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"The National Mining Hall of Fame and Museum (NMHFM) announced the class of 2019 National Mining Hall of Fame inductees. This year’s inductees, selected by the National Mining Hall of Fame’s Board of Governors, represent exceptional financial acumen in assembling several operations that formed the basis of a successful American mining company; conception and development of equipment which contributed to improved efficiency and mine safety; and unrelenting advocacy for the U.S. mining industry and its workers. These individuals, selected for being determined, forward-thinking innovators, doers and leaders have propelled the industry toward vastly improved safety and social responsibility.The Prazen Living Legend of Mining Award, named for renowned mining artist Gary Prazen, will also be presented at the ceremony. This award recognizes an individual or organization for significant and sustained commitment to educating the public about the relationship of mining to our everyday lives through educational materials, programming, and outreach.2019 National Mining Hall of Fame inducteesFrank Calandra, Jr. has devoted more than 50 years to the mining industry and he is an icon in ground control technology for the mining, tunneling and civil construction industries.From the ground up, his passion, sweat equity and shrewd business acumen have grown Frank Calandra, Inc. (FCI) and Jennmar from a single plant in Pennsylvania to a world-class enterprise with 25 plants employing thousands globally. As evidenced by Calandra’s more than 20 patents on ground control devices (not to mention the additional 80 patents his companies hold), his innovation and commitment to safety have made underground mining safer and more efficient. In the late 1970s and early 1980s, Calandra was instrumental in upgrading American Society for Testing and Materials (ASTM) standards in roof control for both state and federal regulations. Through his work with industry associations such as the National Mining Association, National Coal Council and Center for Energy and Economic Development, among others, Calandra has contributed his time, expertise and financial support to ensure a balanced political and regulatory climate for mining. Calandra is an inductee of the West Virginia Coal Hall of Fame."

Aug 1, 2019

By W. G. Pariseau

Joints may be taken into account when using numerical modeling as an aid to mine design by embedding joints in the model. When using the popular finite element method, say UT3PC, a pre-analysis step is necessary, Step 0. This step is for the computation of equivalent properties of a representative elementary volume of jointed rock (REV) in the model. This Step 0 is taken before Steps 1, 2 and 3 for specification of a rock properties file, generation of the mesh, and model analysis are taken. A brief explanation of equivalent properties and several examples aid in explaining the details of Step 0. Focus is on procedures, input files, and output to show ease of computation. Theoretical details are relegated to references (e.g. Pariseau 2022). Comparisons of safety factor distributions about example mine excavations with direct scaling from mine observations then offer some insights concerning equivalent properties, especially strengths.

Feb 1, 2023

By S. M. Smouse

Total world energy consumption is projected to continue its strong growth of recent years. Because coal is the most abundant fossil fuel, it will likely remain an important energy source, particularly for power generation, into at least the early years of the next millennium. Clean coal technologies are available today that can economically reduce air pollution, primarily SO2 NOx and particulates, and for the higher efficiency technologies, CO2, from power generation. U.S. Department of Energy analyses show that the adoption of clean coal technologies could decrease carbon emissions worldwide while creating a strong export market with attendant creation of jobs in the U.S.

Jan 1, 1998

By A. H. Srnallbone

Over the past few years the rising production costs, shortage of skilled labor, and increased use of lower grade ore bodies have all added justification for the use of on-stream analysis. A rise in the number of on-stream units indicates that this type of assay is now being accepted as a necessity. On-stream analysis is a much more rapid means of obtaining true assays of a flowing product when compared to wet chemistry or "grab" samples dried, briquetted and assayed by x-ray. In contrast, on-stream analysis uses real time samples assayed every 30 seconds while each stream is assayed every 5 to 15 minutes. It is very important not only to know that a change has occurred in the process, but to know what caused the change and how to correct for the change. For example, in a tailing sample the elements of interest comprise between 1% and 10% of the sample. The remainder is water and gangue. Previously the gangue was not assayed nor were the low atomic number elements used for corrections. In addition to the demand for higher accuracies some concentrators were being penalized for excessive Ca or in some cases 5i in their concentrates. This penalty was being imposed by the smelter in order that they could better cope with pollution problems and prolong the life of their furnaces. But until Ca, 5i, and S are measured on-line, nothing can be done about their control. By accurately measuring these light elements on-line, a complete assay is obtained of the total sample providing improved accuracy for the important products. The justification for complete accuracy assays is now even more obvious because they are possible at very 1ittle increased cost and at no increase in analytical time.

Jan 1, 1977

By Sheridan A. Glen

As the Federal government along with individual states continue to grapple with the job of refining a comprehensive energy policy, coal continually stands out as an energy source which heralds a combination of old and new capabilities like an energy planners prophecy, but which is plagued with serious environmental constraints. To determine what level of coal utilization is ultimately possible for states East of the Mississippi, whose high sulfur content coal presents the most paramount of challenges, one must consider product availability, via existing transportation modes, the developing industrial markets and the ability of coal to meet the challenge of becoming an environmentally acceptable fuel. Gasification is emerging as a form of utilization, which during the next twenty years stands a good chance of being able to meet the challenge of making coal an environmentally clean, easily transport-able and usable fuel. It can be argued that, of all the potential ways of utilizing high sulfur coal, coal gasification is perhaps the most expensive, the most financially risky and carries environmental liabilities of its own. Synthetic gas and oil markets will undeniably be a function of price and demand, which, for the purposes of this paper, I'm assuming will begin to merge in the late 1980's and into the 1990's. This is also presuming that public utility commissions will allow favorable price structure ruling so that gasified coal products can be rolled into their respective rate base, much the same as synthetic natural gas from petroleum by-products are currently being priced. The comparative economic markets of coal to gas pro-duct have plenty of time to mature. There is an approximate twelve-year lead time needed to bring coal gasification plants on line which will be able to compete in the market place for natural gas and oil customers.

Jan 1, 1977

By E. D. Gálvez, L. A. Cisternas, R. Acosta-Flores, F. A. Lucay

Froth flotation processes are carried out in flotation cells that are grouped into banks, and these banks are interconnected, forming a flotation circuit. A literature review shows the existence of papers related to flotation circuit design based on mathematical programming. However, due to the complexity of solving the mathematical model in most of the work, it is considered that a small number of species is present in the feed to the circuit, which differs from practice. In addition, simple bank models are generally used. This paper presents a methodology for designing mineral concentration circuits that overcomes the problems mentioned. It allows the use of more suitable cell or bank models and the inclusion of several species. The methodology is based on two phases. The first phase identifies the set of optimal structures using discrete values of stage recoveries, solving several mixed integer linear programming (MILP) problems. In the second phase, the optimal design for each of the structures obtained in the previous phase is determined using a suitable model for the recovery at each cell or bank, which results in a mixed integer nonlinear programming (MINLP) model. The design of a copper concentration plant with eight species and the design of a zinc concentration plant with three species and five size fractions by species are used to validate the proposed methodology. The structure of the cells in the rougher and cleaner banks deliver structures that are novel.

By J. Paraszczak

Water-powered jackleg rock drills, introduced recently in South African mines are reported to be more efficient, faster and more comfortable to operate than conventional pneumatic drills. A comparative testing of both drill types was performed in Quebec. Based on its results and time studies done in the mines, water-powered drilling has been reviewed with regards to drilling rates achieved, infrastructure needed, side effects, health and safety considerations. This study shows that the application of water-powered drills may help increase footage drilled and improve working environment, but under specific conditions. The examples of such applications are given in the conclusions.

Jan 1, 1995

By Arthur W. T. Grimley

Hydraulic coal mining is being successfully practiced in China, U.S.S.R., Japan and Canada and in each country, excepting Japan where suitable sites are not available, the system is being expanded to either existing conventional mines or new mines. Productivity levels and economics at these mines are in all cases better than the productivities achieved in conventional mines in the same general localities. In the U.S.S.R. face productivities approaching 50 tons per man shift have been reported while in Canada the latest statistics show average face area productivity levels are in the region of 200 tons per man shift production monitor. In the United States hydraulic mining has not been actively pursued to the same degree and consequently there are no full scale hydraulic coal mines in operation or construction. Because many of the coal measures in the Western U.S.A. are generally somewhat similar to those being successfully hydraulic mined in Western Canada and parts of Siberia it is realistic to believe that successful hydraulic mines can be designed and developed in the Western U.S.A. Particularly if the vast technological base that already exists is used to improve on other people's ideas, systems, methods and equipment.

Jan 1, 1983

Refractory copper ores (CROs) in central Africa contain copper minerals that are locked up in a micacious solid matrix or associated with carbonate, sulfide and phosphate minerals. Several researchers have reported that the recovery of copper from CRO material by an acid-leaching process is not economically feasible, due to the presence of excess gangue-acid-consuming minerals such as calcites, dolomite, asbolane and iron oxides. Since the proportion of acid-insoluble copper (CuS) is about 28% of total copper and total free sulfur is extremely small, sulfide flotation was considered unfavorable. Consequently, hundreds of millions of tons of CRO material have been stockpiled specifically at the Nchanga Mine of Zambia. In terms of copper distribution in CRO material, a significant portion of total copper exists as carbonates (39%) and oxides (17%), while 28% of the copper is acidinsoluble (CuS). The rest of the copper is in the form of carbonates (16%) and (hydr) oxides (17%). This means that only about 72% of total copper is recoverable through the non-oxidative acid-leaching process. In this study, batch leach tests were performed on CRO solids (d95 = 95%) to establish the gangue acid consumption values at different feed pH values and to evaluate the leaching characteristics of copper, manganese and iron within the CRO material. Subsequently, continuous leach tests were performed on CRO solids (106 um, 80% passing) using optimum leach conditions derived from batch tests. This paper aims to show that sustainable copper recovery can be achieved by selecting leaching conditions whereby gangue acid consumption (GAC) values become significantly small and the final concentration of manganese and iron in the leach solution are appreciably low.

Nov 1, 2011

Refractory copper ores (CROs) in central Africa contain copper minerals that are locked up in a micacious solid matrix or associated with carbonate, sulfide and phosphate minerals. Several researchers have reported that the recovery of copper from CRO material by an acid-leaching process is not economically feasible, due to the presence of excess gangue-acid-consuming minerals such as calcites, dolomite, asbolane and iron oxides. Since the proportion of acid-insoluble copper (CuS) is about 28% of total copper and total free sulfur is extremely small, sulfide flotation was considered unfavorable. Consequently, hundreds of millions of tons of CRO material have been stockpiled specifically at the Nchanga Mine of Zambia. In terms of copper distribution in CRO material, a significant portion of total copper exists as carbonates (39%) and oxides (17%), while 28% of the copper is acid-insoluble (CuS). The rest of the copper is in the form of carbonates (16%) and (hydr) oxides (17%). This means that only about 72% of total copper is recoverable through the non-oxidative acid-leaching process. In this study, batch leach tests were performed on CRO solids (d95 = 95%) to establish the gangue acid consumption values at different feed pH values and to evaluate the leaching characteristics of copper, manganese and iron within the CRO material. Subsequently, continuous leach tests were performed on CRO solids (106 um, 80% passing) using optimum leach conditions derived from batch tests. This paper aims to show that sustainable copper recovery can be achieved by selecting leaching conditions whereby gangue acid consumption (GAC) values become significantly small and the final concentration of manganese and iron in the leach solution are appreciably low.

Jan 1, 2011

By J. Morris

Petro-diesel is a common collector for fine coal froth flotation but partitioning of diesel range organics (DROs) in process streams has not been widely studied. Preliminary research suggested that under normal dosing schemes total residual DRO in process waters should be limited to the sub-ppm water-soluble fraction (WSF). Further, polycyclic aromatic hydrocarbons (PAHs) should partition proportionately with DRO. The purpose of this study was to confirm these findings in laboratory flotation tests. Total DRO and specific PAHs were measured in tailings and concentrate streams, and coal recovery and ash rejection were tracked. Results show that concentrate waters consistently had higher DRO than tailing waters, and DRO in both streams generally increased with increasing diesel dosage. DRO again appeared to be limited to the WSF and PAHs tended to partition proportionately with DRO. Results indicate optimal flotation performance should generally coincide with minimal DRO partitioning to process waters. Under typical operating conditions residual DRO should not present an environmental concern; however, conditions should be avoided that allow significant overdosing of diesel.

Feb 23, 2014

By F. Dehghani, M. Kebe, H. Askari-Sabzkoohi, T. Ghosh

The depletion of bauxite reserves around the world has necessitated the search for viable alternative sources of aluminum. The major non-bauxite source of aluminum is alunite [KAl3 (SO4)2(OH)6]. Lixiviation is the common industrial process to recover aluminum from alunite. Due to the presence of quartz (40%) as the main gangue mineral, this process causes the formation of Sodium aluminosilicate and Potassium aluminosilicate complexes that leads to loss of alunite, and chemical reagents. Thus, pre-concentration of alunite is required to remove the gangue minerals. Because of the low degrees of freedom (DOF) of alunite, froth flotation, as a preconcentration method, is a viable alternative to increase selectivity in downstream processes. In this work, the possibility of Alunite preconcentration with micro flotation and mechanical flotation cells was studied. The influence of type and dosage of collector, pH, solid percent, particles sizes were considered on the flotation. Flotation tests were designed based on Taguchi method, followed by performing based on surface charge differential between alunite and quartz on direct and revers flotation. In the reverse flotation, Ca+ 2 and Ba+ 2 were used to activate the quartz surface. Under optimum conditions of reverse flotation, alunite grade and recovery were 40% and 62.1% respectively. In the direct flotation, the surface of alunite was activated by F- . The grade and recovery were 50 and 89%, respectively.

Mar 2, 2022

By Fengyu Ren, Kunpeng Yu, Gideon Chitomb, Qiangqiang Gao, Liqiang Ma, Jiangtao Zhai, Ichhuy Ngo

The penetration of rock fragments of overlying strata causes advanced ore dilution during drawing. The results of numerical and physical experiments showed that the proposed numerical simulation was applicable and the microscopic parameters of the model were reliable. The penetration under the variables of particle diameter ratio, density ratio, overlying strata thickness, and particle morphology was clarified. The penetration was quantitatively characterized by the discharge amount and the dilution rate. The experimental results showed that the diameter ratio and density ratio had a significant influence on the penetration. On the irregular shape of particles, the penetration is weakened. The overlying strata thickness had little effect on the penetration. This study could provide a theoretical basis for the full section uniform drawing, avoiding advanced ore dilution and further optimization of recovery rate.

Nov 13, 2023

By Angelina Anani, Nilufer K. B. Akbulut, Sefiu O. Adewuyi

Crucial information about safety, design and operation from ground movement data can be utilized in underground mines. Communicating the information and exploring new findings can be a challenge, however, in a decade where there is an ever-increasing volume and velocity of data due to advancements in mining technologies. This challenge escalates for geotechnical data as they are multidimensional, depending on the space and the rate at which they take place. To tackle this challenge, geotechnical engineers should focus on using simple yet compelling visualization of rock mass data in 3D. Competent visualizations of ground conditions as a trigger action and response plan (TARP) could ease the communication of safety concerns and the exploration of rock mass displacement and strain surrounding an opening at an underground mine. Therefore, this study focuses on using scientific visualization methods by rendering geotechnical data over the surface of a 3D mesh model to display TARP levels. The study was conducted at the East Decline of the San Xavier (SX) Underground Mine, a laboratory mine operated by the University of Arizona. The project aims to produce visualizations that optimize the use of geotechnical data in near-real time.

Sep 1, 2025

By Andrea Brickey, JUDITH BUABA, RICHARD AMOAKO

The global mining industry has recorded significant declines in accident and injury rates attributed to the advancement in technology, increased enforcement, and safety consciousness. A goal of the mining industry is to achieve zero injury and occupational illness on all mine sites, prompting increased research into ways to further reduce mine accidents. A machine learning technique known as multiclass logistic regression is applied on a 10-year injury dataset from the Mine Safety and Health Administration (MSHA) to determine a miner’s susceptibility to a class of injury and to help identify significant risk factors associated with different classes of injury. The data is aggregated based on injury classification to provide statistically relevant results. The analysis identifies specific risk factors that influence a mine worker’s susceptibility to a given class of injury, i.e., non-fatal with no days lost or restricted activity, non-fatal with days lost and/or days of restricted work activity, and fatal and total permanent or partial permanent disability. These factors include miner’s age, mine type (coal vs. non-coal), experience on the current job (years), shift start time, employment type (operator vs. contractor), mining district, and type of accident. The results of the analysis indicate that a miner’s experience on the job, i.e., the number of years worked in a current job, is a significant risk to injury occurrence, even for those with decades of total mining experience. We further show the differences and similarities between the surface and underground mine incidents.

Nov 3, 2020

By Richard L. Profio

A practical analysis of the three basic elements of a mining shovel's productive capacity. Payload Speed Reliability Improved dipper fill factor is explored referring to the latest generation of wide dippers combined with higher "bank horsepower" capabilities of modern drive systems. Cycle time improvement is reviewed including overall attachment geometry and coordination of motions. A specific case study is detailed. Basic reliability of welded structures, machinery components, and electrical systems are related to operating costs. Three basic elements determine a mining shovel's long term productive capacity: 1) Average payload per cycle. 2) Average cycle time; and 3) Reliability. This paper deals with productivity gains that are possible with existing shovels as well as new equipment.

Jan 1, 1984

By H. D. Lelono, M. Walden, G. Johnson

3D modelling can be used throughout the mine lifecycle and has proven to be a powerful tool for consultants and mining companies. One of the most significant benefits of 3D models is their ability to enhance collaboration, communication, and understanding between the mine owner, design engineers, and other relevant stakeholders that have a shared interest in responsible mining and site management. Tailings and mine waste management is an interdisciplinary effort that requires effective coordination and communication between a wide range of consultants, operators, and stakeholders alike. The increased emphasis on Environmental, Social, and Corporate Governance (ESG) highlights the importance for mine operators to engage and communicate with all parties involved in the planning, permitting, operation, and closure of mine sites. 3D models are valuable tools that can be used for development of geotechnical conceptual models, allowing for improved design and monitoring of Tailings Storage Facilities (TSFs). A clear conceptual understanding of a TSFs subsurface geology and foundation characterization is essential for proper tailings management, design, and planning. Visualization with 3D modelling can simplify the interpretation of the, oftentimes intricate, mine sight subsurface settings and allows for quick and effective geotechnical conceptualization. 3D models can be used to identify data gaps, optimize field investigations, and streamline the development of numerical stability or groundwater models. They can help communicate the complex nature of subsurface and TSF interactions in a clear, concise, and accurate manner to both technical and nontechnical stakeholders. This paper discusses some of the benefits of 3D modelling in relation to geotechnical analysis for tailings management and provides methodologies for how to improve upon some methodologies that are considered industry standards.

Feb 1, 2023

By J. C. Norman

The United States was the world’s largest producer and consumer of boron compounds during 1995. According to estimates from the US Geological Survey(USGS), boron mineral concentrate and chemical production in the United States totaled an estimated 1.1 Mt(1.2 million st) yielding 602 kt (663,000 st) of B2O3 for an estimated value of $462 million. This level of production exceeded 1994 revised production figures by about 9%. The United States continued to provide nearly all its own boron supply while maintaining a strong position as a source of sodium borate products and boric acid to foreign markets. During 1995, about 900 people worked in domestic boron mines and plants, about the same as in1994. USGS estimated total world production of boron during 1995 to be about 3 Mt (3.3 million st), yielding about 1.6 Mt (1.8 million st) of B2O3. World production in 1995 was about equal to revised 1994 levels.

Jan 1, 1996

By S. Gering, R. Ruiz, C. H. Calderon-Arteaga, J. Barrios

"Located in the northeast corner of Zacatecas State, Mexico, the Peñasquito operation is comprised of the Peñasco and Chile Colorado (Brecha Azul) deposits. Openpit mining (prestripping) began in 2010 and full production commenced during 2011. The openpit mines feed both a sulfide concentrator (mill) and a heap leach pad. The project is owned by Goldcorp Inc. Peñasquito is a poly metallic deposit with Au, Ag, Zn and Pb being recovered as payable metals.As a consequence of lower grade ores expected with advancing mine life, Peñasquito is facing a declining metal production profile. To maximize returns and asset value, plant modifications, including the addition of a carbon prefloat circuit and a pyrite leach circuit to improve recovery, are currently being undertaken. This carbon prefloat circuit will enable the recovery of precious and base metals from carbonaceous sediments. This material is currently being stockpiled. With the associated increase in complexity in the process circuit, the requirement of the ore control system to accurately predict ore feed characteristics is critical to maximizing metal recovery at the Peñasquito operation. The addition of the carbon prefloat circuit was also a key driver in allowing the Chile Colorado openpit to be developed.These conditions alongside Goldcorp’s drive to increase profitability and maximize net asset value has created challenges. These challenges are numerous and multifaceted. However, the ability to accurately route materials from the ore control system is critical to site success, and some of these challenges have been overcome by the adoption and implementation of a new ore control (OC) technology. Examples of these technological innovations in the ore control program are discussed in this article and include improvements in geomodeling, material routing and reconciliation. Successful implementation of these elements has led to significant improvements in selectivity, performance and data management, while reducing the variance between planning and execution, thus helping to drive overall improvement across the operation."

Jan 7, 2018

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