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By G. Johnston, P. K. Chatterjee, S. Holguin

Underground mine planning is largely manual and can demand considerable resources to generate a working plan and to perform limited tests of sensitivity to variations in geological and mining conditions. It is possible to use computer aided mine planning to automate many of the manual procedures to allow the planner to evaluate a number of layouts, extraction strategies, and schedules. his paper examines the simulation and scheduling of an under- ground coal mine operation through the-use of on- screen graphics. The simulation will provide a basis for predicting productivity and other relevant information over a specified number of shifts. The software developed is extremely user friendly and reduces the tedium of repetitive manual calculations inherent to mine planning and drafting to a minimum, thus offering considerable savings in an area that is widely recognized as extremely labor intensive.

Jan 1, 1988

By Noel N. Moebs, John L. Ellenberger

Geologic structures in mine roof rock contribute to many roof falls in Appalachian coal mines. These structures include paleochannels, scours, pinch-outs, slickensides, clay veins, and cravasse splays consisting of thinly interlaminated sandstone and shale. These structures often can be identified during, and sometimes before, development and mine projections can be revised to reduce the adverse effects of discontinuities in roof structure. Large areas of roof consisting of laminated sandstones or incompetent strata generally can be delineated from exploratory drill-hole data and the need for supplementary support can be anticipated. Because an accurate description of roof geology also provides some indication of optimum length and type of roof bolts that should be installed, this Bureau of Mines paper describes the hazardous roof structures most commonly encountered in the Appalachian coal region.

Jan 1, 1982

By Justus B. Deen

Given that the majority of mine ventilation operating costs are imposed by shafts, the need to predict the resistance of a planned shaft with reasonable accuracy is important. During conceptual design, shaft resistances are usually predicted by use of published friction factors, k, based upon lining and fitting configurations. More often than not, published friction factors do not directly coincide with "real" shafts, so their use is somewhat limited. For more accurate shaft resistance determination, equations both theoretical and empirical may be employed if there is detailed knowledge of the shaft. These equations treat the shaft resistance as discrete components, with their sum being the overall shaft resistance. This paper describes the basic shaft resistance equations and verifies these equations by comparison to field measured shaft resistances. Several shafts were examined which varied in depth, shape and fitting arrangements. Results are presented and conclusions drawn to show that the shaft resistance equations are accurate.

Jan 1, 1991

By B. C. Cornilsen, X. Shan, D. H. Carlson, J. H. Johnson

Airborne respirable Diesel Particulate (DP) presents an additional health hazard in that it has been shown to be mutagenic. This problem is of increasing concern as more coal mines introduce diesel vehicles. If the DP present in coal mine air is to be controlled it must first be measured. This paper describes development of the laser Raman spectroscopic measurement of the amount of DP in DP/coal mixtures collected on filters in the laboratory and in coal mines. The Raman technique provides a chemical measure of the carbonaceous material in each component, and is not dependent upon particle size. When this work was begun there were no known analytical methods for this measurement. Side-by-side in-mine comparisons of the results obtained from Raman, neutron activation analysis, and size selective analyses (MOUDI and personal samplers) are presented. The neutron activation and size selective analyses were obtained by the USBM Twin Cities Research Center and University of Minnesota. Good agreement has been found among these three methods.

Jan 1, 1991

By Jack E. Thompson

Thank you Tom and JM for that nice introduction. The remarks I am about to make rely on a large way on comments made by Barrick's Chief Counsel, Patrick Garver, to an internal meeting of Barrick's senior staff. I plagiarized so much from his notes that I thought that I should provide attribution. I did get his consent to borrow so freely. What I have done is take his general comments and used my conversations with CEO's and other participants in the industry to enhance the message with concrete examples that underscore the points I wish to make. What you are about to hear is my personal view – I am not speaking as a representative of any company. With that introduction, now would be a good time to give you the main theme of my talk: The SEC should change its rule making to a more public cooperative approach. If that were to happen the SEC would avoid some of the harm it has been doing to the companies in this sector and the very shareholders it seeks to protect.

Jan 1, 2003

By E. T. Balazs

Share of developing countries in world bauxite resources mining and processing. Technical assistance of the United Nations Industrial Development Organization to the developing world in the field of bauxite evaluation and processing. Review of selected projects of bauxite research and development aimed at creating indigenous capabilities in developing countries: "Assistance to the bauxite aluminium industry of the People's Republic of China". Project activities. UN inputs. Achievements. Follow-up. "Upgrading the scientific and technological capabilities of the Jamaica Bauxite Institute". Project activities. UN inputs. Achievements. Expected follow-up. Assistance to the establishment of an "Aluminium research, development and design centre" in India. Project activities. UN inputs. Achievements. Follow-up. "Establishment of an aluminium institute for research and development in Titograd, Yugoslavia". Project activities. UN inputs. Achievements expected. Second UNIDO group training on bauxite evaluation and processing to alumina October - November 1983 in Budapest, Hungary. Programme and coverage. Show of movie picture on organization and execution (15 minutes). Significance of UNIDO's assistance to the developing world in bauxite research and development. References.

Jan 1, 1984

By G. P. Dvoichenkova, E. A. Trofimova, M. V. Zaskevich, V. A. Chanturiya

The paper presents theoretical and practical aspects of directed adjustment of physicochemical properties (pH,Eh) and ion composition of recycle and mine water by electrochemical treatment. Treatment is run in the conditioners of diaphragm-type with production of alkaline catholyte of pH value up to 12 and acidic anolyte of pH up to 2. In process of water electrolysis the directed motion of Mg2+ and Ca2+ ions is observed from anode volume to cathode one, were they precipitate as hydroxides and carbonates; it leads to decrease of salt content in anolyte and catholyte. The anolyte has been concentrating anions, it is being saturated with oxygen, which reaches 20-35 mg/L. The results of experimental and industrial testing of electrochemical technique for mine and recycle water in flotation of diamond-containing and sulphide-scheelite, hematite, phosporite, apatite-nephelite, bauxite ores indicated the increase of recovery up to 2-1 5% and grade up to 0,5-2%, concurrent with decrease of reagent consumption from 15 to 50 %. Modules of industrial conditioners of different type capacity have been developed.

Jan 1, 1995

By Charles Dr. Li, John Dr. Box

Selective flotation and adsorption behavior of zircon and rutile under hot soap conditions have been examined. Conditioning temperature, pH and washing steps were shown to control the flotation selectivity. The adsorption of the sodium soap of oleic acid at zircon- water and rutile-water interfaces was investigated through micro- electrophoresis and adsorption density measurements. The soap adsorption on the zircon surface increased markedly with increasing temperature due to a strong chemisorption/surface reaction, and was almost independent of pH. In contrast, the soap adsorption on rutile decreased at high pH values. A simple physisorption plus hydrophobic interaction appeared to be the principal mechanism for the soap adsorption on rutile at moderate temperatures (below ~70(C), beyond which it may change to chemisorption through an activation process. Water wash, particularly under acidic conditions (pH 2-3), of the rutile particles treated with soap, will lead to a desorption of the soap from the rutile surface by forming an acid salt precipitate.

Jan 1, 1995

By M. Leroux, S. R. Rao, J. Kim, V. Gervais, J. A. Finch, G. Labonté, N. Macminn, M. Ounpuu

Collectorless flotation of sulphide minerals from Lyon Lake ore (Mattabi Mines Ltd.) has been studied both in the laboratory and plant. Among the four major minerals chalcopyrite showed the greatest response to collectorless flotation, followed by galena. Flotation of sphalerite and pyrite was minimal. Collectorless flotation was influenced by pulp potential and pH. Experiments using different gas compositions showed collectorless flotation was promoted when the pulp potentials were greater than about 0 mV (SCE). The study of the effect of depressants showed that SO2 at pH < 8.0 depresses both galena and chalcopyrite but at pH 9.5 flotation of chalcopyrite recovers. Use of NaCN preferentially depressed chalcopyrite compared to galena. Preliminary results from plant tests at Mattabi Mines Ltd. confirm that collectorless flotation occurs and that it is preferential for chalcopyrite and to a lesser extent galena. Practical implications of collectorless flotation in plant practice are discussed. A critical factor will be silver recovery.

Jan 1, 1989

By D. Sotiropoulos

In the recent years, the mining sector is looking for specific indices, taking into account economic, environmental and social criteria, in order to meet the sustainable development requirements. In the present study traditional and environmental sustainable indices used in the Agios Dimitrios Power Plant, Northern Greece, are compared to those of ESKOM Company, South Africa, taken as reference. These indices are referred to, a) the solid fuels consumption, such as lignite, and, b) the emissions to the atmosphere, such as SO2, NO2 and dust. Last five years data show a remarkable improvement of all indices in the Agios Dimitrios Power Plant. Although the lignite used in this Power Plant is by far of poorer quality than that used by ESKOM - net calorific value 1272 and 4638 kcal/kg, respectively - dust emissions in both Power Plants are similar (52 and 31 g/kWh, respectively). The SO2 and NO2 emissions are very low in Agios Dimitrios compared to those of South Africa, respectively 1.92 and 7.91, and 1.74 and 3.61 g/kWh. This is mainly due to natural desulfurization (by the lignite?s calcium content) and the low NOx burners.

Jan 1, 2003

By Clark J. Gilbert

The mining method at the Cannon mine uses heading and bench stopes, which are subsequently backfilled with cemented high-strength fill before pillar removal. The dimensions of the pillars are 7.3 m wide by 19.8 to 28.9 m high (24 ft by 65 to 95 ft). They require careful blasting in order to not damage the rock, compromising pillar strength and complicating later removal. Additionally, the proximity of dwellings makes vibration control a must for good neighbor relations. A blast monitoring study was conducted in order to optimize bench blasting practices to maximize fragmentation, reduce costs, and to minimize wall damage and ground vibration. The Cannon mine is a joint venture between Asamera Minerals (US) Inc., a 92% owned subsidiary of Gulf Canada Ltd., and Breakwater Ltd. Asamera is the operator. The mine is located at the south end of Wenatchee, WA, a town of roughly 45,000 people on the eastern flanks of the Cascade Mountains. Gold is the primary product at the mine. The rock is extracted using a sublevel end-slicing method on 15 m (50 ft) lifts, with subsequent backfilling and pillar removal. The stope widths, dictated by rock conditions at 7.3 m (24 ft), are the same in the primaries as in the pillars, or secondaries.

Jan 1, 1990

By James S. Redpath

INTRODUCTION Background Early in 1972 our firm was asked by Cominco, managers of Arvik Mines Limited, to carry out an underground exploration programme referred to as the "Polaris Project" on a zinc-lead deposit in Canada&apos;s High Arctic. We had carried out numerous projects in the far north but this was to be the first long decline driven in perma-frost. Despite the short notice it was possible to meet the quickly approaching summer shipping deadline. We were able to do this by drawing heavily on our own and Cominco&apos;s background in Arctic operations. The project was an excellent example of owner-contractor co-operation and this spirit was responsible for the success of the project. Unusual Aspects There were a number of unusual aspects of the Polaris Project which are discussed in this paper. The extremely remote location, the short shipping season, and the fact that the work was carried out in permanently frozen ground, when combined with the lack of handy fresh water and a very severe climate, make it unique in many respects. Despite these handicaps, a record was set during the driving of the exploration decline.

Jan 1, 1974

By J. E. Hoffman, T. J. Keefe, Michael E. Stout, O&apos

M.A. Industries, Inc. has developed and is now offering on a commercially available basis, complete systems to recover and recycle lead from spent SLI batteries. The system begins with the breaking and separation of the component parts of the batteries and subsequent treatment of the effluent water produced by this operation. The recyclable materials recovered from this process are metallic lead, lead paste and polypropylene. The lead paste is introduced into a process to convert it from a lead sulfate to a lead carbonate. The process also regenerates the salt solutions into reusable carbonate. The lead carbonate is then leached into an acid bath where it is later recovered by a proprietary electrolytic process. The metallic lead is recovered in a short rotary furnace producing metal for further refining and alloying. The polypropylene is further washed and then introduced to a reclaim extruder along with the proper modifiers and additives. The resulting resin can then be sold on the open market to injection molding processors. This complete system greatly reduces the amount of waste to be disposed of and completely complies with all applicable EPA guidelines.

Jan 1, 1993

By Juan P. Camus

One of the most important decisions in mine development is the selection of the mining method. Open pit or underground methods are selected depending on the shape of the deposit, and its position with respect to the surface. When the decision is not clear or evident, then the common rule is to compare underground and open pit projects to choose the one which yields the maximum return. However, in some circumstances&apos; the best alternative is to start-up the operation with an open pit until a point where mine operating costs make more convenient to employ an underground method. In this case, the final pit limit is not directly related with commodity prices and its position is a funtion of capital and operating costs associated with both methods. The goal of this paper is a mans of establishing the proper ultimate pit considering a potential underground mine. The methodology is quite simple and can be implemented to work with a variety of available routines for pit optimization, such as Lerchs-Grossmann, floating cone, network flow and the Lemieux moving cone optimizing algorithm, which is the tool used by the author.

Jan 1, 1992

By Keith Whiting

The Van Stone zinc-lead mine is located in northeastern Washing- ton in Stevens County. It is about 24 km (15 miles) south of the Canadian border and 48 km (30 miles) west of the Idaho line. The deposits occur in late Cambrian age limestones and dolomites of the Metaline Formation. The bedding controls the trend of the zones containing the lenses of zinc-lead mineralization. The Van Stone property and vicinity is almost entirely covered with glacial drift averaging perhaps 6 m (20 ft) in thickness. Outcrops are very sparse. Outcropping gossan with zinc mineralization was first discovered by George Van Stone in 19 13, in what is now known as the South Ore Zone. Only minor trenching was done at that time. The property was idle until the mid- 1920s when Hecla Mining Co. drove several short adits and performed minor diamond drilling. In 1938, Willow Creek Mines of Nevada Inc. acquired the Van Stone plus adjacent parcels and commenced drilling on the known South Ore Zone. In the course of an expanded drilling program, the nonoutcropping North Ore Zone was discovered and was drilled out along a N30°E strike for about 305 m (1000 ft), beyond which point no mineralization was intersected.

Jan 1, 1991

By L. Xu, S Jones, R. Bhaskar, J. McKenzie

The objective of this project was to optimize the ventilation parameters of a continuous miner underboom scrubber. This would result in further control of the amount of airborne dust discharged during mining, reduce the exposure of face personnel for an exhaust brattice ventilation system, and avoid recirculation of contaminants at the face. This research was performed in an underground coal mine in Utah. The tasks performed included preliminary face ventilation evaluation, and optimization of the scrubber system to eliminate recirculation of the scrubber discharge air. Airflow tests were conducted on the currently used dust control system and the modified scrubber system. Tracer gas tests were performed to evaluate face ventilation effectiveness. Confirmatory tests of the scrubber system under actual operating conditions, modifications to the scrubber system and a comparative evaluation of the scrubber system vs. the existing system were performed. This paper presents the results of the airflow pattern tests and the respirable dust levels in the modified scrubber system and the existing system. The optimized face ventilation parameters and the developed operating guidelines may provide the benefits of dust reduction, better lace ventilation and improved visibility.

Jan 1, 1994

By P. H. Lu, M. J. DeMarco, J. R. Koehler

Beginning in late 1985 and continuing through 1987, US Bureau of Mines personnel investigated longwall chain pillar and entry design in two and three-entry gateroad systems at a deep underground coal mine in central Utah. To evaluate their respective stability characteristics, four chain pillars and two longwall panels within the two separate entry systems were instrumented with Bureau hydraulic borehole pressure cells to continuously monitor vertical and horizontal pillar and panel stresses through adjacent panel retreat. In addition, supplemental entry closure information was obtained from sites located in the vicinity of the instrumented pillars. The findings presented in this report demonstrate the practicality of evaluating mine pillar stability using in situ methods and support three significant conclusions regarding ground control aspects of the investigated two-entry system: (1) Total areal entry loading was considerably less for the two-entry system, as opposed to the three-entry system, (2) a smaller percentage of opened ground in the two-entry system contributed to a marked reduction in rooffalls, and (3) lower areal loading in the two-entry system suggests improved ground conditions when mining the underlying seam.

Jan 1, 1987

By C. Maltesh, P. Somasundaran, G. A. Gruber

Anionic conditioning of phosphate ores prior to fatty acid flotation is a critical step that determines the selectivity, recovers and, hence, the economics of the process. However, the chemical mechanisms operating during this conditioning step are not very well established. In this work, a comprehensive surrey of plant practice was conducted. Then, adsorption on flotation feed and francolite were studied under simulated plant conditions. Different adsorption mechanisms were found to be dominant under laboratory and plant conditions. In plant water, there was sonic physisorption of oleic acid on phosphate flotation feed and francolite, in addition to chemisorption. However, in distilled water under laboratory conditions, only chemisorption was detected. Fuel oil reduces the residual oleic acid in solution after adsorption, which explains the beneficial role of extender in phosphate flotation. The dissolved species in solution arising from the flotation feed or plant processing water are shown to clearly play a major role in determining the adsorption of oleic- acid on the substrates. The study also specifically demonstrates that, for the results to be used commercially, it is important to conduct the tests under plant mixing conditions and with the same plant water chemistry.

Jan 1, 1997

By L. M. English, Y. J. Wang

When plotted as head vs. volume, fan curves start high and decrease with increasing volume, while mine head curves start low and rise with increasing volume. Their intersection is the system operating point. However, as every ventilation instructor knows, the fact that head loss is a negative number (debit) and fan head is an energy addition (credit) is often a stumbling block to student or audience comprehension since the curves seem to reflect the opposite. It is possible to use the intuitively correct curves- pressure losses as negative values and energy additions as positive values - and still obtain the correct operating point. Adding the two curves produces a third curve that intersects the x-axis at the operating point, the point at which the fan energy input exactly matches air circulation energy loss. Using this technique also makes it easier to account for outside influences on the system, such as natural ventilating pressure. With the standard approach, it is quite easy to add or subtract such influences to the wrong curve. This approach can be extended to the graphical solution of any series/parallel ventilation network. The results are the same, and the approach is logically consistent and less confusing.

Jan 1, 1999

By J. A. Chermak, D. D. Runnells

Sulfide-bearing waste rock, ore and tailings have the potential for generating acid rock drainage (ARD) when exposed to an oxidizing environment. The possibility exists of utilizing the acid produced to react with lime and/or limestone to form a self-sealing cap on the reactive waste rock and tailings. Laboratory column experiments were conducted using acid-generating waste rock with a surface amendment of limestone and/or lime. Artificial rainwater was introduced and allowed to drain through the columns. Results demonstrated that the limestone and lime reacted with the acidic rock, resulting in the precipitation of a hardpan layer of gypsum and amorphous iron oxyhydroxide at the surface. The hardpan layer significantly reduced the effective permeability of the column. Based on the results of this study, it should be possible to create hardpan layers as chemical caps to significantly reduce the infiltration of rainwater and snowmelt into acidic waste rock or tailings material in the field. Unlike traditional capping methods, e.g., clay and high-density polyethylene (HDPE) covers, chemical caps should be self-healing.

Jan 1, 1998