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By T. Yegulalp, R. Farrauto, A. Belova, M. Castaldi

Calcium oxide, with its ability to capture and store carbon dioxide, is emerging to become an important tool in carbon management. Calcium oxide can be used reversibly to capture carbon dioxide in situ and then be regenerated to produce a pure stream of carbon dioxide ready for sequestration; the Zero Emission Coal Alliance technology utilizes this property of calcium oxide to generate emissions-free electric power from coal. The reaction of calcium oxide with carbon dioxide resulting in thermodynamically stable carbonate is well understood; however, the efficiency of this reaction is limited by the diffusion of gases through bulk calcium oxide and through a layer of carbonate formed on the surface. In addition, the regeneration of calcium oxide is an endothermic reaction and is favored at high temperatures. The purpose of this paper is twofold: first, to address the diffusion limitation, a thin layer of calcium oxide, supported on a high surface area material, is studied thermogravimetrically to demonstrate the physical adsorption of carbon dioxide on calcium oxide. The adsorption is to take place at temperatures lower than required to form calcium carbonate.

Jan 1, 2007

More than 1,200 professionals from the global tunneling and underground space industries are expected to be on hand for the 2009 Rapid Excavation and Tunneling Conference to be held at Caesars Palace in Las Vegas, NV. The conference, set for June 14-17, is sponsored by the Society for Mining, Metallurgy, & Exploration, Inc. (SME) and the Construction Institute of the American Society of Civil Engineers. The four-day conference will feature more than 100 technical papers in 19 sessions. Two one-day short courses are also planned, as are a pair of field trips. And the show?s exhibit will feature more than 120 of the industry?s leading equipment and service suppliers.

Jan 1, 2009

Mineral Resource Technologies(MRT) and Michigan Technological University (MTU)finalized an agreement that permits MRT to offer an advanced carbon removal technology process for coal fly ash from an ash residue generated by utilities. The agreement encompasses the dominant existing US patents using a wet process for fly ash enhancement. The wet process for coal beneficiation of a fly ash product involves four steps. First, a slurry mixture is formed of a fly ash material and a liquid. Second, gravity is used to separate and collect a first-material fraction of the fly ash, having a density less than the liquid. This is done by skimming off the flotation slurry material.

Jan 1, 1996

By John H. Bassarear

Large scale equipment can reduce both capital and operating costs for concentrators. Large semiautogenous mills can be effectively utilized in big mills but they must be kept fully loaded to take advantage of their great potential. With varying hardness ores, controlling throughput is difficult and careful design must take this into consideration. A variable speed drive on large primary semi- autogenous mills can overcome this problem to a considerable degree. This paper provides a base case using standard accepted technology of two wound rotor single speed 4,476 kW (6,000 hp) motors to drive the primary SAG mills of a hypothetical 36,364 mtpd (40,000 stpd) typical porphyry copper mill. One other fixed speed drive will be described and five variable speed drive configurations will be reviewed. Capital costs for the entire grinding circuit, from crusher product to flotation feed, were developed for the base case and each of the alternatives. A technical evaluation comparing the advantages and disadvantages of each drive is presented.

Jan 1, 1985

By MAHESH SHRIWAS, CHRISTOPHER PRITCHARD

Ventilation monitoring and control in mines are becoming an integral part of day-to-day activity for maintaining health and safety of miners. The authors evaluate potential real-time monitoring solutions for detecting and reducing diesel particulatematter, mine fires, and dust in situ, and examined the state-of-the-art use of ventilation monitoring and control in underground mines for detecting and reducing air contaminants to acceptable regulatory limit. Authors review relevant documents, including research papers, trade publications, and manufacturers’ website-based information, to identify research gaps. The authors also evaluate contemporary sensors (airflow, gas, dust, silica), control system and software technologies, data transport systems, Industrial Internet of Things, ventilation network simulators, and control devices to identify potential health and safety research gaps. In this study, examples of some mines from Canada, Australia, and the USA are included where ventilation monitoring and controls have been applied. Overall, this review identifies multiple challenges and research gaps in applying mine monitoring and control systems that could be the focus of future research, offering potential improvements to miner safety and health and financial benefits.

May 12, 2020

By Robert E. Kirby

The potash mine and refinery of AMAX Chemical Corporation is located 26 miles east of Carlsbad on the north end of the potash producing areas. This property was developed between 1949-1952 and production of muriate began in August 1952. Two shafts, located 400 feet apart, were sunk to the ore zone 900 feet below the surface. A 15-foot diameter ore hoisting shaft equipped with a 1000-ton ore pocket, crusher and automatic skip loading equipment plus a 20-foot diameter service shaft with a curtain wall for exhausting air were provided. Sylvinite production to date has been from the first ore zone, stratigraphically, the lowest of ten identified mineralized zones in the salt section. This first ore zone has been the top producer of Muriate of Potash over the years. In our area we do have some very marginal mineralization in the third ore zone some 35 feet above the first. We have not mined from this seam as yet but we are investigating the economics very closely with access slopes and an experimental mining panel. Our ore seam is generally flat lying but does have local gentle rolling with grades from 2% to 5%. The mine was designed and developed from the beginning with conventional mining practices and rail haulage from the mining section to the ore pocket. As mining progressed in the early years, production increased from less than one million tons annually to a maximum of 3,935,000 tons in 1964. Efficiency also kept pace with the increasing production and continually improved until the efficiency of the production crews reached an average of 100.3 tons per manshift in 1964.

Jan 1, 1974

By A. L. Slaughter

A mineral deposit has been discovered and explored sufficiently to establish the presence of ore in ?commercially marketable quantities," This is the point at which exploration ends and development begins, Of course, when the presence of commercially marketable quantities of ore are thought to be present the deposit had to be evaluated before this decision could be reached. If, on the other hand, it was thought that commercially marketable quantities of ore are not present, either more exploration has to be done or the project must be abandoned. It is this decision with which this paper is concerned, more particularly, the influencing factors behind this decision. The final question to be answered is: what profit can my company reasonably expect to make by developing this property and putting it into production? The answer must be expressed as a figure for final profit per ton, money which can be used to pay dividends or to build up cash reserves. Some acquisition cost has probably been paid and the exploration cost incurred at the time of decision, (abandonment or development). In addition to returning these acquisition and exploration costs, the deposit must pay development, mining, milling, capital expense of new plants and equipment, taxes, and various other related costs.

Jan 1, 1958

By G. W. Cutting

Interlocking material balances on complex mineral dressing plants greatly assist in metallurgical investigations: indeed, without such a balance, there is no firm basis upon which to base process performance evaluations. To achieve balances both qualitative and quantitative data must be rationalised in conjunction with the process flowsheet. WSL has developed a range of programs to evaluate interlocking material balances. However, to obtain maximum benefit from the balances, answers of direct value at the process level must be provided: WSL has developed also a range of programs for this purpose. Practical examples are given, which illustrate the benefits obtained from process balances.

Jan 1, 1979

By R. E. McIvor, Brian Cornish, J. A. Finch, Yue Tan, Claude Gagnon

Fred C. Bond is recognized throughout the mineral processing world as the father of comminution equipment applied science and engineering. The Bond Work Index became a universal standard, and is the most widely used measurement tool for comminution energy consumption. This biography is the story of his lifetime of study, work experiences, experimentation, analyses and findings. His numerous published writings are reviewed. His legacy is one of comminution process engineering that will be used in perpetuity.

Feb 1, 2024

By J. Swanepoel, J. H. van Laar, J. C. Vosloo, W. A. Pelser

Deep-level underground mining costs in South Africa are continuously rising due to the increased depth at which gold is being mined, resulting in a rise in virgin rock temperature and an increase in cooling requirements. Therefore, mines must evaluate various ventilation and cooling optimisation projects required to be implemented throughout their life of mine (LOM). This study develops a method to identify and prioritise large capital expenditure (CAPEX) underground environmental improvement projects, to improve thermal comfort underground. The solution presents a ‘multi-criteria decision-making’ (MCDM) process, incorporating the ‘analytic hierarchy process’ (AHP) and the ‘technique for order performance by similarity to ideal solution’ (TOPSIS) into the method to provide for scientific decision-making. These projects are evaluated based on four criteria, namely project risk, the impact on the underground thermal comfort, cost, and implementation time. This study’s solution uses ventilation simulations to determine the impact of the projects on the underground environment. The identification and evaluation of an environmental improvement project to best suit the current economic climate, while improving underground conditions and decreasing the safety risk is an essential aspect of the solution developed in this study. The method was implemented on a mechanised deep-level underground mine and showed that surface refrigeration is the most suitable alternative, which was implemented at the case study mine as validation of the developed solution. The study proves that the MCDM method is an adequate solution to incorporate subjective criteria into the decision-making process, resulting in a scientific and structured approach to making significant and complex decisions.

Feb 17, 2023

By Jack E. Thompson

I have spent my entire life in the mining industry pursuing what I believed was an honorable profession that provided products that were critical for our social and economic well being. Now I am told that all of my efforts been for nothing and that I have been doing something morally wrong - mining. This view of the future is not one that the mining industry has to allow to unfold. A determining factor in how things will turn out is continued improvement of the industry's environmental performance. To some extent, the current state of affairs in the United States is a result of the common perception that greedy corporations (usually foreign) are somehow ripping off US citizens of their native birthright or natural treasures in the name of corporate profits. Implicit in this view is the belief that corporations will take shortcuts or violate the environment in the name of profits. I have 26 years of experience in working in the copper, uranium and gold industries. Profits during those years were meager and difficult to find (Fig. 1). In fact, when I began working fresh out of college, I chose copper, which was then selling at around $1/lb. By the time I left copper mining, it was selling for 45 cents/lb. I then moved to uranium, which was selling for $52/lb. By the time I left it was $16/lb. I finally picked gold, which was then at ($650/oz). There is a whole generation of engineers, geologists and professionals who have spent two decades downsizing, closing mines, improving costs and getting smarter about how the mining industry does what it does. The environment, health and safety are areas where there have been great improvement. There are five characteristics of corporate governance that are critical for a company to develop and an industry to embrace if environmental, health and safety excellence is to reach new heights in the labor pool.

Jan 1, 1997

By G. Mike Bernard

The Andacollo gold mine is located near the town of Andacollo (population 14,000 people) in Chile’s region four. It is about 56km (35 miles) by paved road from the coastal city of La Serena. Santiago is about480 km (300 miles) south. Site elevation varies between 1,000 and 1,280 m(3,300 and 4,200 ft). The climate at the Andacollo site is moderate but arid. Average annual rainfall is only 130mm (5 in.). Because there is little rain and the temperature varies only a few degrees (14 to 24 C or 57 to 75F), there are no problems with freezing, solution dilution or pad saturation. The climatic conditions are ideal for heap leaching.

Jan 1, 1996

By E. Petrakis, K. Komnitsas

The main objective of batch grinding modeling is the estimation of the product particle size distribution over time or specific energy input to the mill. So far, the developed analytical methods require often complicated calculations which are timeconsuming. Thus, more simple approaches that allow the reliable prediction of the complete product size distribution need to be developed. In the present paper, an approach, based on the population balance model (PBM), that reliably predicts the product size distribution is proposed. In order to enable this, the simplified form of the fundamental batch grinding equation was transformed into the well-known Rosin–Rammler (R-R) distribution, thus allowing the determination of the breakage rate for each grinding period. A time-dependent breakage rate framework was developed where the traditional linear theory of the PBM is considered a partial case. This approach allows the deviations from the linear theory to be categorized and the degree of the acceleration-deceleration of the breakage rate to be predicted. Modeling results were validated by laboratory grinding studies using two homogeneous materials, quartz and marble, and one heterogeneous, a limonitic laterite. The experimental data revealed that grinding exhibits non-first-order behavior and the degree of deviation from the linear theory depends on the tested material. The reliability of the proposed model was validated with the use of the distribution modulus n, the a value of the breakage rate parameter, and the optimum n values that minimize the sum of the differences between the experimental and estimated particle size distributions.

Feb 8, 2021

By S. P. Sandoval

In 2002 the Freeport-McMoRan Technology Center undertook research to develop a lower-cost alternative to guar for cathode smoothing in copper electrowinning. The work was conducted at the Technology Center?s SXEW Test Facility located in Morenci, Arizona. Bench-scale copper electrowinning cells were designed and implemented to screen a number of potential polymers for cathode smoothing. These included modified polysaccharide polymers that were nonionic, cationic, and anionic in nature.

Jan 1, 2010

By Taghi Sharizadeh, MAURICE SUNKPAL, ELAHEH TALEBI, PEDRAM ROGHANCHI

Excessive heat exposure is among the health and safety hazards that have adverse effects on the mine workers. The very nature of the underground climate makes it a convenient avenue for heat generation and accumulation from several heat sources including autocompression, equipment, and heat from strata. This study investigated the effects of clothing insulation and acclimation on the thermal comfort ofmineworkers who are exposed to heat in underground working environments. Several clothing ensembles have been considered to analyze the effect of the thermal resistance of clothing on the thermal comfort of workers. To investigate the impact of the clothing insulation, the thermal comfort limit of an underground miner was calculated in the form of maximum allowable exposure time for an 8-h shift. Parametric analyses were subsequently performed using an already developed thermal comfort model using MATLAB software. The results demonstrate that clothing insulation has a significant effect on the thermal comfort of mine workers. Increase in the clothing insulation decreases the maximum allowable exposure time of mine workers. This is especially true for the new and non-acclimated workers. Since acclimatized workers can tolerate a higher level of the dehydration and are capable of losing more water by sweat per shift, the maximum allowable exposure time for the acclimated workers are higher than non-acclimated workers. These analyses have shown that acclimated workers can have more continuous work per shift compared with non-acclimated workers. For example, in an environmental condition with clothing that a nonacclimated worker cannot work more than 5 h, an acclimated worker can work a full 8-h shift.

Jun 29, 2020

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 A. K. Gangopadhyay

This paper discusses the effect of grinding media composition, mineral type and slurry environment on the wear rate of various grinding media (balls). Sufficient wear data have been obtained and correlated with the modes of wear determined from examination of the ball surfaces using scanning electron microscopy. Five modes of wear have been identified to be operative under certain slurry conditions for the various ball compositions studied.

Jan 1, 1984

By W. Clark Ashby

Productivity is a fascinating concept. Like motherhood or apple pie, we know it as a good thing. Just what it means is not so clear. To a coal miner we assume it means tons of coal hauled from the mine. To the company president it means profit after capital, labor, and other costs have also been reckoned. To the government economist it means output in a balance of payments. What does it mean to the biologist, and can reclamation really be productive? In this paper we discuss productivity from a biological viewpoint, give some yield data for various types of reclamation plantings, and discuss how our demand for or acceptance of differing kinds of productivity is tied up in bigger questions of land use, environmental stability, and resource allocation.

Jan 1, 1981

ME?s Arizona Conference was held at the Hilton El Conquistador resort in Tucson on Dec. 2 and 3, 2007. The annual conference is organized by the Arizona Conference Board of Directors, which represents SME sections in Arizona and adjacent areas. The conference provides an opportunity for individuals and corporations associated with mining in the region to get together once each year to discuss the status of the industry. The 2007 meeting featured a keynote address, a distinguished lecturer and more than 25 technical papers that were presented in seven sessions. The sessions included environmental, geology, safety, metallurgy, mining, new projects and a special session on Mexico. Topics covered included mine closure, sustainable mining, exploration methods, health and safety issues, mining equipment and drilling. Much of the discussion at the conference concerned major new developments in the region?s copper mining industry. For example, Freeport-McMoRan?s new Safford Mine and BHP Billiton?s Pinto Valley restart were the topics of technical presentations. There was also much discussion among the attendees on the current and future price of copper, community relations, education issues and recruitment concerns. At the time of the conference, the price of copper hovered around $3.30/lb, up considerably from the 61 cents/lb in late 2001, when the industry was being challenged by world market conditions and a weakened domestic economy. Since then, strong demand from China helped push copper prices to record levels that at one time reached as high as $4/lb. The general consensus among the attendees is that the current price of around $3.30/lb will continue through 2008. Most attendees also expect increased corporate investments in the industry to continue. Copper mining in Arizona has been a major industry since the 1800s. In 2007, Arizona was the leading copper-producing state in the United States and produced more than $5 billion worth of copper. The copper mining industry in Arizona also produces byproduct gold, silver and molybdenum. Arizona is the second largest molybdenum producer in the United States.

Jan 1, 2008

By Shuie Li, Taibai Li, Tao Hu, Zhongjie Wang, Xiang Ge

As one of the main power sources, lithium-ion batteries (LIBs) will continue to be applied on a large scale in the future market. Commercialized LIBs cathode materials contain various valuable metal elements including Li, Co, and Ni. The development of green and efficient recycling technology is essential. Deep eutectic solvents (DESs) have recently emerged as a new class of green solvents that could potentially be applied for the LIBs recycling industry due to their capability to leach the active materials without the introduction of environmentally hazardous reagents as used in conventional hydrometallurgy process. Considering the rapid progress, a critical review focusing on the progress and fundamentals about the overall efficiency has practical significance for the further advancement of this field. Herein, we briefly introduce the overall process of using DESs for LIBs recycling and specifically focus on the efficiency of each step. Current fundamental understandings and new experimental approaches to enhance the efficiency of the leaching process, the extraction process, and reusability are summarized. We expect this review article to inspire scientists to use DESs as powerful tools for advancing the frontiers of LIBs recycling.

Jul 30, 2022