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By P. M. Pettit

Hydrologic investigations at Gold Quarry began in 1989 and continued through 1991. Hydro-stratigraphic units include Tertiary sedimentary rocks, Paleozoic siltstones and carbonates. These units display complex and variable aquifer parameters as a function of faulting and hydrothermal alteration, creating compartmentalized hydrologic domains. Testing has included step-tests, spinner production logs and constant discharge tests. Two Three-Dimensional Finite Element Models have been developed, one for optimizing the pit dewatering system and the second for predicting regional impacts of dewatering. Aquifer testing and long term pumping have been used to calibrate both Finite Element Models.

Jan 1, 1992

By J. E. Lema

America's bulk commodity transportation systems have taken on a new look in the 1970's and 1980's. Railroad systems, barge lines providing inland and intra- coastal waterway transportation, and Great Lakes carriers have undergone substantial changes through mergers and acquisitions, consolidations of ownership and control, and construction of modern intermodal transportation facilities linking railroads and water carriers. The new look has generated some concerns and opportunities with regard to producers and shippers of bulk commodities which are characterized by the necessity of moving large quantities of heavy materials long distances. Clearly such transportation requirements call for efficient railroad and water carrier services. Shippers of commodities like coal, grain, .chemicals, minerals, ores, forest products, petroleum products, and heavy manufactured goods find reductions in transportation competition lead to concerns that rates charged by carriers will not be sufficiently constrained by market forces. At the same time, new policies on contracting for railroad services can lead to greater efficiencies, a rewarding opportunity for carriers which should be shared with shippers and consumers of bulk commodities. Then, of course, there's a related problem that in the absence of effective competition, the benefits of increased carrier efficiency will not be passed on, in part, to shippers and consumers, causing losses in markets for producers.

Jan 1, 1986

By Monserrat Rebolledo, John L. Uhrie, Candice Simms

Jetti Resources has developed a catalyst which overcomes the passivation of primary sulfides, enhancing the heap leach recovery of copper from chalcopyrite. It is important to emphasize that heap leaching of copper sulfides, whether with or without the Jetti catalyst, is a biooxidative process. We have demonstrated the efficacy of Jetti’s technology in bioreactors, with a chalcopyrite-dominant porphyry ore. In the presence of Jetti’s technology, optimal bioleaching conditions significantly increase copper extraction by 2.6 times that of the baseline.

Feb 1, 2025

By Douglas B. Silver

Study Parameters (Status as of February 1993) Time Period: 1989 -1991 151 North American Public Metal Mining Companies Fiscal not calendar year basis 85+% of Canadian and U.S. Metal Production Au, Ag, Cu, Pb, Zn, Mo, Ni, W Results are Preliminary and Research Continues Chicken Little is Alive and Well

Jan 1, 1993

Mining is big business in Ontario. The province is Canada?s leading mining region. It consistently ranks among the top 10 jurisdictions worldwide for exploration spending, reaching about C$1 billion in 2011. More than 26 percent of all exploration and appraisal dollars spent in Canada are invested in Ontario. Minerals produced include nickel, copper, platinum group elements (PGE), cobalt, zinc, diamonds, gold and silver. It was reported that there are more than 600 mining exploration projects in the province. And, recent discoveries of chromite in northern Ontario?s Ring of Fire will add to the province?s mineral production in the coming years.

Jan 1, 2013

By Tony Szwilski

A correlation between the rank, ash content and coal seam discontinuities and coal strength/stiffness is discussed. Rebound hammers were used to evaluate the strength properties of two coal seams. The coefficient of variability of the rebound tests are compared with those of laboratory compressive strength tests by other investigators.

Jan 1, 1985

By M. Manrique

Various pyrometallurgical methods for treating Ilmenite and Zircon concentrates are reviewed. Laboratory experiments, using a thermal plasma reactor, have been performed to evaluate: the conversion of ilmenite to TiC or TiC-Fe and the conversion of zircon to ZrC or ZrC-SiC. Results are examined and possible processing routes are identified.

Jan 1, 1996

By Ewan Wingate, Ranjit Prasad, Yanjun Liu

The phosphorus journey begins with the extraction of primary phosphorus in the form of phosphate in apatite through openpit mining and, in some rare cases, underground mining methods. The ores are processed in beneficiation plants to remove impurities before the phosphate rock concentrate is either sold on the open market or converted into phosphoric acid in downstream chemical production facilities by the wet acid process or thermal phosphorus routes. These can in turn be converted into fertilizers, as well as used in the food and electronic industries. The advent of the EV battery has given rise to a new use for purified phosphoric acid in the production of lithium ferro phosphorus (LFP) cathode material for EV battery cathode assemblies. The production of LFP relies on raw materials such as lithium carbonate, lithium hydroxides, iron salts and purified phosphoric acid.

Feb 1, 2024

The ability to increase and maintain dragline productivity is a key mine driver for the Coal Creek Mine. The Coal Creek Mine is owned by Arch Coal Inc subsidiary Thunder Basin Coal Company; located near Gillette, WY. Coal Creek Mine overburden stripping is primarily accomplished by a BE-1570W walking dragline in combination with cast blasting and dozer assist for bench preparation. The two main variables impacting dragline performance are maintenance reliability and operator skill levels. The mine?s most recent process improvement efforts have focused on its most valuable asset - the operator. Various techniques have been used to reduce variability in the dragline operator?s digging performance. Utilization and communication of operator performance data, statistics, and video reviews have been of great value towards achieving this goal. Operators are given a chance to critique operational tendencies from a third-person point of view, and are also presented statistical feedback to support observations. From these sessions, operators gain knowledge as to what portions of the dig cycle can be improved in order to reduce cycle time and increase productivity. BACKGROUND The BE-1570W walking dragline was commissioned at Coal Creek in November 2006 after relocating from Arch of Wyoming located in southeast Wyoming. The first two years of operation the machine was performing simple side cast stripping due to the low ratio. Coal Creek Mine is a multiple seam operation with overburden thickness ranging from 24 to 140 feet. Early in 2009 the ratio increased to the point where transitioning to cast blast/extended bench stripping was necessary. The current mining conditions consist of a mixture of both stripping styles where the ratio allows. The dragline crews running the machine consist of a mixture of experience levels ranging from 30+ years to only a few years. It has been in this digging environment and slightly inexperienced personnel that the focus has been set for improvement in dragline performance.

Jan 1, 2011

By J. F. T. Agapito

Two flat-lying trona seams 3-to 3.5-m thick, approximately 10 m apart, and at depths of 250 m are mined by room-and-pillar at OCI's Big Island Mine in Wyoming. Continuous miners and a yielding pillar system have contributed to improvements in resource recovery and productivity. Long-term stability with minimal subsidence is needed for a large portion of the mine beneath the Green River channel. This was investigated by computer modeling in 1990. Although results of the study indicated good long-term stability, recommendations were made for stress determinations to verify the model. Stress determinations made in 1997 showed pillar stresses 10% to 20% higher than the model stresses, and barrier pillar stresses 10% to 15% lower. This implies that higher panel stresses will be transmitted from the upper to the lower seam. A stability evaluation of the lower seam is planned before two-seam mining to assess entry widths and support requirements.

Jan 1, 1999

By V. R. Bovino

In the early 80's, the cover of a major weekly magazine proclaimed the "Death of Mining." A few years ago, mining conventions, similar to this, around the country sported the theme, "The Survival of Mining." Today, the SME announces that "Mining is Alive." Being part of an industry that is simply alive is not very exciting. We can do better! Our challenge must be to flourish, blossom, maximize our potential and expand our horizons. The pace of rejuvenating this industry is still woefully inadequate. The new generation of mining industry leaders recognizes the urgent need for bold operational changes?changes in the way we deal with our employees? changes in the way we achieve productivity? and changes in the way we reward our employees for productivity.

Jan 1, 1991

By III Westbrook

Although calcium sulfate dihydrate, commonly referred to as gypsum, has been utilized for some time in fiberglass reinforced polyester (FRP) applications, it does not have the fire retardant filler recognition of ATH. Gypsum is more commonly known for application in cement, soil and water treatment, plaster, and wall-board. Inherent characteristics of gypsum limit its use to low temperature and, until recently, non-aqueous applications. However, as a plentiful, naturally occurring hydrated mineral, the cost effectiveness of calcium sulfate dihydrate has prompted development and yielded success in the areas of FRP spray-up and latex carpet backing.

Jan 1, 1993

By Mahiyar Nasarwanji, Jonathan K. Hrica, Jonisha P. Pollard, Lydia M. Kocher, Brianna M. Eiter

Within the metal/nonmetal mining sector, fall-related incidents account for a large proportion of fatal and non-fatal injuries. However, the events and contributing factors leading up to these incidents have not been fully investigated. To help provide a clearer picture of these factors, an analysis of imminent danger orders issued by the Mine Safety and Health Administration (MSHA) between 2010 and 2017 at both surface and underground metal/nonmetal mine sites revealed that most orders are associated with fall risks. Of these cases, 84% involved the workers not using fall protection, fall protection not being provided, or the improper use of fall protection. Fall risks for workers most frequently occurred when standing on mobile equipment, performing maintenance and repairs on plant equipment, or working near highwalls. In most cases, a single, basic, corrective action (e.g., using fall protection) would have allowed workers to perform the task safely. Overall, these findings suggest that a systematic approach is needed to identify, eliminate, and prevent imminent danger situations. Furthermore, to protect mineworkers from falls from height, frequently performed tasks requiring fall protection should be redesigned to eliminate the reliance on personal fall protection.

By Walid M. Abdellah, Soliman Abu Elatta A. Mahmoud, Hanaa A. Abu Khoziem

The high-grade Th-U-Y zone is one of the numerous mineralized zones found in the El Garra El Hamra hydrothermally altered syenites in southwestern Egypt. It is characterized by the thorium minerals thorite and thorogummite, which are closely associated with xenotime-(Y). This zone of mineralization is localized in the eastern part of the El Garra El Hamra hydrothermally altered syenites. This zone does not relate to the first phase of syenites that appeared on the surface but is linked to the other, hidden phase of the syenitic body. Additionally, the fluids responsible for the mineralization of this zone belong to the late-stage hydrothermal event as well as the fault action due to the fact that it had continued reactivations for a long period of time. The studied mineralized zone also contains ceriopyrochlore-(Ce),(Ce,Ca,)2 (Nb,Ta)2O6 (OH), fluorite (CaF2) and barite (BaSO4), which are found in considerable amounts, whereas apatite (Ca5(PO4)3F) and chromite (FeCr2O4) are rarely found together with Fe-oxi-hydroxides (hematite and goethite) with a minor amount of jarosite (KFe33+(OH)6(SO4)2). Finally, the main constituent mineral in the zone is the pseudomorph perthite in addition to quartz, which is found as deformed crystals. A technological sample was collected from this zone and was found to assay 4.62 weight percent thorium (Th), 0.37 weight percent uranium (U) and 3.12 weight percent rare earth elements (REEs). From the chemical and mineralogical composition of the studied technological sample, the leachabilities of Th, U and REEs were investigated using sulfuric acid (H2SO4) agitation leaching and pug leaching methods. The latter was found to be preferred under the conditions of 0.54 ton H2SO4 per ton of altered syenite at 110 °C for two hours.

By Biswajit Samanta, Pranjal Pathak

This article presents a customized genetic algorithms (GA) with new crossover and mutation operators to solve the short-term production scheduling problem of multi-mine mineral value chains (MVC). The preceding problem consists of determining the extraction sequence and destination allocation of blocks from all the mines collaboratively while closely meeting the quality and quantity requirements of the processing units subject to relevant technical and operational constraints. The short-term production scheduling is carried out at shorter scales wherein the operations are modeled in a great detail with large number of constraints. This makes the industry-scale instances of the problem computationally intractable for standard mixed-integer programming (MIP) solvers. Thus, a GA-based heuristic approach is developed to obtain nearoptimal solutions to the large-scale instances of the problem in a reasonable amount of computational time. Computational experiments show that the developed GA-based method is a promising way to handle industry-scale instances of the problem. Moreover, the sensitivity analysis on various parameter combinations of crossover and mutation operators indicates that the customized global mutation operator, when used in combination with the customized crossover operators, took on average 12.5% less time than the customized local mutation operator to converge to a solution.

May 21, 2022

By T. D. Kaufmann

When Dr. David Gully solicited this paper last spring a few questions basic to commodity trade between the U.S. and world markets appeared perplexing. Why, for example, when the demand for aluminum was at a peak and when little expansion of capacity had taken place, was the dollar price half of what it had been at the previous peak? Or, why in 1984 when imports surged by 50% as the U.S. economy pulled out of its recession did the dollar not fall, but rather rose by 35%? And, why when the experts all seemed to agree that the dollar was grossly overvalued did the price of gold continue to decline? Surely these were extraordinary times for the mineral economist. When this paper was written in late July, 1985 the answers seemed clearer. The prices of many commodities were not low - the dollar in which they were denominated was too high. In other currencies many commodity prices were indeed high. The dollar was overvalued in trade terms by some 40% caused by an influx of short term coupon investments made by foreign money managers to take advantage of the higher short term interest rates in the U.S. relative to other international banking centers. With a decline in the relative difference in interest rates, an unhealthy buildup of foreign bank accounts and a perception that the dollar would fall, the dollar did start to decline rapidly.

Jan 1, 1985

By G. A. Irdi

An automated method of microscopy for determining the pyrite size distribution on two base coals that were crushed to 28 mesh x 0 has been developed. Polished epoxy-bound coal pellets were prepared and examined by a Zeiss IBAS image analyzer utilizing a program developed from provided software. Pyrite size distribution determination is considered a necessary first step in pyrite characterization that could lead to successful predictions, by microscopy, of a coal's theoretical pyritic sulfur removal. Our research efforts to date have indicated that the IBP-S can be a reliable instrument for determining pyrite size distribution in crushed coal. A program was also developed to convert pyrite size data to a weight basis for comparisons to the results from chemical analyses. The problems encountered in our research and their solutions will be presented in the discussion.

Jan 1, 1986

By Alden B. Carpenter

Brines (a solution containing more than 100,000 mg/l dissolved solids) in sedimentary basins are genetically related to evaporites in one of three ways: (1) dissolution of evaporite minerals, generally halite; (2) interstitial fluids in evaporites which are expelled from their source rock during compaction; (3) incongruent alteration of hydrous evaporite minerals (carnallite). Most brines of commercial interest originate as interstitial fluids in halite-rich rocks. These fluids are initially rich in magnesium, sulfate, and potassium but evolve in composition to an Na-Ca-Cl brine during their migration to their present host rock. A particularly important reaction in this process is: 2CaCO3 + Mgt+ = CaMg(CO3)2 + Cat (1a) This reaction reduces the magnesium content of the brine and ultimately converts it to a calcium-rich brine. The loss of sulfate occurs by two mechanisms. One of these is by direct precipitation as calcium sulfate (either as gypsum or anhydrite): Ca 2+ + SO4 2- = CaSO4 (2a) Additional sulfate may be lost from the brine by sulfate reduction: S042 + 1.33CH2 + 214- = H2S + 1.33CO2 + 1.33H20 (3a) The loss of carbonate species occurs by precipitation as carbonates: H2O + C02 + Cat = CaCO3 + 2H+ (4a) The net result of reactions 3 and 4 is: Ca 2+ + SO4 2- + 1.33CH2 = H2S + CaCO3 + 0.33H2O + 0.33CO2 (5a) The loss of potassium from brines is caused by the formation of potassium aluminosilicates: 2K+ + Al2Si2O5 (OH)4 + 4SiO2 = 2H + 2KAlSi2O8 + H2O (6a) The hydrogen ions produced by this reaction dissolve carbonates: 2H+ + CaCO3 = Ca 2+ + CO2 + H2O (7a) The net result of reactions 6 and 7 is: 2K+ + CaCO3 + Al2Si205 OH)4 + 4SiO2 = Ca2 + 2KA1Si3O8 + H2O + C02 (8a) A study of brines from central Mississippi has shown that the composition of these brines is related to the interaction of pore fluids from evaporites with minerals in the enclosing sedimentary rocks.

Jan 1, 1978

By R. K. Will

Granite Construction Company operates a rock quarry in the rugged Santa Cruz Mountains of central California indicated in Figure 1. Open pit methods are used to mine decomposed granite which is processed to produce sand, gravel, decorative rock and asphalt. The quarry is located near the village of Felton about five miles inland from the coast of the Pacific Ocean, and is near the campus of the University of California at Santa Cruz and several California State Parks. The area is heavily forested and is considered by residents to be environmentally sensitive. Because of the scenic beauty of the area and proximity to the San Francisco Bay area, a project such as a quarry receives the attention of regional residents and environmental organizations.

Jan 1, 1994

By Louis P. Gignac

The Lac Shortt gold deposit is located in Northwestern Quebec, at some 115 km west of the Opemiska Division and 380 km northeast of the Lac Dufault Division, as shown on Figure 1. Falconbridge's exploration crews drilled the first six holes in the gold-bearing ore zone in 1979. After further diamond drilling from surface in 1980, the decision was taken to carry out an underground exploration program. A three-compartment shaft was sunk to a depth of 340 metres in 1981 and 1982; it was followed by an extensive exploration program, which included 1073 metres of cross-cutting and footwall drifting, 645 metres of ore drifting and 11 200 metres of diamond drilling. The underground work was completed by mid-winter 1983. It was followed by a complete feasibility study of the Lac Shortt Project. After some $Can 14.2 millions in exploration expenditures, the Board of Directors of Corp. Falconbridge Copper approved in July 1983 additional expenditures of $Can 45 millions to bring the Lac Shortt Mine in production at the capacity of 261 000 tonnes per year. Gold price was $US 425 per ounce at the time.

Jan 1, 1985