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By J. Noll, A. Miller, J. Volkwein, C. Pritchard

Hecla Limited, Magee Scientific, and NIOSH have combined efforts to evaluate an in-situ air filtration system for use in an underground mine environment. The purpose of the collaboration was to determine the efficacy of such a technology for reducing the concentration of airborne diesel particulate matter (DPM), with the aim of improving air quality in underground hardrock mines. A secondary goal was to evaluate the use of an Aethalometer as a means of real-time measurement of black carbon as a surrogate for DPM. The evaluation included measuring the DPM-capture efficiency of the filter when it was pre-loaded with dust. Toward this end, rock dust was introduced at the filter inlet to create a dust layer on the filter surface, with the intent of providing improved capture of the much smaller DPM particles. The filtration efficiency for DPM was assessed by comparing measurements of DPM taken at the inlet and outlet of the system, using both real-time and time-weighted-average approaches. The real-time measurements were performed with the model AE33 Aethalometer® made by Magee Scientific. The results of the NIOSH 5040 method analysis were used to assess the effects of the system on time-weighted-average concentrations of total carbon. Results showed a reduction in DPM concentrations in the range of 82%-89%. While the calculated efficiencies based on the two different measurement methods were similar, the DPM levels reported by the Aethalometer were higher, possibly due to differences in the performance of the size-selectors used for the two methods (impactors versus cyclones). More research is required to develop a robust correlation between the two methods, to support the use of the Aethalometer for future mining applications. The advantage of the Aethalometer is that it can measure and record DPM levels for weeks at a time, and can be directly connected to a mine monitoring system, potentially at multiple locations. Ideally such data can be used to initiate the startup of the filtration system should DPM concentrations reach an action level. This work demonstrated that in-situ filtration systems, modified to collect DPM and coupled with real-time monitoring, show promise at reducing DPM concentrations in the mine environment.

Jan 1, 2016

By A. Wang

This paper defines the elements of a basic economic model for decision-making when considering a methane drainage system for an underground coal mine. A drainage system will require significant capital and operating expenses; hence the decision to utilize drainage must be made carefully. The model outlines the basic structure of decision-making and considers the costs and benefits when the methane is marketed and when the methane is vented to the atmosphere. The effects on mine safety and the dust levels in the mine are also considered, both in a general format and as economic variables. Sources of information for executing this decision-making are provided for an actual mine decision.

Jan 1, 1997

By Kadri Dagdelen

The importance of factoring mining dilution into feasibility stage ore reserve estimates is discussed. An example that relates the issue of mining dilution to the size of smallest volumes that can be mined selectively is given. Relationship between the size of the selective mining units (SMU's) and the variance of their average grade is presented. The concept of variance reduction and its use in factoring mining dilution into geostatistical ore reserve estimation is described. An approach to estimate variance reduction factor by way of conditional simulation is introduced.

Jan 1, 1996

By Martin H. Stanczyk

In recent, years the demand and consumption of finely ground industrial minerals has substantially increased for such uses as fillers and chemically reactive components. The size, specifications for these types of industrial mineral materials vary to a great extent and depend on the particular end purpose' and on the physical properties of the mineral itself. Size reduction of industrial minerals usually is obtained by conventional crushing and grinding methods. However, some specialized milling techniques have been developed for producing these minerals in extremely fine particle size ranges. During recent years the Bureau of Mines has been investigating an attrition grinding method to produce ultrafine subsieve-size mineral particles. The Bureau developed process, which has been patented,2 comprises the intense agitation of a slurry composed of the material to be ground, a relatively fine granular grinding medium, and a suspending fluid. The process has been shown to be effective for the comminution of kaolin in the particle size range of 2 microns and finer on a batch3 and continuous basis.4,5 This report presents the results of batch tests made to determine the effectiveness of the attrition grinding process for comminuting commercial products of (1) mica, a tough lamellar material, (2) fluorite, a brittle intermediately hard material, and (3) barite, a relatively soft, massive material.

Jan 1, 1967

By John Marshall

Silverton was the queen city of the western mining towns in the early 1900s. Located high in the San Juan Mountains, the town constantly grew and changed. Yet, it was subject to the vagaries and whims of economics, politics and disasters, natural or otherwise. Breweries, smelters and sawmills serviced Silverton's swelling mining population, which reached several thousand at its peak. Two trains a day ran from Durango to Silverton, in addition to trains running from Silverton over the top of Red Mountain on to Ironton. They ran up Cement Creek to the little town of Gladstone and up the Animas River Valley to Howardsville, Eureka and Animas Forks. During these prosperous times, construction flourished. There were plenty of wooden structures, and many of these stand today. The first brick buildings were built by bricklayer Patrick Stanley in 1877. It took quite a while for the first car to arrive. Almost 28 years passed from the coming of the first train to the arrival of the first car. It was brought over 3,840-m (12,600-ft) Stony Pass from Creede, CO, in an incredible journey retold years later by Louis Wyman. "Dad's daydreams were not the idle musings or the fantasies of a mystic," Wyman said. "They had a way of erupting into reality. He advocated and built good roads," he said. "During the summer of 1910, he was up to his sweatband in a project that took in half the state of Colorado. He envisioned an automobile highway, unheard of at that time, running southwest from Denver through the scenic grandeur of the high Colorado Rockies. The road would traverse a thousand miles or more of the state's finest recreational land finally circling back to Denver. Years later, when all of the county roads had been connected, it became known as 'Colorado's Thousand-Mile Circle Route.' Of course, Silverton and the San Juans were bright stars along the way."

Jan 1, 1997

Disposal of solid and liquid wastes from mining and milling operations has become a focus of attention in recent years. Consequently, the geotechnical engineer is more frequently associated with design of disposal facilities. Jack Wulff, a representative of one consulting firm with experience in this field, talks with ME about the geotechnical engineer's contribution. Mr. Wulff, mine and mill waste disposal today is receiving more attention-and many more dollars-than in the past. Regulatory agencies have promulgated demanding requirements concerning mill waste (especially uranium mill waste) and specialist consultants are frequently being called in to design disposal systems. What can the experienced geotechnical engineer add to the development of waste disposal facilities? It's true that geotechnical engineers have recently become more visible in the minerals sector, but we've been around mining for a long time-as foundation engineers for mills and mine support buildings, and for geotechnical aspects of open pits, pipelines, railroads, roads, and so forth. We've also designed water supply dams, which could be considered recursors of tailings dams and other forms of disposal systems. Let me show by example what geotechnical engineering can contribute to waste disposal facility design. I recently was asked to look at several small wastewater impoundments which had failed. The design of the earth embankments appeared, at first glance, to be rather conservative. They were only about 3.4 m high, the slopes were 3 to 1 (horizontal to vertical), with about 24 m of bottom contact with the earth foundation. But there had been three episodes of dike failure in a few months, all upon initial filling. The problem was the nature of some material in the foundation that was also used as structural fill-a dispersive clay that readily deflocculated and eroded on contact with water, especially with seeping or flowing water. The design did not include the defensive measures required to use such materials confidently in water retention structures. Apparently, the designer did not recognize the potential problem posed by the unusual soil characteristics. That's the sort of engineering information fundamental to geotechnical engineering, but not necessarily a part of the civil, structural, or mining engineer's professional training or experience. This difference in expertise is not simply a matter of factual knowledge-it also affects the design process. The structural engineer can design a structure to fit the client's functional needs and can specify the materials (grade of steel, PVC, concrete, etc.) to meet the demands of the design. The geotechnical engineer's design process is somewhat different, since we work with natural materials, not man-made materials produced according to specification. We first have to establish what kinds of materials are available (usually directly from the chosen site, since importation of materials becomes expensive). Then we determine the engineering properties and characteristics and, finally, design the structure to fulfill the client's requirements within parameters dictated by available materials. In brief, the geotechnical engineer works with naturally-evolved, not man-made, materials and uses design techniques developed to accommodate that fact. Because no two sites are exactly alike in configuration, structural (geologic) characteristics, or available materials, there will be unique design and judgmental questions to be resolved on virtually every project. You said that water retention dams could be considered the precursors of tailings dams-you probably had a specific technical relationship in mind. There's a very strong carryover of methodology from earth dam design, where the technology developed and where it has become very refined. In designing a tailings impoundment or similar facility, essentially the same procedures of field sampling are involved (with a geotechnical engineer or an engineering geologist directing the program since representative

Jan 7, 1980

By David D. Eyer

In today's world coal market, coal quality is becoming increasingly important. Often the coal quality parameters are one of the crucial considerations in the development of a coal mine. Because of the user's tighter specifications and because of strict environmental regulations, coal producers are being called on to predict with increasing accuracy, not only the quality of their product but also the variability of that quality. This area of reserve evaluation is naturally receiving a great deal of scrutiny. Consolidation Coal Company has developed reliable and sophisticated methods for predicting coal quality, but the company's efforts continue to search for even better techniques. The following is a step-wise summary of The methods currently used by consolidation coal company, with A recent project used as an example. Two of the newer, and as yet experimental techniques will be briefly discussed.

Jan 1, 1980

By Phillip J. Maddex

After the presentation of a co-authored paper, "The Cost of Transporting Ores and Raw Materials in World Markets", at the February SME meeting, one questioner commented, "You have been talking about the large shipper and ship loads. What does the small shipper do?" This paper will attempt to answer that question, at least in part. Probably the questioner hoped to hear about specific new tools and new techniques that he could apply. But one paper could only scratch the surface of the vast fund of information available; so rather than talk specifics we should take basics, that is, people, management and technology.

Jan 1, 1967

By F. B. Olender

Idler engineering, operation, and maintenance cannot be covered in depth in a short paper. Therefore, this will be a general look into the subject matter in light or the present-day technology. Depending on the source or reference used, belts for handling bulk material underground came into being between 1900 and 1920, while strip mining appeared in the thirties. The conveyor belt speeds in that era were in the 300 rpm to 500 rpm range. Belt speeds or 600-700 rpm were in vogue in the thirties, and the early sixties saw speeds or 800-900 rpm. Today, speeds or 1000 rpm are not looked at with dismay; in fact, speeds or 2000 rpm are being discussed. Among the driving forces moving the bulk materials handling industry to these greater heights have been the mining operators and engineers. Their appetite to increase output, yield, and reduced per-ton costs has constantly challenged the bulk material handling industry to develop products capable or handling these increased capacities. One or the products affected by this movement is the idler. Apart from the conveyor belt itself, it is one or the most significant parts or a conveyor system because or the sheer numbers needed in an installation.

Jan 1, 1971

By D. McCarthy

This paper discusses the process involved in developing an optimum method of treating and removing heavy metals from water that have leached out from the native rock -prior to discharge back into the environment. Also designed into the system is a manner to stabilize the metals removed as a precipitate, so that they can be disposed of as a non-hazardous waste.

Jan 1, 1992

By Harvey P. Knudsen

Case studies are presented in this paper to illustrate the usefulness and applicability of using conditional simulation in under- ground coal mine planning. Conditional simulation is a technique developed in the last five years that allows the building of a simulated ore body (or coal deposit) model. Construction and validation of the simulated model is described in order to show how well the model reproduces the essential characteristics of the deposit. In the model, the thickness, ash, and sulfur content are known everywhere in the deposit and each variable has the same mean, variance, and spatial variability (variogram) as that variable has in the real deposit. Use of the simulated deposit in the design of drilling strategy for long range mine planning is demonstrated in me case study. Determining the potential of short term production scheduling to reduce the fluctuations of sulfur in run of mine coal is described in the second case study.

Jan 1, 1980

By Ronald J. Vance

One of the key elements of change in the mining industry has been the ever-increasing integration and coordination of previously highly segregated business disciplines, the extent to which the marketing and finance functions have evolved and merged within the mining industry. If one listens to the language of mine product marketers today, one hears terms like contango, backwardation, forwards, options, min/max, synthetics, swaptions, caps, collars, FRA's, spot deferreds, double bottom, head and shoulders. The list is endless and a glossary may be out-of-date even before the ink is dry. No longer can a marketer of mine products get through the day and, more importantly, keep his or her job merely by reciting statistics on supply, demand, prices and the jargon of quotational periods, delivery and payment terms. Walk into the office of any marketing department today, and computer terminals spewing on-line market prices and instantaneous news retrieval command the attention of all who enter. Traditionally, mining companies, particularly those in North America, took a passive view toward marketing their products and an even more passive view toward management of price risk. The typical, albeit simplified, gold producer of the 1970s and early 1980s spent all of its energy exploring, delineating, developing and producing a product that was placed by the mine gate. Like magic, anonymous buyers took it away and left piles of dollars in its place. No fuss, no muss and nothing to get in the way of more exploring, delineating, producing etc. The typical copper producer, meanwhile, was slightly more creative. Copper producers still spent most of their energy exploring, producing etc., but they at least acknowledged the identity of their customers. Many even went so far as to fabricate finished mine products into shapes and sizes that their ultimate customer needed. Wire, cable, sheet and extrusions were all in forms ready to be purchased by power companies, motor manufacturers and telephone companies. But, while production and costs steadily increased, research and development into new expanding markets was funded by little more than lip service. Competitors and competitive products steadily eroded market share and realized prices. The now-famous Business Week magazine cover that proclaimed "The Death of Mining" was an imminent reality.

Jan 1, 1993

The purpose of this paper is to present validation studies of the mine-fire simulator using data gathered from an actual mine fire which occurred in November 1991 at the Pattiki Mine. To develop the model of the ventilation system with the fire in this validation study, the following adjustments were made: (1) flow and gas distribution in the entire ventilation network, and (2) fire parameters matching the data recorded by the monitoring system. After close correlations between simulation and real data were achieved, additional analysis of the ventilation system with the mine fire was performed. Presented and discussed in this paper are the following stages of the fire at the Pattiki Mine: (1) early fire (before the fire was detected), (2) preparation for and fire fighting with water, (3) fire sealing, and (4) fire extinguishing. This study evaluates the suitability of the computer software package for modeling underground fires. The paper also discusses the importance of the on-line monitoring system for the validation process.

Jan 1, 1995

By Toby Mayo, Tassos Grammatikopoulos, Massoud Aghamirian, MARK FEDIKOW

The Zoro pegmatite project in east-central Manitoba occurs 20 km east of the historic mining town of Snow Lake. A composite sample (Master Comp) was prepared fromthree pegmatite zones within Zoro Dyke “D1” including the North, Central, and South Zones for mineralogical analysis and heavy liquid separation (HLS). The mineralogical examination was conducted on a subsample crushed to ca. P80 of 600 μm to determine the overall mineral assemblage, liberation of spodumene, and assess the potential recovery of spodumene by flotation. XRD and QEMSCAN results show that the sample consists of spodumene (10.5%), quartz (29.3%), plagioclase (29.0%), K-feldspars (21.3%), micas (5.1%), tourmaline (2.9%), and Fe-Mn-phosphates (0.1%). Spodumene is well liberated (88%), but also forms complex particles (7%), and middlings with quartz (4%). Liberation of spodumene increases from 81 in the + 600 μm to 95%in the − 106 μm size fraction. Liberation of quartz, feldspars, and micas account for 89%, 94%, and 83%, respectively. Electron probe micro-analyses and LA-ICP-MS showed that the average Li concentration is 3.7% in spodumene, 2196 ppm in micas, 1001 ppm in tourmaline, and 115 ppm in K-feldspars. Thus, spodumene accounts for 96%, micas 2%, Fe-Mn phosphates 1%, and both K-feldspars and tourmaline for < 1% of the total Li in the sample. The mineralogical data indicate the potential to recover spodumene by flotation with minimal Li losses due to other than spodumene carriers. Heavy liquid separation was conducted on the Master Comp which was crushed to − 6.4 mm, while the − 600 μmfractionwas removed fromthis test. The coarse fraction − 6.4mm/+ 600 μmwas subjected to HLS tests with eight heavy liquid-specific gravity cut-points (2.65 to 3.10 g/cm3). HLS indicates that it is possible to produce a high-grade lithium concentrate (close to 6% Li2O) after the rejection of iron silicates with magnetic separation.

Sep 16, 2020

By Frank Agyemang, Zainab Nasrullah, Richard LaDouceur, Mehran Saddat

To sustain the circular economy, defence applications, and other renewable technologies, recycling rare earth elements (REEs) and other critical elements from their secondary resources is important. This cause has resulted in rigorous research and development for viable extraction and separation of REEs. Previously, Sm-Co recycling has been done with technologies, which fall under the categories of pyrometallurgy, physical separation, and hydrometallurgy. All these methods have limitations associated with energy, cost, and environment. Reportedly, the chemical leaching technology has successfully recovered and separated Sm-Co. Still, it has limitations associated with slow mass transfer and leaching kinetics, and there is a need to intensify the process to make it time efficient. This approach has also adversely impacted the environment by an extensive use of toxic, corrosive, non-selective, and expensive reagents. In this research study, chemical leaching of Sm-Co was performed using this new class of solvents, Deep Eutectic Solvents (DESs), which fall under the category of ion metallurgy. Four different DESs were used, proven to be green, non-toxic, biodegradable, cheap, and selective for cobalt over samarium by 82% leaching conversion. To improve the slow mass transfer and leaching time, this new technology of resonant vibratory mixing (RVM) was also tested. RVM intensifies mixing by establishing near instantaneous, low energy mixing conditions through resonance. It has been shown to improve the adsorption kinetics and was tested for the leaching kinetics. Four combinations of DESs were prepared, which are made up of two quaternary salts: Choline Chloride and Tetra Butyl Ammonium Chloride, and three organic compounds: Oxalic Acid, Urea, and Ethylene Glycol. These combinations were used for chemical leaching of Sm-Co with leaching factors of time, temperature, and type of DESs. After leaching, the samples were tested with and without resonant vibratory mixing with conditions of time, intensity (%), and type of DESs. Samples were analysed with Induced Coupled Plasma - Optical Spectroscopy (ICP - OES). Future work will involve a life-cycle assessment to assess the RVM technology with other conventional mixers, and an extensive study of DES properties to improve selective leaching.

Feb 1, 2025

By Michael W. Roper

McDermitt Mine is located in northern Humboldt County, Nevada, approximately 5 miles south of the Orgeon-Nevada line (Figure I), within the Opalite Mining District. The operation is a joint venture between Placer Amex Inc., San Francisco, and Mineral Exploration Company Ltd., a limited partnership. The McDermitt orebody possesses a discontinuous, gently dipping blanket-like form within 150 feet of the surface over an area 2200 by 2500 feet. The ore zone averages 20 feet in thickness. The ore minerals consist of cinnabar (HgS) and corderoite (Hg3S2C12) deposited parallel to bedding within argillized, Miocene age, tuffaceous lacustrine sediments. Exploration indicates reserves of approximately 3,000,000 tons ore at a grade of 10 pounds mercury per ton (0.5%) An open pit mining operation utilizing scrapers and bulldozers supplies a concentrator with 700 tons of ore per day. The milling operation consists of autogenous grinding, flotation concentration, concentrate dewatering, and tailing disposal, with a design capacity of 100 tons per hour. The furnace section consists of a concentrate filter, vertical six hearth furnace, mercury condensing system, and exhaust gas scrubbing systems. It has a design capacity of 1000 pounds of dry concentrate per hour. The McDermitt orebody is situated about 2000 feet north of the Cordero Mine which, with adjacent properties, produced over 115,000 flasks (76 pounds per flask) mercury from 1941 to 1972&apos; Two other major mercury producers in the district have been the Bretz and Opalite Mines, located in southern Malheur County, Oregon, within 5 miles of the Oregon-Nevada line. Bretz and Opalite have produced about 14,800 and 12,370 flasks mercury respectively, from 1926 to 1965.1/

Jan 1, 1976

By Bruce Richardson

A contractor-manufactured 4.75m (15&apos;-7") diameter EPB shield excavated a 115m (375 ft) long tunnel under the San Antonio River as part of the Salado Creek to Dos Rios Pipeline Interconnect Project in San Antonio, Texas. Lignite, limestone concretions, and sandstone in the face of the tunnel required the use of disc cutters. Less than 7.6m (25 ft) of sand and gravel hydraulically connected the top of the tunnel to the channel of the river. Fully lagged steel ribs with filter fabric were used for initial ground support and water control. This and other contractor manufactured TBMs in the 1.2 to 4.75m (4 to 16 ft) range are presented with descriptions of the jobsites, equipment, performances, and problems.

Jan 1, 2008

The height of permanent slopes at the Panguna mine of Bougainville Copper Limited will vary from 350 to 950 metres. A few degrees difference in slope angle has a large effect on the ore/waste stripping ratio. Optimum slopes can be achieved if longer batter slopes (exceeding 45m height) are excavated using bulldozers to trim parallel to controlling fracture surfaces. Unnecessary slope flattening by incorporating benches can cost millions of dollars in lost ore. Faults and other major weaknesses, which can result in wedge failure or erodible zones have been treated successfully with shotcrete, rockbolts and cable dowels. To minimize support effort and interference with mine production, early identification and treatment of unstable areas is important.

Jan 1, 1987

By Richard H. Lindgren

I appreciate this opportunity to discuss with you OPIC&apos;s new policies designed to assist U.S. minerals companies in developing new sources of minerals overseas. A comparison of recent figures on U.S. investment in mineral exploration, development and production gives results which are remarkable --and disturbing. Through the 1960&apos;s the flow of U.S. foreign direct investment in mining and smelting in the developed and less developed countries were nearly equal. However, by 1973, roughly 80% of all exploration expenditures by mining companies was taking place in the developed countries and principally in the U.S., Canada and Australia. Clearly it is to the interests of both the developing countries and the United States to put these figures back in better balance. As you may be aware, the administration as a whole is examining systematically what can be done by government to reduce the disincentives and increase the incentives to mineral investment in the less developed countries --the LDCs. A subgroup of the National Advisory Council chaired by the Treasury Department has been formed to coordinate U. S. Government policy and program efforts relating to mineral and energy development in these countries. Among other matters, this subgroup will examine how public policies could positively influence the private investment decision-making process in the minerals industry.

Jan 1, 1978

By Joseph T. Duncan, Syd Peng, Larry G. Stolarczyk

The mining business has numerous risks: equipment availability, labor disruptions, foreign exchange rate, etc., but one of the more important risks is assessing the geology. Improving the “intelligence” of geology can and will have significant positive effect on reducing mining risk and thus enhancing operational and financial performance. The use of the advanced Radio Imaging Method (RIM-IV) on coal seams and ore bodies can create useful two-dimensional (2-D) and three-dimensional (3-D) high-resolution images that provide mining engineers with additional intelligence to better plan and improve operations. Improved operational performance will reduce costs and enable mining companies to meet market and financial commitments. For the past decade the underground coal mining industry has been moving toward “super panels” in long-wall mining, and “super sections” for room-and-pillar mining. These mining conventions employ wider faces, longer gate roads, greater room-and-pillar density, and an increased scale in the amount and complexity of mining equipment. An obvious economy of scale exists: amortization of setup investments over greater volume of coal enables mine management to reduce fixed cost per ton. Restricted by equipment considerations, face widths have currently reached about 1,100 ft. Wider longwall panels are planned, with 1,400-ft widths, but this requires an incremental step in hardware that the original equipment manufacturers will soon bring to market. However, longwall panel length has not yet reached its limits, with some panels planned up to 25,000 ft. While longwall panel length is generally dictated by reserve size and extent, practical restrictions in mine planning also include seam thickness, ventilation requirements, or restrictions involving methane drainage. Super panels have certainly enabled the industry to keep pushing the limits of productivity improvement. However, important considerations in mine planning, now and especially in the future, will be driven in large part by geological factors. While larger developments improve productivity and capture economies of scale, the fact that super panels can contain at least four times the area or coal volume means that the probability of encountering serious anomalies is at least four times greater than with the “conventional” panels. Given the increased probability of encountering anomalies, improved assessment of geology is important for super panels and super sections. Proper due diligence requires a thorough and competent evaluation of a mining property and its ore reserve. Using improved geostatistical techniques is most important, and improving the base data for the analysis is equally important. The old cliché “garbage in, garbage out” certainly applies. Also, the quality of coal reserves is (or has been) declining, so, in the future, mining will be in deeper and most likely thinner seams—and these seams appear to contain greater anomalies that threaten efficient operations. To counter the impact of reserve deterioration, the industry is moving toward greater use of geophysical tools and services. Fortunately, tools such as the Radio Imaging Method™ (RIM-IV) system have been improved and can provide the industry with enhanced 2-D and 3-D images of coal seams and ore bodies. To identify and profile the best areas of a coal reserve, geologists, engineers, and mine managers need greater intelligence in the form of RIM-IV tomographic maps of longwall panels and room-and-pillar sections. These images have enhanced the understanding of in-seam features, which in turn has improved operational plans and performance.

Jan 1, 2005