 1950s, an increasing fraction of uranium output was directed to the production of fuel elements for use in electricity generating stations.The cumulative uranium production by those countries in the World Outside Centrally-Planned-Economies Areas, WOCA, during the period 1938 to 1985 exceeded 800 000 tonnes of uranium. Some 60% of that was mined in the United States and Canada, as indicated in Figure 1. In 1986, nearly 80% of WOCA output came from five countries, Canada, United States, South Africa, Australia, and Namibia, as indicated in Table 1 and illustrated in Figure 2.During the past decade the world annual consumption of nuclear energy has more than tripled (Fig. 3). As of December 31, 1986, the world total of nuclear power reactors had reached 394 with a total net capacity of 270 GWe. The thermal output from nuclear power plants in 1985 exceeded 60% of the energy contained in all of the oil produced that year in the Middle East. Thus, nuclear power has already become an important component in the world energy supply picture."

Jan 1, 1988

By Wilton Johnson

Native asphalt was produced by three companies in two States, Texas and Utah. Bituminous limestone, used primarily as a paving material for street and road repair, was produced by one firm, R. L. White Co., Uvalde County, TX. Gilsonite, a solidified hydrocarbon found only in Colorado and Utah, was mined by two firms, American Gilsonite Co., a division of Chevron Resources Co. (a subsidiary of Standard Oil Co. of California), and Ziegler Chemical and Mineral Corp. Hydrocarbon Mining Co. (a subsidiary of Oberon Oil Inc., a Utah corporation) closed its mining operation during the year.

Jan 1, 1988

By J. M. Krese

This paper gives an overview of the National REAP program emphasizing the program's current status and future plans. A brief historical review of the program will be given containing roof-fall accident trends and statistics. The latest developments in roof control technology and training as it affects the REAP program will be presented. A brief discussion concerning some effects of the implementation of the amendments to Part 75, CFR, concerning roof support is included.

Jan 1, 1988

"INTRODUCTIONThe Kidd Creek Concentrator is located 28 kilometers east of the city of Timmins, Ontario. Two types of ore are treated; 'A' type, a copper-zinc-low silver ore producing copper and zinc concentrates, and 'C' type, a copper-lead-zinc-high silver ore producing copper, lead and zinc concentrates.The ore is processed at a combined rate of 12,400 metric tonnes per day through four parallel grinding and flotation divisions. Three divisions treat the 'A' type ore and the fourth treats the 'C' ore. Each division is fed from its own fine ore bin.This paper reviews the grinding section with specific emphasis on grinding media consumption and the factors affecting it as related to 'A' type ore. At Kidd Creek there was an awareness that grinding media consumption varied on a weekly and monthly basis. The reasons for this variation was usually attributed to ore hardness as evidenced by short term variations in the circuit feedrate and head assays. However, there has been a diversity of opinion published in recent years regarding the factors contributing to steel consumption. This initiated a study of historical Kidd Creek operating data, from the period 1970 to 1986 inclusive, to determine the effect of various operating parameters on media consumption. The results of the study could then be used as a baseline for future media consumption testwork."

Jan 1, 1988

By K. J. Griffin, G. W. Rosval

"In our increasingly competitive market, attempts to improve productivity by increasing axle loads have placed more severe demands on rails. CP Rail thus requires stronger, tougher, and more wear-resistant rails from steel manufacturers. The choice of any rail steel is always a compromise between technical and economic factors. The technical assessment of a candidate rail consists of laboratory and field testing. Laboratory evaluation of rail steels cannot adequately model many service conditions and must, therefore, be supplemented by long-term field testing. The field testing conducted on CP Rail is the subject of this paper.Long-term, in-track, assessment of candidate rail steels begins with the selection and re-laying of a test curve representative of the intended service with both the candidate rail and a control rail steel (i.e. the present intermediate or premium rail standard). The wear performance of the candidate rail is evaluated, in relation to that of the control rail, using data obtained with a rail profilometer developed by the Research and Development Department of CP Rail. Qualitative observations are also periodically made to evaluate the relative susceptibilities of the two rail types to surface defect formation. Testing continues until stable metal loss patterns are achieved. Relative life predictions are then made and detailed monitoring of the test site is discontinued.CP Rail's in-track assessment program for premium rails has resulted in the establishment of a new CP Rail premium rail standard - low-alloy, head-hardened, rails have replaced high alloy rails. The wear/fatigue lives of these new premium rails exceed those of our previous standard by more than 50%, and they also exhibit excellent weldability. CP Rail will continue to evaluate new premium and intermediate strength rail products."

Jan 1, 1988

By Hamid N. Maleki

Cooperative efforts by the Bureau of Mines and Agapito & Associates, Inc., Grand Junction, CO, achieved the research objective of showing that data from measurements of the rate and change in rate of mine roof movement can be effective in detecting roof instability. Several instruments and techniques have been used to monitor roof movement and to detect imminent roof caves during pillar robbing. Early detection of unstable conditions can provide time either to withdraw personnel and equipment or to allocate supplemental support to prevent injury or down-time. Critical convergence rates were determined both manually and electronically. The detection of critical rate of movement has been shown to be an effective tool in ground control efforts.

Jan 1, 1988

By A. D. Trujillo, R. D. Wunder

The Chino Mines Co., a Kennecott- Mitsubishi partnership, located in Hurley, NM, recently completed a $405 million modernization of its mine, concentrator, and smelter facilities. The mine/concentrator modernization commenced in 1980, and the smelter modernization began during 1982. Modernization of the mine and concentrator facilities involved increasing the mining rate from 98 kt/d (108,000 stpd) to 152.2 kt/d (167,800 stpd). Ore mining was designed to increase production from 20.2 kt/d (22,300 stpd) to 34 kt/d (37,500 stpd). A new concentrator was con- structed near the mine using semiautogenous grinding. The new smelter uses the INCO flash smelting process, increasing capacity by 40.8 kt/a (45,000 stpy) to 99.8 kt/a (110,000 stpy) of saleable copper.

Jan 1, 1988

By Gregory M. Molinda

Coalbed discontinuities historically have been hazardous to mining as well as obstructions to efficient production. An effective means of mapping these features is needed in order to plan safe and efficient mine development. This Bureau of Mines report discusses the use of surface seismic techniques for this purpose. At a southwestern Pennsylvania mine, a system of coalbed discontinu-ities (paleochannels) was accurately mapped by the Bureau of Mines using borehole log methods and underground observation. This site was chosen to test the value of a high-resolution surface seismic reflection on technique for coalbed mapping. A statistical study performed at this mine indicated that the probability of accurately delineating this paleochannel system with conventional borehole methods was remote. A total of 1.47 miles of high-resolution seismic survey, comprised of four seismic profiles, was conducted in known and suspected coalbed discontinuity areas. Several test holes were drilled on the seismic lines in order to evaluate the interpretations. It was found, based on these and other existing boreholes, that it is possible to predict these dis-continuities. Paleochannel washouts were correctly predicted in several instances but in other instances were either incorrectly predicted or not predicted in areas of known discontinuities.

Jan 1, 1988

By Bastias J

The Ranger uranium mine has operated in the Kakadu region of the Northern Territory since 1979. The mine's water management system was designed to cater for the wet-dry monsoonal climate and to satisfy the recommendations of the Ranger Uranium Environmental Inquiry - Second Report, 1977 (The Fox Report) with respect to environment protection. The Fox Report advised that the aquatic ecosystem of the region must be protected and that the mine should collect all runoff from disturbed areas. Furthermore, the mine was to operate as a no-release system until release standards, based on the experience of several years of operation and on the results obtained from monitoring and scientific investigations, could be established. Monitoring and research data have now been collected for a decade. it is evident that lower-than-expected concentrations of chemical constituents are present in the runoff waters which are retained on site. Standards have been established for the release of these waters to the streams when in flood during the wet season. Mine water quality data and release standards are presented. It can be confidently concluded that controlled release will not cause detriment to the aquatic ecosystems of the Kakadu region. The Ranger operation has demonstrated that environmentally responsible management of mine waters is feasible for future mining ventures in the Kakadu region.

Jan 1, 1988

By N. C. Saxena

Subsidence investigations in Indian coalfields have led to development of relationships between subsidence movement parameters and defining of safe limits of subsidence movements for surface properties. The maximum subsidence over caved workings was generally not more than 60% of extraction thickness underground while in case of hydraulically sand stowed workings it was generally not more than 5%. The relationships have been useful in extraction of more than 7-million tonne of coal from underneath and in the vicinity of surface properties.

Jan 1, 1988

The Mount Sisa orebody on Misima Island, P.N.G., consists of goldsilver mineralisation associated with massive carbonate and amorphous iron-manganese oxides in fractures and breccia matrix. The orebody forms the northern extension of the Umuna deposit, which lies within a three kilometre strike length of a northwest trending, 300 metres wide, high angle fault zone. The structure is deeply oxidised, with the magniferous oxide material resulting from oxidation of carbonate. The wallrocks are metamorphosed basement psammopelites and basic volcanic rocks, extensively intruded by microgranodiorite. These are dominantly epidotised and sericitised. The precious metals are associated with anomalous Cu, Zn, Pb, Mn, As, Ba, Ga, Sb, and Mo. Many of the features of the Mount Sisa mineralisation are characteristic of volcanic-hosted epithermal deposits of western North America.Lithologic and textural gradation is observed between the carbonate hydrothermal breccia-fill at Mount Sisa, and the quartz dominated brecciafill and dilational fracture-fill mineralisation which forms most of the Umuna deposit to the south. This gradational relationship is analogous to that in the Amethyst-OH vein system at Creede, Colorado, where it is shown to be indicative of deposition from laterally migrating fluids.

Jan 1, 1988

By J. J. Moore, I. Iwasaki, L. A. Lindeke

Correlation of scale-up from small-scale batch laboratory mills to large-diameter industrial mills was established by performing two series of laboratory and pilot plant grinding tests using a magnetic taconite ore and a siliceous sulfide ore. In one series, controlled batch grinding tests in 203-, 508-, and 914-mm (8-, 20-, and 36-in.) diameter mills were carried out followed by a second series involving continuous grinding tests using 305-mm (12-in.) and then 1067-mm (42-in.) diameter pilot plant ball mills in open circuits. The effects of ball diameter on wear and of mill diameter on grinding power and ball wear are illustrated.

Jan 1, 1988

By R. K. Singhal, R. Kolada

A variety of equipment is wed to surface mine oil sands, including bucket wheel excavators/conveyors, draglines, hydraulic shovels, and off-highway trucks. This paper examines the existing mining schemes and equipment wed. Several proposals to improve mine productivity have been presented.

Jan 1, 1988

By D. M. Bodily, R. Jin, W. Hu

Four methods to assess the relative floatability of fine coal have been tested: flotation with frother only, salt flotation, timed-release analysis, and flotation with frother and collector. A practical and simple criterion that combines the separation efficiency (capacity factor) and kinetic rate constant (intensity factor) has been suggested. Five coal Samples from Utah were tested. Based on test results, it was concluded that the floatability test with collector and frother is closer to practice, and according to the suggested floatability criterion, coal fines can be classified into four categories of relative floatability: very easy, easy, moderate, and difficult.

Jan 1, 1988

By W. S. Sadik

This paper presents the ventilation design for an underground testing facility in a salt medium. The underground workings consist of two-12 ft. (3.66 m) diameter watertight shafts and approximately 6000 ft. (1830 m) plus of drifting. These facilities are designed for the purpose of providing access for an in-situ testing of a salt horizon in which a variety of hazardous and non-hazardous materials could be temporarily stored or permanently deposited. The ventilation system includes a design basis for gassy mine conditions and provides for the option of bulk air cooling and heating.

Jan 1, 1988