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By Y. Guan

The dissolution behavior of copper and gold from their pure state and from Au/Cu alloys in cyanide solutions has been investigated using a rotating disc. Oxygen was used as an oxidant. The effect of the composition of the alloys, stirring speed of the disc, concentration of lixiviants and temperature on the overall dissolution kinetics has been studied. Gold/copper alloys of three compositions were used in this study. The atomic percent of gold in these alloys was 75, 50 and 25, respectively. The dissolution behavior of these three alloys was compared with that of pure gold and of copper under the same chemical conditions. In general, the dissolution of copper and gold from alloys is partially controlled by surface chemical reaction and largely by mass transfer.

Jan 1, 1992

By C. A. Born

AMAX Inc. climax's mine-mill complex at Climax, Colorado is best known for its molybdenite production: 50,000 TPY of molybdenite flotation concentrate (95% MoS2) from mill heads containing 0.35% molybdenite. Less recognized are the byproducts that are concentrated from the tails generated in the rougher flotation circuit (see Figure 1). Climax recovers a heavy mineral concentrate by passing the rougher tailings from molybdenite flotation over Humphrey spirals (Figure 2a). This concentrate is floated using xanthate at pH 4 to remove sulfides, principally pyrite. The tails from the pyrite float are then cleaned of quartz, feldspar and light minerals by tabling (Figure 2b). Amine flotation follows at pH 1.5 and 75°C to float monazite (Figure 2c). The present circuit at Climax dries the monazite flotation tailings and utilizes high intensity cross-belt magnetic separation Figure 2d) to generate a high grade wolframite concentrate and a low-grade cassiterite product, both of which are contaminated with the mineral brannerite, (UO, TiO, UO2)TiO3. The uranium specifications have recently become difficult to meet due to the increasing percentage of brannerite reporting in the mill feed. A plant is being built utilizing hot sulfuric acid and sodium chlorate to leach this uranium from the monazite flotation tailings prior to their being fed to the wolframite- cassiterite magnetic separators. This modification is the subject of our paper.

Jan 1, 1975

By Yuexin Han, Mu. Yufan, Yanjun Li, Peng Gao, Yongsheng Sun

"The objective of this study was to evaluate the effect of reduction temperature, reduction time and binary basicity on the size of metallic iron particles in coal-based reduction products of an oolitic iron ore. The particle size distribution behavior (i.e., cumulative passing percentage and mean size of metallic iron particles) during reduction was investigated in detail. Results showed that the particle size distribution of metallic iron particles was strongly influenced by reduction temperature, reduction time and binary basicity. The cumulative passing percentage and mean size significantly increased with reduction temperature and time in the entire range of the experiments. All curves of cumulative passing percentage versus particle size under different conditions demonstrated a similar trend (continuous increase). The size distribution parameters and mean size slightly increased with increasing binary basicity and significantly decreased when the binary basicity exceeded 1.0. The size of metallic iron particles could be controlled by adjusting the reduction conditions during coal-based reduction.IntroductionThe increasing demand for iron ore coupled with diminishing high-grade iron ore reserves has resulted in the urgent need for innovative technologies in order to use refractory iron ores. Oolitic iron ore is a typical refractory iron ore with tremendous abundance globally. Based on published literature, oolitic iron ore reserves are approximately 140 million tons in Europe, 10 billion tons in China and 66 million tons in Pakistan (Kazmi and Abbas, 2001; Wu et al., 2011; Yu and Qi, 2011; Sun et al., 2013a). Therefore, the efficient exploration and use of oolitic iron ore resources can play a significant role in easing the mineral resource crisis in the iron and steel industry. However, oolitic iron ore cannot be effectively upgraded by traditional beneficiation methods due to its mineralogical characteristics (e.g., low grade of iron, poor liberation of iron minerals and high phosphorus content) (Li et al., 2011b; Sun et al., 2013b).Researchers recently proposed coal-based reduction followed by magnetic separation to recover iron from refractory iron ores (especially oolitic iron ore) and a certain degree of breakthrough was achieved in both theory and practice. In this technology, iron minerals in the ore are directly reduced by coal to metallic iron, which grows into particles of different sizes. After comminution and liberation, metallic iron is concentrated by magnetic separation (Srivastava and Kawatra, 2009; Sun et al., 2013a; Li et al., 2011b; Sun et al., 2013b; Li et al., 2011c; Gao et al., 2013). Sun et al. and Gao et al. used this technology to examine the recovery of iron from oolitic and Bayan Obo iron ores, respectively (Sun et al., 2013a; Li et al., 2011b; Li et al., 2011c). Metallic iron powder with more than 90% iron content was obtained as the final product, which could be used directly in steel production."

Jan 1, 2015

By José Mujica, Mónica Campos, María Fe Campos

The extraction and processing of metals and other minerals have played an important role in economic, political and social development worldwide, from the early stages of prehistory to the present day (Gosner, 2020). Mining has been a fundamental part of human civilization, providing the raw materials necessary for technological, infrastructure and industrial advances. As society progresses, the importance of mining continues to grow, supporting the development of everything from the smallest electronic devices to the tallest skyscrapers (Escamilla, 2024). The economy of a nation is connected to its extractive industries (Moreira and McMahon, 2014), which have seen dramatic growth in recent years (Pietrobelli et al., 2018). In a context of increasing demand for natural resources, driven by the development of emerging technologies, the expansion of infrastructure and the foundation of engineering achievements for the coming decades (Minerals Education Coalition, 2024), mining should focus efforts on global development, requiring a comprehensive approach to sustainability that addresses the planet’s needs and protects the well-being, primarily, of the communities and environments where mining operations take place (Figari, 2024). In these areas, diversity and inclusion should be promoted, thus fostering equitable and sustainable development. The sustainable development goals (SDGs), also known as the global goals, could serve as a key framework for fostering a strong social management culture in mining. The SDGs were adopted by the United Nations (UN) in 2015 as a universal call to end poverty, protect the planet, and ensure that all people enjoy peace and prosperity by 2030 (United Nations Development Programme, n.d.). Companies have compelling reasons to align their actions with the SDGs, as their long-term success depends on healthy communities. This is a major challenge that requires collaborative efforts (Singh and Rahman, 2021). As Fraser (2021) mentions, achieving more sustainable outcomes may involve mining companies and communities working together collaboratively. This article proposes an innovative approach: Inclusive mining for sustainable development, which aims not only to maximize economic profitability but also to promote social and environmental well-being by integrating the UN’s SDGs, primar)ily focused on diversity and inclusion. This can be achieved through the implementation of a key value-added initiative for mining companies: the creation and operation of a corporate volunteering program aimed at developing and executing inclusive practices to promote gender equality, the inclusion of local communities and indigenous peoples, and accessibility for people with disabilities. This proposal will educate employees and stakeholders about sustainability and promote concrete actions through corporate volunteering to strengthen the mining company’s commitment to community development, improve social relations and advance toward achieving the UN’s SDGs, establishing the company as a global change agent.

Nov 1, 2025

By Yuexin Han, Yanjun Li, Peng Gao, Yongsheng Sun, Qiang Zhang

The non-isothermal magnetization roasting process and isothermal magnetization roasting process of siderite ore were investigated using thermogravimetric (TG) analysis and a real-time infrared gas analyzer. X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) were used to analyze the characteristics of samples. The results showed that the decomposition degree and decomposition rate of siderite ore were vitally affected by heating rate and roasting temperature. It was determined that A1 reaction model (f(α) = 1 − α) and A3/2 reaction model (f(α) = (3/2)(1 − α)[−ln(1 − α)]1/2) were the most probable mechanism function of the non-isothermal decomposition process and isothermal decomposition process, respectively. The phase transformation and decomposition mechanism during the roasting process were evaluated. Siderite decomposed in the process of magnetization roasting, released CO and CO2, and transformed into strongly magnetic magnetite. The SEM images highlighted that as the decomposition progressed, the structure of roasted samples was destroyed, and an increasing number of cracks and pores emerged on the surface, which is advantageous to the following grinding process.

Mar 26, 2021

By M. Stephen Enders

The Little Rocky Mountains host epithermal gold-silver bearing vein and stockwork deposits in a syenite intrusive complex. Pegasus Gold Ltd. is currently mining the oxidized deposits by open-pit methods and recovering gold and silver by heap-leach processes. A geologic program has been designed to effectively determine the basic ore characteristics; 1)mineralization; 2)oxidation; 3)structural setting; 4)lithology; 5)alteration; and ultimately, 6)the leachability of the ore. Geologic mapping, sampling, drilling, assaying, and testing are routinely used in exploration, development, production control, mine planning, and ore reserve estimations. Timely and accurate assay results are essential for the program's success.

Jan 1, 1983

By Fred Perea

The practical example of the effectiveness and necessity of establishing and maintaining close communications between the design engineering section and operating section of a large plant concerned with the building of an underground crusher will be presented.

Jan 1, 1969

By Robert D. Schmidt

The US Bureau of Mines is cooperating with Cyprus Mineral Park Mining Co., Columbia University, and the US Geological Survey in investigating the feasibility of applying in situ leach mining methods to fracture-hosted, supergene copper sulfide (chalcocite) ores. This paper presents the initial findings of mineralogical, hydrogeological, and geochemical characterization studies conducted at the Mineral Park mine, located in the Wallapai mining district of northern Arizona. A design for in situ leaching is proposed that would minimize the need for blasting prior to leaching, and would enable economical development of deep reserves at the Mineral Park mine. The in situ leaching design would also reduce the potential for long term acid rock drainage.

Jan 1, 1995

By Ted H. Eyde

Nearly 17 years ago a major producer of synthetic zeolites started an extensive exploration program for natural zeolite deposits which resulted in the discovery of over 170 occurrences in the western United States. A few years later several of the other producers and consumers of synthetic zeolites also started similar exploration programs. Since then, small quantities of natural zeolite minerals have been produced from at least 12 deposits in the United States. Of these the Bowie deposit, about 13 miles north of Bowie, Arizona, is the most important,having produced over 5,000 tons of vitric tuff zeolitically altered to the mineral chabazite and minor amounts of the minerals erionite and clinoptilolite. Mining Districts and Mineral Deposits of Arizona compiled by Charles A. Mardirosian, Consulting Geologist, estimates the value of the total production from the Bowie deposit at a very conservative $2,000,000. Unfortunately, none of the companies responsible for the discovery and the initial production of natural zeolites made any effort to develop the high volume, low cost applications of this unique mineral raw material. Instead, they developed only the high unit value uses to supplement their existing synthetic molecular sieve product lines. With the producers of synthetic zeolites thinking in pounds and not in tons, further development of natural zeolite deposits stagnated for over a decade.

Jan 1, 1974

By Kenneth P. Neumann

The development of the Cyprus Thompson Creek Molybdenum Deposit near Challis, Idaho, began in 1967 when the first mining claims were staked on the intrusive rock outcrop. Exploration drilling continued for the next 14 years. During 1978, a decision was made to develop the deposit. In December, 1980, approval of the Environmental Impact Statement was received and construction of facilities and waste rock removal began. By the middle of 1983, 126 M metric tons of rock had been removed and all facilities were completed. The high work ethic of Cyprus Thompson Creek employees combined with innovation has made the mine one of the most efficient in the United States today.

Jan 1, 1983

By F. A. Campbell

This paper reports on mineral facies, ore textures, distribution of iron in sphalerites, and fractionation of sulfur isotopes in the Anvil ore body, Yukon Territory, Canada. Because the detailed structure and stratigraphy, both regional and local, are being studied by the geological staff at the mine and members of the Geological Survey of Canada, these topics will be discussed only briefly. The results of our study of the Anvil ore body have implications on theories of the genesis of ore deposits of this type, and these will be discussed. The Anvil ore body is the largest and most significant of three lead-zinc discoveries in an area of the central Yukon where major lead-zinc deposits were unknown only twenty years ago. The Vangorda deposit consisting of 22 million tons was discovered in 1953, followed in 1954 by the Swim Lakes deposit consisting of 10 million tons. The Anvil deposit, which consists of three ore zones, was discovered in 1964. The total reserve at Anvil mine is 63.5 million tons, with an average grade of 3.4% lead, 5.7% zinc, 0.16% copper and 1.2 ounces of silver per ton. This study is concerned primarily with the number one ore body which is about 2,400 feet long, up to 1,100 feet wide and 300 feet thick.

Jan 1, 1973

By M. D. Johnson

The San Andres mine, located in the western mountain region of Honduras, Central America, contains epithermal gold mineralization as disseminations, in quartz-chalcedonic veins and stockworks. Host rocks include a thick sequence of Cretaceous to Tertiary conglomerates, sandstones, rhyodacite tuffs and andesites. Mineralization is controlled by northwest and northeast striking, normal faults and fractures which dip steeply east and west. Currently, 500 STPD of 1. 93 Grams/MT gold ore is being open-pit mined from the conglomerate and andesite. The mine is at the west end of a mineralized zone that can be traced over an area of approximately 1.5 square kilometers.

Jan 1, 1993

By Carolina Bruecker, Axel Preusse

"The topic of ground movements in Germany has been studied extensively in the past, especially in the field of active mines. The active hard coal mines were finally shut down in 2018 in Germany and lignite mining is expected to take place only until 2038. The so-called long-term liabilities of the mine operators in Germany include, among other things, the long-term guarantee of stability and thus the monitoring of ground motion.So far, the economic use of underground mining in Germany was mainly the supply of raw materials. In the future, the underground storage of compressed air, methane, or hydrogen will play an important role in renewable energy supply and climate change. Therefore, underground storage space will become more important and spatial planning is essential to ensure availability of safe underground openings for the various options of environmentally friendly energy storage.However, this renewed usage of underground openings may also bring new and sometimes unknown challenges of geomechanical influence. On the one hand, the aftermath of hard coal and lignite mining will be an increasing challenge in mining subsidence engineering. On the other hand, new possibilities due to underground spatial planning may lead to subsidence and/or heaving of the upper surface.INTRODUCTIONBoth hard coal and lignite have a long tradition in Germany. The Prosper Haniel mine in the Ruhr area was closed at the end of 2018 after 150 years, which signalled the end of hard coal production in Germany. Lignite mining still takes place in the Central German, Lausitz, and Rhineland districts. However, lignite mining in Germany is expected to be phased out gradually by 2038 (MDR, 2019). With the closure of these mines, however, mining damage is not over. The long-term consequences of mining, which extend far beyond the closure of the mines, are associated with the liability and responsibility of the individual mining companies. The so-called eternity burdens on the mining company continue to apply. In the field of lignite production, the discontinuation of dewatering and the resulting possible elevations of the surface will be a relevant topic for the future of mine surveying. The same applies to the hard coal mines, which are partially flooded in Germany and therefore require extensive monitoring of soil movements in the future.The discontinuation of energy from hard coal and lignite calls for a change in the energy mix. With the renewable energy revolution in Germany, the focus is on a sustainable and environmentally compatible climate and energy policy based on renewable energies. Sustainable use of the subsoil, both natural and anthropogenically produced cavities, will play an essential role in the objectives of this policy. For example, disused mine cavities can be used to store electricity from renewable energy sources. (Umwelt Bundesamt, 2018) These functions will again cause classical ground movements such as subsidence and uplift, but will also bring new challenges for the mine surveyor. Challenges can be underground cavity exploration in inaccessible areas or legal aspects of underground competition."

Jan 1, 2019

By X. Cai, L. Jiang, G. Fu

A process for recovering manganese from low-grade manganese oxide ore through a reduction acidolysis-selective leaching method is investigated. Two types of biomass, sawdust and straw, were used as reductants. Reduction acidolysis, using concentrated sulfuric acid, was used to disrupt the structure of the biomass, allowing the biomass to be hydrolyzed into monosaccharides. Analysis by X-ray diffraction revealed that Mn2O3 was reduced to MnSO4. Then, in the selective leaching process, iron was removed through the formation of goethite. The optimized experimental parameters are as follows: reductant to ore mass ratio of 0.4, sulfuric acid to ore mass ratio of 0.9, water to ore ratio of 0.5, aging time of 18 h, leaching temperature of 95 °C, leaching time of 90 min, and solution pH of 2.5 to 2.8. Under these conditions and using sawdust as the reductant, the manganese leaching efficiency and iron removal efficiency were 91.8 and 99.2 percent, respectively.

Controlled blasting experiments in small development drifts were conducted at CANMET's Experimental Mine, from August 1992 to November 1993. The objective of these experiments was to develop suitable controlled blasting techniques for small development headings drilled by jackleg with 32 mm diameter holes. The experimentation also aimed to provide insight into blast damage mechanisms. Particular attention was given to the physical-mechanical properties of the rock and the rockmass structural data in order to make the results applicable to other geological environments. The drift faces were approximately 2.4 m by 2.4 m with 36 to 43 holes drilled to a depth of 2.4 m. Cartridged water gels, emulsions and semigelatin dynamite were used in the cuts and as primers, ANFO as the main explosive and decoupled 19 mm diameter semigelatin dynamite charges were used in the perimeter holes. Smooth blasting techniques and pre-splitting were tested in the underground mine. All the blasts were monitored with a multi-channel blast vibration monitor to which was attached sets of high frequency geophones and accelerometers. This first set of experiments has illustrated the efficiency of con-trolled blasting techniques to reduce blast damage and demonstrated the need for further research to improve the safe and efficient use of explosives.

Jan 1, 1995

By Koichi Nishimura

Japan's coal reserves are estimated at 8,583 million tons (according to the materials on X World Energy Conference,. 1976). Japan is a long island country in the shape of an elongated cashew nut whose top is pointing to the north and its lower tip is pointing to the west. And her major coal fields are located in the two extreme far parts of Hokkaido in the north and Kyushu in the south. On the other hand, Japan's major industrial center are located in the central part of the country far from either coal-producing areas. This fact places coal a great geographical disadvantage in comparison with petroleum whose refining bases are concentrated on the coastal regions virtually next to major industrial centers.

Jan 1, 1982

By Dai Wang

Stoppings are necessary ventilation control devices for effective air distribution underground. However, one of the major problems underground mining has is that every stopping is a potential leaking source. Since air always flows from a point of high pressure to one of lower pressure, and the total pressure at every point in intake airways is higher than that in the return airways, air will always tend to leak from intake to return (Tien, 1996). In many mines, less than half of the air entering the mine actually gets to the working areas; the rest of it simply short-circuits directly to return airways through leaky stoppings instead (Timko and Thimons, 1983). Leakage through a stopping occurs because of pressure drops across the stopping and available leaky path in stoppings. Empirical equation has been widely used to characterize the relation the amount of leakage and variables that affect leakage. However the use of this equation requires accurate information for constants which are not always readily available. It is the attempt of this paper to derive an equation similar to the Atkinson Equation that can readily be applied to characterize pressure-leakage relationship for any given stopping.

Jan 1, 1998

By Francis X. Murray

Synthetic fuels will be the first major development effort to feel the effects of a new set of opposition forces. These confrontations will not be of the same variety as those which occured in the 1970s. Instead the synfuels industry, particularly in the West, will find itself confronting a new coalition of local political, community, and state spokesmen. They will oppose synfuels because the projects will represent a threat to existing lifestyles, political structures, taxes, social life, water rights, economics, and other politically sensitive considerations. In short, they mean change -- usually dynamic, full of unknowns and always threatening. The battles themselves may be fought technically over environmental issues, law and regulations; often these will be the instruments of the opposition. The real underlying problems will likely lie much deeper. In many cases environmental groups will be enlisted as the standard bearers; however, this approach may simply reflect the fact that environmental objections are convenient or at times the only tools at hand.

Jan 1, 1981

By Jerry Williams

GEORGE WEINMAN: At this time, our co-chair, Jamie Davis from Phelps Dodge, will come to the podium. JAMIE DAVIS: Our next speaker is Jerry Williams from Phelps Dodge, Morenci. Jerry is the maintenance planning supervisor and is in charge of preventative maintenance and maintenance scheduling. Jerry's group uses predictive tools to monitor and predict the equipment failure throughout the mine, from pumps to shovels to motors, you name it. The title of Jerry's talk is "If You're Not Using Predictive Tools, You're Behind the Curve." I’ll turn it over to Jerry.

Jan 1, 1998

By R. K. Mensah-Biney, M. T. Hepworth, K. J. Reid

The loading characteristics of gold-bromide species onto activated carbon were evaluated using a batch system. The overall loading of gold onto activated carbon was rapid for the first few hours, but it continued without cessation as a result of the reduction of gold. Therefore, conventional equilibrium considerations were not applicable. Although loading continued slowly after several days, an abnormally high, loading capacity value of 10-12 meq/g carbon (650-800 kg Au/t) could be attained in 72 hours. The loading of gold-bromo species by activated carbon was by the mass transfer of (AuBr4)- species to the external surface to be reduced to metallic gold by carbon. Elution of gold from loaded carbon was feasible provided the carbon had not been loaded to high capacity values. If loading is carried to high levels, complete elution becomes impractical, and the gold may be recovered by ashing the carbon. For the high loading capacities observed, this option would appear to be cost effective. The effect of several variables on the loading capacity of the activated carbon for gold-bromo species is discussed.

Jan 1, 1994