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By H. Schubert

The flotation of sylvite and also some accessory minerals is performed in brines containing very high electrolyte concentrations. Under these circumstances the mechanims of collector adsorption exhibit some characteristics which will be discussed by significant examples: - flotation separation of sylvite and halite with n-alkylammonium salts and n-alkyl sulfates - flotation separation of kieserite and anhydrite with acylamino carboxylic acids - flotation of halite by collectors which are adsorbed by hydrogen bond formation.

Jan 1, 1988

By Brumley J

The development of the SECV brown coal open cut at Loy Yang will require depressurisation of aquifers both within and below the coal seam sequence in order to maintain open cut stability. Prediction of future open cut dewatering requirements at Loy Yang Open Cut and evaluation of the regional consequences of dewatering has required development of a detailed hydrogeological model of the Loy Yang area. The complex stratigraphy of the coal seam and aquifer/aquitard sequences at Loy Yang have been analysed and integrated with the hydrogeological concepts developed from regional groundwater studies to formulate a realistic hydrogeological model as a basis for finite-element flow modelling.

Jan 1, 1988

By A. J. Neale, B. C. Flintoff

"A review of the dynamic rod mill-ball mill grinding circuit simulator developed at the University of Alberta, highlighting the modular structure and open-ended design, demonstrates the ease with which classical feedback control strategies can be designed and implemented. Various open loop simulations are presented to demonstrate the highly interactive nature of the grinding circuit and to indicate where potential control problems may be encountered. Closed loop simulations are examined, beginning with the basic SISO classical feedback control of circuit product size. Further improvement in the grinding circuit performance in the presence of various disturbances is realized through the application of a classical MIMO feedback controller. As an example of advanced (multivariable) control, static decoupling is implemented and shown to provide additional improvement in overall circuit performance.INTRODUCTIONIt has long been recognized in the processing industries that a dynamic process simulator is an indispensable tool in the design and evaluation of automatic control schemes. In mineral processing the lack of these simulators is felt to have been a major hindrance to the widespread implementation of effective process control systems. In particular dynamic simulation is a necessary precursor to any study of modern (as opposed to classical) process control methods. This paper discusses the development of a dynamic simulator that can be used to study various feedback control strategies. The simulation software provides a powerful educational tool for those individuals interested in grinding circuit control."

Jan 1, 1988

By R. E. Burleigh

'Gold-telluride mineralization was deposited in quartz veins which cut a Late Cretaceous tonalite pluton emplaced near the southern margin of the Peninsular tectono-stratigraphic terrane in south-central Alaska. The gold-bearing veins formed shortly after the development of a widespread Cu-Mo sheeted quartz vein system. Early mineral assemblages consist of quartz, white mica, pyrite, and arsenopyrite (wall rock only). Subsequently, pyrite. sphalerite, chalcopyrite, zoned tetrahedrite and gold precipitated within multiply fractured veins. Late stage galena, tellurides (altaite, nagyagite, coloradoite), and Pb-Sb or Pb-Cu-Bi sulfosalta with gold constitute bonanza ore assemblages that are variably associated with quartz, white mica, ankerite, and calcite. Fluid inclusion evidence coupled with mineral assemblage paragenesis suggests the depletion of volatiles (C02, H2S) and cooling resulted in the precipitation of high grade gold mineral assemblages.

Jan 1, 1988

By R. Callaway

The Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (?CERCLA?), as amended by the Superfund Amendments and Reauthorization Act of 1986 ("SARA?) establishes a comprehensive Federal regulatory program for addressing environmental and public health risks posed by releases of hazardous substances into the environment from a wide variety of industrial and other sources. The statute is primarily administered by the United States Environmental Protection Agency ("EPA"). The applicability of CERCLA to the mining, milling, and smelting industries (hereinafter referred to as the ?mining industry?) has been upheld by the courts and recently affirmed by Congress. The purpose of this article is to briefly outline the scope of CERCLA as it applies to the mining industry, the scope of EPA's activities pertaining to the mining industry under CERCLA, the types of remedies which may be pursued by EPA, and the liability scheme of CERCLA as it applies to corporate entities, managers, and shareholders involved with the mining industry. Natural resource damage claims, State cooperative agreements, and other State-related issues will not be discussed.

Jan 1, 1988

By Bourke J. H, Ashcroft T. B

Many changes have occurred in the world market for manganese over the last five years. Among these, the emergence of divided steel processes for the hot metal refining of pig iron is affecting the use of both ferruginous manganese ore and ferro manganese, at this stage particularly in the Japanese steel industry. Subsequent demand for higher quality manganese materials is promoting the use of thermally beneficiated products such as sinter. In addition, many processes are being developed for the direct smelting of fine manganese ores, of which plasma technology is the most advanced. Cost pressures and product quality requirements are encouraging pre- viously self sufficient countries such as The People's Republic of China and the USSR to import high grade manganese ores to supplement indigenous lower quality supplies. At the same time, Brazil has been provided with the impetus to convert its substantial reserves of ore to value added products.

Jan 1, 1988

By S. J. Page, P. Bolsaitls, W. E. Wallace, C. A. Hill, M. J. Keane

"Boiling respirable quartz dust in water for 10 to 40 minutes decreases the cytotoxicity for both erythrocyte hemolytic potential and pulmonary macrophage release of lactate dehydrogenase in vitro. The potential is reduced to near zero in the boiling concentration range of 1 to 10 mg quartz per ml water in boiling times of 20 to 40 minutes. Below this range the detoxification occurs over a longer boiling time. Above this range the hemolytic potential remaining after 40 minutes of boiling approaches native quartz potential with increasing concentration up to 30 mg quartz per ml water. Replacing the media with fresh at the midpoint of boiling results in full detoxification through 20 mg per ml. Pre—boiling the medium with quartz or silica gel reduces the effect of subsequently boiling test samples. Detoxification persists after mild drying at 110 C for 8 hours, and persists after three days of resuspension in water at room temperature. Additional data on persistence of the effect, on the use of acidic and basic media treatment, and on surface analyses are presented, with a discussion of a working hypothesis and research needs.IntroductionResearch underway to determine interactions of quarts and other mineral dust surfaces with pulmonary fluids and alveolar macrophages in culture led to the observation that when dusts were autoclaved in aqueous suspension, their cytotoxic effects on macrophages wore suppressed, in some cases fully and even after several days incubation with the cells. This finding was in direct contradiction to earlier results from both short term macrophage lysosaal enzyme release assays, as well as longer term cytotoxicity assays from macrophages in culture; in those studies, dusts were steam autoclaved at 121 121 ºC with no liquid water but with steam present. (1,2) However detoxification under boiling conditions has been reported in other research.(3). It was decided to use the hemolysis assay to further investigate these findings, because of its sensitivity, simplicity and cost."

Jan 1, 1988

By Stitt P. H

In Australia, the term "heavy mineral deposits" is used to denote sands which contain variable but economic quantities of the minerals rutile, ilmenite and zircon, often with minor amounts of monazite and xenotime as co-products. Australia has been a significant producer of rutile, ilmenite and zircon from such sands for fifty years and has long been the leading producer of rutile and zircon. The industry had its beginnings with the mining of present day beaches in northern NSW in 1934. Early work was small scale and in some cases involved hand winning of naturally concen- trated mineral for direct export. During World War II and immediately after the industry became increasingly mechanised and by the 1970s on the east coast operated between Newcastle, NSW north to Fraser Island in Queensland. Deposits worked included present day beaches, fossil strand lines up to 5 km or more inland from the present coast and aeolian concentrations. In the mid 1950s, operations commenced on the west coast of WA, south of Perth. Western Australian mineral sands tend to be rich in ilmenite as compared to the east coast. However the WA ilmenites are lower in chrome oxide and make a better syn- thetic rutile feedstock.

Jan 1, 1988

By William H. Schiffbauer

The Bureau of Mines is conducting research that is aimed at making the mining industry more efficient in term of both productivity and the health and safety of the worker. As part of this research the Bureau of Mines has integrated a testbed composed of computer and related peripheral hardware to form an intelligent base for performing autonomous mining machine experiments. Although this particular application was con- figured for use on a Joy 16 CM mining machine, its generic structure facilitates its attachment to a variety of mining machine types. The multitasking multiuser computer can be set up for other applications by changing a bubble memory cartridge. The Joy 16 CM implementation includes 96 digital input-output (1-0) ports, 32 analog inputs, 8 analog outputs, 2 serial data channels, and 1 printer port. Operation of the machine can be performed either through a local terminal or remotely through a modem hookup. This report describes a testbed for autonomous mining machine experiments (TAMME)--its hardware, software, and complete system integration--so that it can be used as a foundation for other applications.

Jan 1, 1988

By R. Hogg

"The problems of sampling particulate materials, and of characterizing the distributions of particle size and composition are reviewed. Requirements for sampling from comminution systems are discussed and a simple formula is presented for estimating the minimum sample size needed. The limitations and errors associated with the techniques available for particle size analysis are evaluated and guidelines are suggested for the selection of appropriate methods. The use of microscopic and macroscopic approaches to the characterization of particle composition are discussed.INTRODUCTIONComminution is a process of particle size reduction in which the goal is to produce a material with a specified particle size distribution from a coarser feed. In mineral processing applications, the product size distribution is often qf secondary importance to the extent to which individual mineral grams can be liberated from one another. However, due to poor understanding of the nature of the liberation process and the lack of reliable procedures for characterizing it, the actual specification is normally in terms of particle size.Particle size distribution can be regarded as the fundamental characteristic of a particulate system. The distributions of particle shape and composition among the various particle sizes present are often sufficient to define the bulk properties and behavior of the system. Description of the distributions of size; shape and composition of the different phases which may exist within individual particles is necessary to complete the picture and is especially important for predicting liberation etc., in comminution processes. It is quite obvious that · the complete characterization of real particulate systems is a formidable, if not .impossible task. Practical characterization procedures should involve ·evaluation of those characteristics which are deemed to be important and which can be measured. In comminution systems, this should ideally include the particle size distribution, the size-by-size distributions of particle composition, and as much information as can be acquired on the internal composition and structure of individual particles. In most cases, of course, we fall far short of even this rather limited goal."

Jan 1, 1988

By Buizen M, Eagleton A. C

The results of calibration trials conducted on parachute stoppings both overseas and in Australia under a recently completed NERD&DC grant, are presented. Applications of parachute stoppings, for rapid regulation and control of ventilation networks are described including use in blasting areas and rescue work. Several parachute-type stoppings are described and their applications Investigated

Jan 1, 1988

By Vidalinc, Raffoux

Longwall faces producing in the order of 20,000 tons per day of raw coal are presently running in the Houilleres du Bassin de Lorraine of Charbonnages de France. Production levels of twice that level pose some technical and economic problems of coal cutting, ventilation, coal and equipment transportation in the.face and from the face to the sur- face. The peak productions of the equipment in use today, the results of trials with new equipment, the utili- sation of forecasting models (some in the form of software), allow us to fo- resee feasable technical solutions to these problems. They will first be considered in the best possible context (thick- ness, dip, non gassy, soft coal, good strata, no faults). This will give. the necessary conditions to reach daily output'of that level. A sensitivity analysis of these- figures to the effective natural con- ditions will then be undertaken and the implication of such a project on health and safety (dust, climate ...) will be carefully considered. A concise technical and econo- mical approach will permit us to fore- cast the economical interferences of such production units and specially the consequences of sudden variations of the output (downtimes, failures, etc). From this investigation, goals for technological development and re- search areas will be outlined to be able to reach this production target in the XXIst century.

Jan 1, 1988

By Z. Yang, R. W. Smith, Jr. Wharton

"Microorganisms have the ability to remarkably adsorb and/or absorb heavy metal ions. Hence they are being studied widely as a means of removing metal ions from aqueous solutions both in order to clean up toxic streams and to recover valuable metals from these and other streams. It is often difficult to harvest organisms such as bacteria and unicellular algae since they are usually too small to be readily screened out. Froth flotation may prove to be a feasible method to harvest such organisms subsequent to the ad/absortion of the metal Ions. The present paper discusses the surface/electrokinetic properties of microorganisms and the modifier-collect conditions under which they should float. The zeta potential of the green alga Chlorella vulgaris was measured in the presence of AI(III) and Pb(II) ions and in the presence of dodecylammonium chloride and sodium dodecylsulfate. Present and past data suggest that the organisms should behave similarly to other finely divided, charged (polar) solids with their behavior sometimes modified by the non-polar surface regions present.IntroductionThe overall field of bioengineering is growing at a remarkably accelerating rate. Hydrometallurgy and mineral processing are included among those disciplines where there has been actual or proposed commercial use of bioorganisms. Further, the actual or proposed use includes bacterial enhancement of leaching of a number of different types of ores (1-5), modification of the flotation or oil agglomeration separation of minerals by bacteria (6,7) and microorganism (algae, bacteria or fungi) concentration of metal ions present in effluent or other mineral processing or hydrometallurgy aqueous streams (8-23)."

Jan 1, 1988

By J. A. Ryder

A high proportion of damaging rockbursts are thought to be underlain by seismic events that represent shear or rupture along planes of weakness (faults, joints, dyke contacts). Such events are controlled by shear stresses and friction properties along the plane. Excess shear stress (ESS) is a measure that can be evaluated numerically and that, in principle, can be used in an assessment of the possible magnitude and relative likelihood of seismic activity. Methods for the calculation of ESS in practical mining contexts, and for the estimation of the magnitudes of possible seismic event progressions, are briefly reviewed. The effects of variables such as depth, stoping width and, in particular, virgin horizontal stresses on general shear-type seismic hazards are investigated. Attempted back-analyses of two large rockbursts are described.

Jan 1, 1988

The Bureau of Mines, in an effort to improve resource conservation, mine planning and development, is currently investigating the loading behavior of pillars in multiple-seam developments. The simultaneous mining of two or more coalbeds may cause instability between room-and-pillar operations resulting in an interaction known as pillar load transfer. Although pillars may be adequately designed for single-seam mining, the development of a second seam may complicate loading conditions in both operations. If pillars are not adequately designed to contend with this load transfer, failure of the mine structure may result. To improve multiple-seam development and pillar design, the Bureau studied the loading characteristics of pillars in three separate multiple-seam operations. In all three cases, instrumented pillars recorded increasing pressure after development of the second seam. Increases in the average pillar pressure ranged from 7 to 110 pct over predicted overburden loads. An analysis of pillar loading before and after second-seam mining indicates that the ratio of overburden to innerburden thickness is a critical factor influencing load transfer. Based on this relationship, safety factors for case study pillars are calculated and alternative design considerations are discussed.

Jan 1, 1988

Krupp Polysius AG, FRG, in close cooperation with Prof. Dr. K. Schoenert, FRG have developed the principle of the high pressure grind- ing roll POLYCOM. The POLYCOM mill basically consists of two counter-rotating rolls of large diameter and relatively small width, one of which is fixed and the other moving in slide blocks. The pressure required for comminu- tion is applied via the sliding roll by a powerful hydraulic system. The comminution takes place between the rolls under high pressure in the bed of material by nipping and compacting. The top feed size-depending on the rolls diameter -may be as coarse as conventional secondary crusher feed and the product is a compacted cake containing a high amount of fines created by micro-cracking. The amount of fines depends on the pres- sure (grinding force) applied. Operating results show that even in wet griding circuits capacity increases at downstream connected grinding mills of up to 100010 can be accomplished with an interconnected POLYCOM machine and energy savings of up to 25070 may be achieved depending on application. POLYCOM can be used in existing grinding plants for low-cost upgrad- ing of capacities but also as an advanced alternative to conventional crush- ing and grinding equipment in open or closed circuit configuration. A single industrial size 2.8m roll diameter POLYCOM machine may be fed with top feed size of up to 200mm and produce a finish product as fine- grained as known from rod and ball mills but with less energy consumption. Meanwhile, the POLYCOM high pressure grinding roll has established itself world-wide in the cement industry and is now entering the mining industry. POLYCOM machines are currently designed in industrial standard sizes of 1.0m to 2.0m rolls diameter and drive units of up to 2400 kW. This paper includes: principles of high pressure grinding, main fea tures of the POLYCOM machine, results of tests on various materials including Australian gold and copper ores carried out at the POLYSIUS research centre in Germany. Some examples of industrial applications of high pressure grinding will also be presented.

Jan 1, 1988

Pictured on these pages are the seven RMCMI Scholarship Award Winners for the 1987-88 year followed by a brief profile. Six of the winners were present as RMCMI guests at the June convention in Breckenridge, Colorado to receive their recognition plaques at the welcome session held Monday, June 27, 1988. In addition to the plaques, each winner receives $500.00 to be used toward tuition in the coming academic year. Also, as this is a continuing award, the winners from the previous year will also receive an additional $500.00 for tuition use in their senior years provided they have maintained a good academic standing and are recommended by their university. Criteria for these awards is (1) That the award be made in the spring to a sophomore student to be used toward tuition during the junior year. (2) That the recipient be both a U.S. citizen and a resident of the state involved. (3) That the recipient have good academic standing, be pursuing a degree in a mining related field and have an expressed interest in Western coal as a possible career path. The scholarship program was extended in early 1988 to include curricula other than mining department, but in the engineering disciplines, such as geology, mineral processing and metallurgy. Contributions to this worthy project are tax deductible to each individual RMCMI member. Checks payable to RMCMI Scholarship may be mailed to the RMCMI Office at 2700 Youngfield Street, Suite 100 in Lakewood, CO 80215. Profiles of the 1988 winners follow: [ ] Anthony T. Bowler University of Arizona Tucson, Arizona Tony has taken a well balanced curriculum and at the same time maintained significant progress toward a Geological Engineering degree. He is interested in computer science and programs as a hobby He is the master of several computer languages including machine language on different personal computers. [ ] Christopher Taylor Colorado School of Mines Golden, Colorado Before matriculating at Mines, Chris served four years with the U.S. Army Special Forces attaining the rank of sergeant. He is active in the military, serving in the Reserves and R.O.T.C. This duty precluded his attendance at the Breckenridge meeting. He plans to get summer work experience in mining before graduation and is interested in the managerial and technical aspects of the mining business. [ ] Laverne West New Mexico Institute of Mining & Technology Socorro, New Mexico A native American of Laguna/Navajo ethnic origin, Laverne graduated from the Sante Fe Indian School as valedictorian. She served as both secretary and president of the American Indian Science & Engineering Society. She works at the Nevada Test Site with contractors assisting project engineers in a variety of jobs. She plans to earn a dual degree in Mining and Geological Engineering then pursue a Master's degree in Mineral Economics at the University of California at Berkeley. Among her honors are a four year scholarship from Sante Fe Southern Pacific Foundation, a one year scholarship from Mobil Oil Corporation and another from Eastman Kodak.

Jan 1, 1988

By A. Wahab Khair

This paper presents an analysis of surface ground movements recorded from two longwall mines in Northern West Virginia which operate in the Pittsburgh Seam. The instrumentation areas consisted of four panels, two at each mine, covering various sections with unique topographic features. Instrumentation consisted of survey monuments on 25 to 120 ft. spacing. Vertical and horizontal ground movements were measured at specified intervals to determine subsidence rate, developing and final subsidence profiles, angle of draw, horizontal displacements and associated strain profiles. A relationship between panel depth and width and the subsidence factor was also developed.

Jan 1, 1988

By D. J. Briggs

The use of backfill for regional and local support is receiving increasing attention in the South African mining industry. To ensure that fill materials meet the purposes for which they are intended, a test procedure to characterize the load-deformation characteristics for a particular fill was developed. The major variables identified as influencing the load-bearing proper- ties of backfill include particle size distribution, porosity, width-to-height ratio, strain rate, confinement, water content, and additives. The influence of these variables on the performance of backfill is described in relation to crushed waste, dewatered tailings and deslimed tailings. These investigations confirmed that no single test could be used to define the overall stress-strain behaviour of a selected fill. Nevertheless, resulting from this work, a preliminary standard test procedure for uncemented backfill materials, com- prising a suite of tests in unconfined and confined compression, has been formulated. This test procedure is a significant advance towards a more meaningful evaluation of fill materials. Test results will also provide numerical information for input use in computer programs for the design of mine layouts incorporating backfill.

Jan 1, 1988

By W. F. Moore

"In January 1981, Quintette Coal Limited (QCL) signed a 2a-year coking coal sales agreement with the Japanese Steel Industry which was followed by the commencement of mining operations in October 1982 and preparation plant operation in November 1983. During the mine 's startup, the town of Tumbler Ridge, the Anzac rail spur line, coal port facilities at Ridley Island plus numerous related elements of infrastructure were completed to support QCL and the neighbouring Bullmose operation in northeastern British Columbia. QCL's annual product coking coal levels have accelerated from 2.9 to 5.2 Mt between 1984 and 1986 with related increases in total mined volume from 14.8 to 41.0 M BCM between 1983 and 1986. This paper presents an overview of QCL 's current operation and related infrastructure. Development BackgroundDuring the 1970s, the Japanese Steel Industry (JSI) was forecasting a steady and significant growth in its steel production. By 1980 they were expecting crude steel production to increase from about 105 Mt in 1980 to 125 Mt by 1985 and almost 140 Mt by 1990.Discussions between Quintette Coal Limited (QCL) and the JSI for the development of the QCL project began in the 1970s and continued over a period of several years. During that time detailed and regular meetings took place, at which technical and commercial presentations were made to the JSI. The geology of the project area and the alternative mining methods and sequences were studied in detail. The new rail line which would connect the mine to tidewater was a critical factor and received particular attention. Alternate routes for the rail line from Tumbler Ridge to Prince George were the subject of much detailed study and discussions. The Anzac route was chosen in the best long-term interest of the northeast area development, after careful consideration and advice from the Japanese side.The new bulk coal terminal on Ridley Island at Prince Rupert was also a key factor and completed the development of an independent and new major coal field to supply the JSI. The QCL project and the development of the northeast area of British Columbia was a major strategical initiative of the JSI. It provided Japan with an important new coal field which was both self-sufficient and distinct from the traditional Japanese coal field resources in southern Canada, Australia, and the United States."

Jan 1, 1988