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By R Byrnes, P Hensley

The outstanding environmental management initiatives undertaken by Novacoal at its Western Main Site near Lithgow in New South Wales over the past five years are detailed in this paper. These initiatives have been based on a combination of proven and innovative investigation and implementation techniques, close consultation with regulatory authorities and full support by colliery management. The results of these initiatives have enabled the colliery to exceed its pollution control obligations from a base well below industry standards. The initial poor condition of the mine was the result of over 50 years of traditional mining which paid little regard to environmental management. The transformation of the colliery within such a short period, with limited capital, is considered a model for the N.S.W. coal industry.

Jan 1, 1995

By P. T. Velu

Light weight aluminum alloys are the major construction materials for a number of structures in automobile and aerospace industries. Higher cost of production is the key impediment which restricts the usage of these alloys. A new electrochemical process route for the low cost production of aluminum alloys is being investigated, in which alloying elements are obtained from the dissolved compound. In the present investigation, solubility of lithium compound has been determined by measuring the EMF, when it is dissolved in the electrolyte. The solubility of Li2CO3 increased with temperature from 2.95 wt pct at 1063 K to 7.57 wt pct at 1093 K. Activities of the compound in the electrolyte were deduced using Temkin's ideal solution approach.

Jan 1, 1995

By Thomas J. Peters

At the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines and U.S. Geological Survey conducted a mineral investigation of about 85,470 acres of the Diablo Mountain Wilderness Study Area, to determine mineral resources and mineral resource potential. The study area is in Lake County Oregon, about 45 miles northwest of Lakeview. Fieldwork was conducted in 1986, 1988, and 1989. Geologically, the study area lies on the northwest edge of the Basin and Range physiographic province, a region of fault block-formed mountains and basins characterized by interior drainage. Consolidated rocks are mostly Tertiary basalt and tuffaceous sedimentary rocks. Low-lying areas are covered by Quaternary alluvial-fan, sand-dune, playa, lacustrine, and landslide deposits. The principal structural features are normal faults that have large vertical offsets; these faults are typically concentrated at the margins of large horst and graben. The 34,310-acre "additional," or western part of the area was mainly studied in 1988 and borders the east shore of saline Summer Lake. In this portion of the study area there is potential for undiscovered resources of soda ash, boron compounds, and sodium sulfate as well as by-products, which include magnesium compounds, salts, potash, bromine, lithium, and tungsten associated with brines. No energy or mineral resources were identified in the study area, but brines within lake and playa sediments contain concentrations of chemical components suitable for the production of soda ash, boron compounds, and sodium sulfate. Possible by-products include potash, salts, bromine, lithium, magnesium compounds, and tungsten. Limestone from the study area could be used in the recovery process of brine components or agricultural uses. The study area includes thermal springs and lies within 2 miles of the Summer Lake Known Geothermal Resource Area. Local production of geothermal power by the binary process may be economically feasible. Soda ash, soda ash products, and boric acid are widely used in fluxing metals, and have important applications and markets in the aluminum industry in the northwest and the developing Chinese counterpart. Evaporite commodities are essential to many "backbone" industries, and to many new applications and advanced materials. Markets for brine mineral products appear to be undergoing steady and strong growth, especially in the Pacific Northwest and in Pacific Rim countries. Soda ash produced near the study area would be 55 percent closer by rail to marine export at Portland, Oregon, than trona deposits of the Green River District (Wyoming). Soda ash and a daughter product, caustic soda, and sodium borohydride will receive increased application in the bleaching of paper pulp for environmental reasons. Caustic soda, used in many industrial processes, is more environmentally friendly when derived from soda ash than when produced from sodium chloride salt, because of the absence of a chlorine by-product. Producing soda ash from brines, a type of in situ" mining, can be done with minimal environmental degradation, and mining natural soda ash is environmentally as well as economically preferable to synthetic soda ash production.

Jan 1, 1995

By P. E. Fox, R. S. Cameron

"The QR gold deposit lies in the Cariboo plateau region of central British Columbia. The deposit was discovered in 1977 and since then a mineable reserve of 1.3 million tonnes grading 4.7 g/t Au has' been outlined in three separate zones. Soil sampling of glacial tills followed by diamond drilling of favourable host rocks proved to be key exploration techniques.The deposit is situated in the southern Quesnel terrane along the eastern fringe of the Intermontane Belt which here comprises a sequence of basic and intermediate volcanics and a series of stocks of alkaline affinity; generally diorite, monzonite and syenite. Hornfels and epidote-rich ferromagnesian exoskarn and sulphide-rich mantos have developed in a metamorphic aureole formed around a central diorite stock. Gold-rich zones lie along the outer periphery of the aureole where bodies of gold-bearing epidote-rich skarn and auriferous mantos rich in epidote and pyrite have formed in beds of calcareous tuffite lying at the top of a thick basaltic sequence. The deposit is regarded as' a subclass of gold skarn deposits. Diagnostic features are its association with alkalic intrusive rocks in a subvolcanic setting and the presence of oxidized, epidote-rich mineral assemblages.IntroductionThe QR gold deposit lies within the Cariboo plateau region of central British Columbia, 58 km southeast of Quesnel. The deposit, owned by Kinross Gold, was discovered during a regional reconnaissance program by Dome Exploration (Canada) Limited and Newconex Canadian Exploration in 1977. Considerable exploration and development has been done since that time. Mineable reserves of 1.3 million tonnes grading 4.7 g/t Au have been outlined to date in three zones."

Jan 1, 1995

By B. J. Arnold

With the passing of the 1990 Clean Air Act Amendments, many utilities are opting to switch to lower sulfur coal to meet new SO2 emissions requirements. This lower sulfur coal may be from new suppliers or it may be from current suppliers that modify existing cleaning plants or build new plants to produce this higher quality coal. New, sophisticated coal cleaning simulators are useful tools for optimizing cod cleaning circuit operating parameters to maximize the production of clean coal that meets more stringent specifications for SO2 emissions potential. The examples in this paper were developed using the Coal Cleaning Simulator (CCS), running under ASPEN PLUS™, that was developed under a Department of Energy project cosponsored by the Electric Power Research Institute. With advanced sensitivity analysis and optimization features, CCS allows a quick, efficient, cost-effective review of coal cleaning plant performance to meet current production goals and to plan future changes in plant operating parameters or circuitry configurations.

Jan 1, 1995

By Guvenir HA

This paper summarises a cost optimisation procedure by minimising the total drill metres and the overbreak that occurs in tunnel excavation in medium strength rock (uniaxial compressive strength

Jan 1, 1995

The reformulation of military explosives and solid propellants into commercial explosives offers a unique solution to the problem of disposing of high energy materials with essentially zero environmental impact at a low cost and with a salable product. Studies using the insensitive PBX PBXN-4 have been completed through the pilot plant stage and have been successfully tested as a mining explosive. A number of other military explosives have been examined and their VODs and heats of explosions determined and in some instances tested in 'field" operations.

Jan 1, 1995

By Fernando A. Concha

There is confusion in naming the several models developed in Mineral Processing. We often hear of empirical, first principle, mechanistic and phenomenological models. The objective of this paper is to clarify and distinguish between these models, based on a philosophical and linguistic analysis. A state of the art review for mathematical modeling in Mineral Processing is also made.

Jan 1, 1995

By Hubert den Dikken

ache, especially when it comes to forwarding of small quantities. Air transport is limited to 1.4 explosives on cargo aircraft and 1.4S classified explosives on passenger aircraft, so most samples cannot be transported by air. Ocean transport is a possibility, but due to stowage and segregation regulations of the IMDG code, a very expensive one. Road transport is often the only solution, but high explosives require special trucks with licensed drivers. The solution to these logistic problems is solved by creating a 1.4S (Class C) classification for all high explosives, when packed in special containment vessels.

Jan 1, 1995

By D. N. Cleaver

Like other influence function methods, the SWIFT subsidence prediction program, developed within the Mineral Resources Engineering Department at the University of Nottingham, requires calibration to regional data in order to produce accurate predictions of ground movements. Previously, this software had been solely calibrated to give results consistent with the Subsidence Engineer's Handbook (NCB, 1975). This approach was satisfactory for the majority of cases based in the United Kingdom, upon which the calibration was based. However, in certain circumstances within the UK and, almost always, in overseas case studies, the predictions did not correspond to observed patterns of ground movement. Therefore, in order that SWIFT, and other subsidence prediction packages, can be considered more universal, an improved and adaptable method of regional calibration must be incorporated. This paper describes the analysis of a large database of case histories from the UK industry and international publications. Observed maximum subsidence, mining geometry and Geological Index for several hundred cases have been statistically analysed in terms of developing prediction models. The models developed can more accurately predict maximum subsidence than previously used systems but also, are capable of indicating the likely range of prediction error to a certain degree of probability. Finally, the paper illustrates how this statistical approach can be incorporated as a calibration system for the influence function program, SWIFT.

Jan 1, 1995

By M. I. Dobrynina

At the beginning of the 80-s the first diamond pipe in the East-European platform was discovered in the North of the Russian Federation on the White Sea Winter coast. During several years while studying this unique area data on kimberlites and country rocks petrophysical characteristics have been collected. Considerable experience in geophysical methods when searching and exploring diamonds was accumulated, and various methods of geophysical data interpretation were used. It has been established from the analysis of geophysical data that diamond-bearing kimberlites are located in the most ancient and the most stable block of the East-European craton.

Jan 1, 1995

By D. J. Turk

Faced with decreasing production from the gold heap leach operation, Robinson implemented a drilling and blasting program on the leach pads in 1993. This program offset some of the negative effects of low ore permeability and short circuiting of leach solution that resulted in lower than optimum recoveries. The drilling and blasting program created new solution flow paths and increased gold recovery. Production and pulp assays at depth intervals, prior to and following drilling and blasting, reveal the degree of short circuiting and benefits of the program.

Jan 1, 1995

By George K. Mitteer

The Cowles Mountain Tunnel was driven 2,073 m (6,800 ft) with a 3.43 m (11 ft 3 in) shuffle shoe TBM, for the San Diego County Water Authority, through extremely high strength granitic rock in the City of San Diego, Ca. The initial contract was $10.9 million. Tunneling began in March 1992 and all work was completed in May 1993. After the tunnel drive was completed in September 1992, a 2.44 m (96 in) Welded Steel Pipe was installed, welded and encased with cellular backfill to complete a small portion of the County's $970 million Capital Improvement Project. This paper will discuss the successful completion of a tunnel through some of the hardest most abrasive rock ever excavated with a TBM in North America.

Jan 1, 1995

By S. F. Smith

Following a roof beam collapse on a major production district at the British Steel Corporation's Dragonby Iron Ore Mine, Scunthorpe, South Humberside, UK, rock mechanics investigations were undertaken in this room and pillar operation to assess the stability of workings throughout all the underground mine area. Over a four year period room convergence and roof sag were monitored in different mining areas and various junction configurations in order to assess and compare the relative movement of the strata resulting from mining activities, where varying rock bolt lengths and patterns have been utilised. The paper, after shortly describing geological aspects and mining methods, presents the research procedure adopted together with the instrumentation employed and discusses the results obtained during these investigations.

Jan 1, 1995

By Fleming GJ

The Miwah prospect lies on the dilational 070¦ trending Miwah Lineament near its intersection with northerly oriented fractures within Pliocene volcanic rocks exposed between a NW trending segment of the dextral transcurrent Sumatra Fault, and the more northerly trending Samalanga-Sipopok Fault to the east. These faults reflect the continued interaction between stresses from the India-Australia plate located to the southwest, and spreading within the Andaman Sea to the north of Sumatra. A system of deep seated faults is believed to have facilitated emplacement of post-Miocene magmas and Quaternary volcanic centres at shallow crustal levels throughout northern Sumatra.

Jan 1, 1995

By Sudhir C. Dhara

An attempt has been made on the concentration of Platinum Group Metals (PGM) from the converter matte material by microbial .leaching. Biological oxidation of base metal sulfides such as iron, copper, nickel and free sulfur present in the matte material using Thiobacillus ferrooxidans is an alternative method to concentrate the PGM-and gold. The method which produces a platinum group metals concentrate is comparable to chemical processes and electrochemical process.

Jan 1, 1995

By D. G. Hulbert, J. H. Schubert, R. G. D. Henning

"Froth depth, along with reagent addition and aeration rate, is one of the crucial factors that can be used to control a flotation circuit. Sub-optimal setpoints and disruptions in levels have a severe adverse influence on grades and recoveries. A novel control strategy has been developed which provides exceptionally tight regulation of pulp levels. The controller observes and acts on all the flotation levels simultaneously. This provides a clear improvement over the standard approach, which is to use a set of Pl controllers. The system has been run on several industrial plants and has resulted in reduced fluctuations in level; fast responses to setpoint changes, and fast settling times after start-ups or disturbances. Testwork has shown that the improvements in level stabilisation translate into improvements in recovery and grades.IntroductionProcess control and optimization have an important influence on the economic efficiency of flotation plants. Inefficient operation can allow the wrong balance between grades and recoveries, and can also lead to adverse shifts in the grade-recovery relationship. Of all metallurgical operations, flotation loses the largest proportion of valuable material. Better operation can reduce these losses.An essential requirement of a good controller is that it should be able to stabilize and regulate the plant. Stable operation allows the performance of the plant to be observed without being obscured by the effects of disturbances and fluctuations. The optimum conditions can then be detected more easily. Good regulation can maintain operation at the optimum with proper neutralization of disturbances. Only when good stabilization and regulation are achieved can an optimizing strategy be properly applied.Froth depth, aeration rate and reagent addition are the three means by which a flotation plant is generally controlled. These control actions are effective on different time scales. Reagent addition is slower in its effect as some conditioning time is required. Since reagents are only added at the head of the circuit and at a few selected points within the banks, time is required for the effect of reagent changes to move through the circuit. Because of this slower time constant, reagent addition is more suited to process optimization and to dealing with slower changes in the process. An example of these slower changes is variation in the feed."

Jan 1, 1995

By Bruce Vandenberg, Andy Bartfay-Szabo, Steve Conway

Recent advances in solid-state, field portable, fast framing video camera systems and PC based frame capture hardware now allow blast imaging up to 500 frames per second. Up to 8 seconds of data can be stored directly into the unit, downloaded to a PC or archived to a standard VCR without data compression. Since no film processing is involved, motion analysis can be performed instantly and on-site within a few minutes. This paper will describe the design features and applications of the SVClOOO system and compare these with the analogous aspects of film based cameras.

Jan 1, 1995

By J. W. Cash

The mineralogy and textures of cyclone dust, sludge, and occasional build-ups in the American Iron and Steel Institute (AISI) direct iron making pilot plant at Universal, Pennsylvania have been studied by reflected light, transmitted light, and cathodoluminescence microscopy, and phase compositions have been determined by SEM-EDS. The cyclone dust consists of particles of carbon, metallic iron, sulfur-bearing iron, and wustite. Measurements of particles in the sludge indicate that 69% are less than 2.5 µm across, 21 % are 2.5-5 µm, and 10% are larger than 5 µm. Mineralogically the sludge particles are mainly carbon and metallic iron, with minor wustite and sulfur-bearing iron. Build-ups that sporadically develop in the furnace consist of olivine, hercynite spinel, metallic iron, wustite, pyrrhotite, pseudobrookite, akermanite-ferroakermanite and gehlenite. The microtextures shown by the build-ups indicate that much of that material has precipitated at the build-up loci. This study has been supported by AISI and the U.S. Department of Energy.

Jan 1, 1995

By Vynne J. F

Drill monitors for rotary blasthole drills have been available to the mining industry since the 1970s. The early monitors were pen strip chart recorders that were developed for the oil drilling industry and adapted to mining. They recorded drilling parameters such as depth, pull-down pressure, torque, RPM, and hailing air pressure. While these recorders could generate a large volume of paper, the amount of useful data was minimal. The data was not summarised and required an engineer to interpret the chart traces. Being a mechanical recorder, the devices were also susceptible to frequent failures. Modem electronics, and the development of the personal computer and its associated software have radically changed the type of instrumentation that is now available for blasthole drills. Perhaps more important is what can be done with the data. The PC allows the logged data to be analysed, summarised, and a variety of reports to be generated. The reports can be customised to meet the specific requirements of the mine and reduce the amount of time that is required to interpret the data. There is also an increased awareness in the mining industry of the importance of production drills. Blasthole drills have typically been the piece of production equipment that received the least amount of attention in a surface mine. Management focussed on the trucks and shovels or draglines. This situation is changing, and therefore the benefits that can be derived from monitoring drill performance are being recognised. Potential economic benefits of installing drill monitors have been documented in previous papers (Peck and Vynne, 1992). Mines are finding that pay-back periods of less than twelve months and rates of return in excess of 30 per cent are not uncommon. These benefits include the following: 1. Reduced overdrilling; 2. Increased rate of penetration; 3. Helping to locate coal seams; 4. Identification of weak and strong zones; 5. Reduce geophysical logging; 6. Optimising blasts; 7. Improved fragmentation and diggability; 8. Decreased coal dilution; 9. Increased bit life; 10. Reduced maintenance costs; 1 I . Improved accuracy of data and reports.

Jan 1, 1995