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By D. H. Carlson, J. H. Johnson, C. F. Renders

Research was conducted at a western coal mine on a wide variety of underground mining vehicles to develop testing procedures for portable instrumentation monitoring of tailpipe concentrations of diesel particulate matter (DPM), carbon dioxide (CO2) carbon monoxide (CO) and nitric oxide (NO). DPM was measured using the Emissions Measurement Appa¬ratus (EMA) developed by Michigan Technological University (MTU), and an ECOM-KL five-gas analyzer was used to measure gaseous tailpipe concentrations. Baseline concentrations of the tailpipe pollutants were measured using vehicle systems to load the engine. Concentrations before and after the water scrubber were measured and water scrubber efficiencies were estimated by calculation. Field measurement procedures were established. Heavy-duty vehicles with automatic transmissions were loaded using the torque converter to stall the engine. Consistent engine loading for light-duty vehicles with manual transmissions involved placing the transmission in neutral and adjusting the throttle to maintain a constant engine speed of 2,500 rpm. Tailpipe CO2 concentrations for Caterpillar 3306 and 3304 engines were compared to laboratory CO2 data from Caterpillar and MSHA to help determine if engine settings were correctly adjusted for operation at high altitudes. (Perfect agreement between the mine vehicle tailpipe and laboratory measurements would not be expected because of the differences in the test conditions.) DPM concentrations for light-duty vehicles ranged from about 20 to 160 mg/m3, and one light-duty vehicle averaged near 1,000 mg/m3. DPM concentrations for heavy-duty vehicles ranged from about 55 to 200 mg/m3. Widely ranging DPM concentrations for a particular vehicle type reflect the state of maintenance, fuel rate settings and different engine loading procedures as well as differences between samples collected upstream and downstream of the waterscrubber. The calculated DPM removal efficiencies due to the water scrubber varied considerably between vehicles, ranging from 13% to 51%. Calculations indicate that, under worst-case conditions, very large reductions in DPM may be required to meet the proposed DPM PEL of 0.15 mg/m3, even on vehicles with water scrubbers. In-mine ambient air studies, which are needed to actually measure the impact of the tailpipe concentrations on the work environment and the effect of mine ventilation on the dilution of DPM were not done in this first set of tests.

Jan 1, 2000

By R. Q. Honaker, D. P. Patil, A. Sirkeci

Because of increasing production of fine coal during mining over the past century and because of inefficient fine-coal recovery technologies, a vast reserve of high-quality coal now exists in refuse ponds. A novel finecoal circuit, consisting of a hindered-bed classifier, an enhanced gravity concentrator and a flotation column, was evaluated for the recovery of fine coal from refuse ponds. The treatment of a pond derived from Pittsburgh No. 8 seam coal resulted in the production of a premium fuel containing less than 5% ash and a calorific value of about 30,170 kJ/kg with 60% mass yield. Results from the treatment of two refuse pond materials are presented in this paper.

Jan 1, 2002

By J. A. Organiscak

This paper examines methods for limiting occupational silica exposures for roof-bolting personnel in underground coal mining. A canopy air curtain and an air tube were evaluated as means to provide filtered air over the breathing zone of these personnel. Laboratory testing showed that dust reductions beneath the air curtain and air tube approached 60% and 40%, respectively, with low interference air velocities. The data also showed that dust reductions were highest for positions closest to the device and that these levels decreased with distance. This paper also evaluates a metal rake, a flexible insert and a rigid insert for cleaning the roof-bolter dust collector box. Less dust was produced when using the rigid insert. Surprisingly, the flexible insert was sometimes no better than scraping or raking the dust onto the mine floor. However, little dust got on the workers coveralls when using either of the inserts.

Jan 1, 2003

By R. Krishna, L. A. Kumar

The paper suggests a new empirical model for predicting mining subsidence. The parameters considered are Lithological Factor, which in this context meant percentage of sandstone, Rock Mass Factor (depending upon the RQD value of drill-hole cores), width: depth ratio and percentage extraction of coal. More than 250 drill-hole cores from seven longwall panels and 11 bord-and pillar (room-and-pillar) workings were analyzed from an extensive data bank of Singareni Collieries Company Ltd. (S.C.Co.), Andhra Pradesh, India. Excellent subsidence agreement was found with the suggested model.

Jan 1, 1993

By Frank F. Aplan

Introduction Gravity concentration may be defined as that process where particles of mixed sizes, shapes, and specific gravities are separated from each other by the force of gravity or by centrifugal force. The nature of the process is such that size and shape classification are an inherent part of the process in addition to separation on the basis of specific gravity from whence the process got its name. Mother nature has long practiced this form of mineral concentration by concentrating such heavy and relatively indestructible minerals as gold, platinum, cassiterite, ilmenite, zircon, and diamonds in placer or beach sand deposits. Once freed of their host granitic or other rock through natural weathering processes, these minerals are then subjected to stream or wave action producing a natural classification and concentration of the heavy minerals. Gravity concentration dates back to antiquity and was certainly the first ore concentration process used when selective mining and hand sorting would no longer suffice to produce the quality of concentrate desired. Forerunners of the present day sluice box and panning techniques were undoubtedly used by the ancient Egyptians on the upper Nile to separate gold from stream gravel. By the second century BC the extraction of gold from veins in quartz was well detailed by Agatharchides, but there is evidence that gold was brought into Egypt from the south as early as the XI1 Dynasty (~1900 BC).1 Most assuredly gravity concentration devices were used during the later Bronze Age to separate the heavier tin and copper minerals from their lighter gangue minerals. The Athenians used an elementary form of Rowing film concentration at their lead-silver mines at Laurium,2 and elementary jigging using wicker baskets was also probably developed at this time. Agricola's famous treatise De Re Metallica3 demonstrates that by the 16th century gravity concentration technology was well advanced and a large number of devices had been developed. Chinese

Jan 1, 1985

By E. B. McNew, J. M. Barnes, A. E. Torma

The applicability of biosorbent materials for the removal of uranium and other heavy metals from synthetic and actual uranium mil 1 tailing (UMT) solutions has been investigated. The biosorbent materials used in this study were barium loaded beads of alginate, alginate-dextran sulfate, alginate-carrageenan, and alginate-xanthan gum. These studies were performed in stirred vessels and packed columns. It was observed that 100 percent of the uranium could be removed from a synthetic solution following 2 hours of contact time in a stirred vessel, and 80-100% of U, V, Mo, Mn, Sr, and Zn could be removed from a UMT effluent solution with a packed column. Kinetic evaluations were performed, using a generalized rate equation, on the biosorption of uranium with these barium loaded beads.

Jan 1, 1992

By Eric Monrad

Discrete event simulation modeling provides a tool to quantify the throughput capacity of stockyards. Interactions between the main equipment types (trains, dumpers, conveyors, stackers, reclaimers, shiploaders) can be captured, including route blockages, breakdowns, and planned maintenance. Simulation has been successfully used at world-class stockyard facilities to determine current capacity and to identify gains resulting from improvement projects. Recent projects have focused on iron-ore, coal, and soya facilities, but the technology is suitable to be used on any bulk material type.

Jan 1, 2008

By Eric Jackson

The presentation describes the operation and field test results of a seafloor massive sulphide prospecting system. The prospecting system is deployed from a work-class ROV, and it features a new and innovative electromagnetic ocean floor conductivity sensor. It also includes magnetometers, a multibeam sonar, and subsea cameras. The prospecting system has been used in two exploration campaigns - one in the territorial waters of Papua New Guinea (PNG) in 2007 and again in 2008 in both PNG and Tonga waters. The 2007 campaign used the prototype sensor, and the 2008 campaign used a Mark II version. Correlations between drill core samples and EM conductivity results are excellent. New prospecting system data will be used to help plan future core drilling locations. The presentation discusses the principle of operation of the EM conductivity sensor, discusses improvements made in the EM sensor and the overall prospecting system, and shows exploration results. Keywords: seafloor massive sulphide, geophysics, ocean floor, subsea, electromagnetic, conductivity, magnetometer, multibeam, core drilling

Jan 1, 2008

By P. Venkatasubramanian

The aerospace and nuclear industries have been applying systematic techniques for assessing the safety of complex technical systems for many years. These techniques such as fault tree analysis, failure mode, and effect analysis, etc., and more recently "expert systems," were developed to formally evaluate systems safety and to determine how hazards can he reduced. The application of formal methods such as expert systems has the potential for further reduction in both frequency and the consequences of mine accidents. This paper presents a general expert system model of diagnostic reasoning and describes its use as an inference method for analysis and problem identification for accidents due to the presence of an open cycle diesel-powered mine cars in underground coal mines.

Jan 1, 1987

By J. R. Johanson

Many solids processes that look feasible on paper or even in pilot studies become disasters in full scale. Changes in solids flow characteristics from pilot scale to full scale because of larger so lids contact pressures, thermal shocks or unforeseen temperature excursions often cause full scale solids flow problems not encountered in the laboratory or pilot studies. Fortunately, proper applications of solids flow principals and solids flow property measurement at full scale conditions can anticipate the problems and thus provide an accurate basis for full scale design or existing plant modifications.

Jan 1, 1988

By Brendan Parker, Joseph Skrypniuk

Boddington Gold Mine1 (BGM) commenced production in 1987 and is currently ranked as the second largest gold producer in Australia. In a strategy to improve plant efficiency, constraints to plant performance were identified and prioritised with a view to maximising benefit for minimal expenditure. After identifying that leach kinetics and circuit residence time were major constraints, the introduction of oxygen was identified as having the greatest potential for the delivery of sig­nificant cost benefits. The application of oxygen, initially by conventional tech­niques, and subsequently by installation of Atomaer's Filblast gas shear reactor, improved gold recovery, reduced the resi­dence time constraint and enabled higher mill throughput to be achieved. Additional benefits included operation at lower pulp densities and a reduction in reagent usage. A significant reduc­tion in unit operating cost resulted from these benefits. This paper quantifies the above benefits in a format accept­able to both metallurgists and accountants by integrating the findings in a techno-economic perspective.

Jan 1, 1996

By Qing Wang, Xiaochuan Xu, Jianping Liu, Xiaowei Gu, Qingyu Zhu

"The ecological costs related to the various optimized production schemes were calculated based on the designed ultimate pit. Moreover, the influence of the ecological costs on the selection of production schemes was discussed. In one designed pit, a series of geologically optimum pushbacks with sufficiently small increment were produced using the floating cone method founded on the principle of the highest metal content. Then all the pushbacks were reordered by the dynamic network diagram. The production scheme with the maximum NPV route was considered as the optimum one. The ecological impacts produced by mining were quantified and the ecological cost calculation models, which contain the direct eco-value loss, the indirect eco-value loss, the eco-restoration cost and the carbon emission cost were proposed. In one big open pit mine case, various production schemes were optimized and the one with maximum NPV was selected without taking into account the eco-costs. The scheme with the maximum comprehensive profit was obtained by calculating the eco-cost of each scheme. The results showed that the best scheme considered with the eco-cost was not the scheme with the maximum NPV. Therefore, the eco-cost presents the effect on the selection of the best production scheme.Introduction Optimizing production scheme is to determine the mining quantities of ore and rock, the pushing position of stope each year, and maximize the NPV of mine. In the theory, production scheming optimization has gone through trial and error (Pana and Carlson 1966), linear programming method (Johnson 1968), mixed integer programming (Gershon 1983), integer mapping (Kim and Cai 1990), dynamic programming et al (Gu et al 2014). In recent years, the study on production scheduling optimization has been focused on two aspects. On the one hand, the study is to solve the investment risk caused by the uncertainties of economic and geological environment (Ramazan and Dimitrakopoulos 2013, Marcotte and Caron 2010, Lamghari and Dimitrakopoulos 2012, Godoy and Dimitrakopoulos 2004, Benndorf and Shishvan 2014). On the other hand, the emphasis of the study was on reducing the problems for the optimization algorithm, to make it more efficient and practical (Cullenbine et al 2011, Shishvan and Sattarvand 2015, Askari-Nasab et al 2011, Nasab et al 2010). However, different production schemes cause different damage of mine land and pollutant emission, thus triggering environment problem. With the improvement of people’s consciousness of environment protection, the environmental issue of mining has been attracting more and more attention."

Jan 1, 2017

By D. R. Baughman

Copper oxide deposits that may be considered for in situ leaching exist in unique geologic settings, different from uranium deposits. A large number of interrelated factors must be considered in wellfield design. Many of these factors are hard to quantify and are directly related to geologic features of the orebody. This paper discusses some of the important factors in wellfield design and suggests an outline for a design procedure.

Jan 1, 1988

By S. B. Leonov, K. I. Popov, S. B. Polonsky

The offered technological line includes a flotation pulp air conditioner operating on the impact-mechanical effect and two column apparatuses with a descending pulp-air flow mounted in series. The technology developed makes it possible to increase considerably the valuable component in the concentrate simultaneously with a reduction in energy consumption for the flotation process. The experience achieved with the technology showed the possibility for obtaining sulphide silver-bearing ore superconcentrates with the noble metal content 2-10 times higher than that in the concentrates obtained by the conventional technology. The same results were obtained in the process of calcium-bearing boron-silicate ore-dressing.

Jan 1, 1995

By R. J. Matetic, Peter G. Kovalchik, Jeffrey Shawn Peterson

The National Institute for Occupational Safety and Health (NIOSH) has initiated a study of a roof bolter to reduce noise exposure to mine roof bolter operators. An important segment of this research entails determining the affect of various drilling configurations on the performance (penetration rate) and sound power emissions when drilling into granite. Test conditions included various combinations of rotational speeds and thrusts; hex and round drill steels of one inch (1.) and one and three-eighths inch (1 3/8.) diameters; vacuum and wet conditions; and using drill media of differing compressive strengths. This paper will detail the affects of each of these on the performance and sound power level emission. When drilling into granite, it was found that wet drilling generated lower sound power levels and performed better than vacuum drilling.

Jan 1, 2005

By V. R. Degner

Comments Summary It is very interesting to review the technical changes which have occurred in the industrial practice of minerals flotation over the past two decades. In 1972, worldwide industrial flotation was dominated by 'mechanical' flotation machines having an individual cell volume less than 500 cu.ft. Manufactures, such as DENVER Eqpt. Co., OUTOKUMPU, WEMCO, GALIGHER (AGITAIR), AKKER, and later DORR-OLIVER, produced flotation machines featuring a mechanical rotating impeller which served to mix pulp and air, prior to flotation, and to keep the solid ore particles in suspension. While sharing this common mechanical impeller feature, the machine design of the various manufactures differed in detail; particularly in regard to the vertical location of the impeller in the cell and the means by which flotation air was brought into contact with the pulp within the rotor mechanism. A review of the existing technical literature in 1972 would identify academic research studies, particularly at Columbia University (N. Arbiter, C, Harris ...) aimed at comparing flotation cell design concepts, of the various machine manufactures, on a hydrodynamic basis. These research studies were confined to very small, laboratory bench size, flotation machines, and the benefits of incorporating hydrodynamic considerations in the scale-up of the existing 300 cu.ft. mechanical flotation technology to larger cells was not commonly practiced industrially. Technological advances in minerals flotation, over the past two decades, have been influenced by a variety of economic factors including the increasing development of lower grade ore bodies, the attractions of producing a higher grade final concentrate, and the economy of tails retreatment to improve overall plant recovery performance, and flotation system “optimization" became increasingly important through the 1970-80 time period. The trend toward processing lower grade ores led to higher tonnage mill operations, and stimulated the development of the very large capacity mechanical flotation machine for roughing and scavenging duty. In 1972, the 500 cu.ft. size flotation machine was being pilot tested and introduced to the industrial market. Today, 1993, individual cell volumes of 1500-3000 cu.ft. are operating successfully throughout the world, and well planned plant test programs have concluded that the very large flotation machine can achieve the same metallurgical performance level of its smaller predecessor. The large flotation machine development record clearly credits the incorporation of internal cell hydrodynamic considerations in guiding the scale-up of the mechanical flotation machine to large sizes. This guidance eliminated, or reduced significantly, costly in-plant prototype machine changes which increase Dramatically with increasing flotation machine size. Early in the 1980's, at approximately the time that flotation machines in the 1500 cu.ft. class were being introduced into the market, it became evident that the availability of the very large mechanical flotation machine brought with it the need for a systematic means to "optimize" the flotation system by relating flotation cell size, row length (i.e. number of cells per row), and flotation rougher, scavenger, and cleaner system configuration to the economic objectives of the concentrators' operating management. Flotation system optimization consists of quantifying the flotation process performance using a suitable model which relates the kinetic response of the trace specie and the gangue material to the cell overflow, and produces a numerical relationship between product grade and value recovery. The computer analysis technique has proven to be an invaluable tool in determining the kinetic model coefficients which characterize a given application, and is also used to apply the resulting model to a proposed minerals beneficiation situation seeking to "optimize" the flotation system by relating metallurgical grade-recovery performance, flotation cell size, and circuit arrangement, to plant space, installation, and operating costs. It is interesting to note that these same computer based kinetic flotation analysis techniques can be easily applied to quantitatively evaluate the effect of different chemical reagent strategies, and flotation air transfer, on process performance for a variety of candidate feed ore types.

Jan 1, 1993

By M. S. Klima, M. Fofana

The use of a laboratory-scale magnetic fluid-based separator for coal separations was examined. A Frantz laboratory magnetic separator was modified by fabricating new pole pieces of the appropriate geometry to provide the proper magnetic field gradients. Two separation chambers, which were constructed of Plexiglas, were designed to fit between the pole pieces. A commercially available, water-based, ferromagnetic fluid was used as the separating medium. The separating density was changed by varying the current intensity of the electromagnet coil. Both batch and continuous separations were made using 0.59 x 0.50-mm and 0.18 x 0. 15-mm coal. The results are compared to those obtained using organic liquids.

Jan 1, 1998

By S. Subbarayan, S. Chander, M. S. Klima

A laboratory study was conducted to investigate the potential for recovering anthracite from coal preparation-plant tailings. The study included washability analyses, cyclone simulations and froth flotation testing Samples were collected from either the tailings streams or the slurry ponds of five anthracite-cleaning plants. From each sample, a washability analysis was conducted on the 28x100 and 100x200-mesh fractions. Using the above data, along with published partition data, simulations were performed with various cyclone-staging arrangements for both water-only and dense-medium cyclones treating the 28x200-mesh fractions. Separate froth -flotation tests were conducted on the 28x100- and 100x200-mesh fractions from three of the plant samples. The washability, simulation and flotation results are presented as grade-yield curves.

Jan 1, 1996

By J. B. Pautler, A. E. Gross, M. G. Strominger

The U.S. Bureau of Mines research on the use of cement as an agglomeration aid allowed precious metals heap leaching to become an economically viable method of precious metal recovery during the 1980's. However, many agglomerated ore bodies still exhibited poor heap/agglomerate strength. Precious metal recovery was often too slow or required prohibitively high levels of cement to be economically sound. Problems with heap ponding, blinding, and solution channeling and "wash-out" indicated that there was a need within the industry to improve on existing agglomeration technology. An in-depth research effort was undertaken to satisfy this need. Three years of research led to a patent on the use of vinyl addition polymers as effective agglomeration aids. A close working relationship between Brewer Gold and Nalco Chemical Company aided in the development of this program. This paper details the pilot test work, the full-scale evaluation at Brewer Gold Company, and conclusions.

Jan 1, 1990

By Michael G. Strominger, Anthony E. Gross

The development of precious metals ore agglomeration with a cement binder, by the U.S. Bureau of Mines, has allowed the economical heap leaching of low grade gold ores (<0,05 oz/ton) over the last decade, Even with the Bureau of Mines technology, numerous operations continue to experience channeling and blinding problems. A research project was undertaken at Nalco Chemical to address situations where improved agglomeration is needed, By increasing the incorporation of fines into the agglomerates,the segregation of ore by size which occurs from handling will be reduced and channeling minimized. A stronger agglomerate will reduce fines migration during leaching and prevent blinding of the heap, Both of these changes will give an even flow of barren solution throughout the heap and give solution contact with all of the ore. This paper presents the development of polymeric agglomeration aid, Nalco 9760 which has given a higher rate of and a higher total gold recovery in plant evaluations.

Jan 1, 1990