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By M. Z. Rashad

The purpose of this paper was to compare the covariance and multiquadric functions in same mining and geological applications. The basic principals of the two techniques are covered briefly. Similarities and dissimilarities of the covariance and multiquadric functions are discussed geometrically, mathematically and practically. A 14 by 16 kilometer square area in Baharia Oasis, Western Desert of Egypt, was selected for a detailed comparative test. The gravity anomalies of forty-eight test stations were computed by using the data of sixty-three control stations. The results indicated that the covariance function is quite better than the multiquadric one. On the other hand, the multiquadric function more simple in computation than the other one, which needs to precalculations such as semivariogram and covariogram. Moreover, multiquadric equations are based on geometrical and physical considerations rather than covariance functions.

Jan 1, 1990

By Karoly (Charles) Kocsis, Kyle A. Scalise

Understanding the climatic conditions in underground mines is necessary for efficient ventilation design, cost savings, and to ensure the health and safety of mine workers. Large volumes of ventilation and climatic data including air volume, barometric pressure, dry bulb temperature, and relative humidity were collected at active underground precious metal mines in Nevada, which allows for the determination of wet bulb temperature and other key parameters. Through the utilization of neural networks, the wet bulb temperature at the bottom of the intake shafts is predicted, while taking into account the “thermal flywheel effect” (TFE). Wet bulb temperature is one of the most important climatic parameters to model and understand because it significantly affects the work conditions and the cooling capacity of the ventilating air. The accurate prediction of the dry bulb and the wet bulb temperatures at the bottom of intake shafts is critical when assessing the climatic conditions in future underground mines and deciding onwhether a cooling system is needed to assure adequate working conditions throughout themine. By utilizing accurate predictions of wet bulb temperatures and other climatic parameters, mine personnel will be safer as reported by Bluhm et al. (2003), and a more accurate ventilation design can be achieved resulting in major cost savings for underground mines.

Mar 3, 2021

By L. Figueroa

Electrochemical methods have potential to treat waters impacted by mining, while simultaneously producing a recoverable metal product to off-set treatment costs. Mining-impacted waters may present challenges with electrochemical treatment due to low concentrations and complex solutions of numerous dissolved metals. This paper presents an evaluation of the potential strengths and limitations of abiotic electrowinning of mining-impacted waters. In particular the impacts of chemical composition on metals removal are evaluated. Results of bench-scale experiments demonstrate the potential to remove metals on the cathode (copper, cadmium, lead), as well as the anode (manganese). Pre-treatment for iron and aluminum may be needed and post-treatment pH adjustment would be necessary. INTRODUCTION Due to continually increasing demand for metals, new technologies and innovative applications of existing technologies are needed to recover metals from mining-impacted waters. Electrochemical methods have long been used for metallurgical processes with solutions containing high concentrations of the target metal. However, electrochemistry also has potential to treat waters with lower metal concentrations, while simultaneously producing a recoverable metal product to offset treatment costs. Electrochemical water treatment may have several benefits over traditional alkaline treatment for acid rock drainage (ARD). Sludge produced from alkaline treatment has high water content that is difficult to dewater, even for treatment plants producing a relatively high-density sludge. For example, the Argo Tunnel Water Treatment Facility (Argo Facility) in Idaho Springs, Colorado uses hydrated lime to produce a high-density sludge with a solids content of 20 to 25 percent and filter cake with solids content from 30 to 35 percent [1]. Furthermore, costs for managing the sludge are significant, approximately $90,000 per year for treating approximately 150 million gallons of water [1]. Although not the case for the Argo Facility, sludge produced from alkaline treatment of ARD has potential to be classified as hazardous. Disposal of sludge also opens up the potential for future liability depending on the sludge’s chemical stability and methods of disposal. In contrast to alkaline treatment, electrochemical treatment produces metals in elemental and other highly-dense forms on the cathode. If metals concentrations and flow rates are sufficiently high, the metals recovered may help offset overall treatment costs. In addition, sludge production would be reduced, if not eliminated altogether, thereby reducing both disposal costs and potential future liabilities as well.

Jan 1, 2019

By P. T. Bissert, T. J. Lutz, J. A. Yonkey, G. T. Homce

"The U.S. National Institute for Occupational Safety and Health (NIOSH) has been researching refuge alternatives (RAs) since 2007. RAs typically have built-in pressure relief valves (PRVs) to prevent the unit from reaching unsafe pressures. The U.S. Mine Safety and Health Administration requires that these valves vent the chamber at a maximum pressure of 1.25 kPa (0.18 psi, 5.0 in. H2O), or as specified by the manufacturer, above mine atmospheric pressure in the RA. To facilitate PRV testing, an instrumented benchtop test fixture was developed using an off-the-shelf centrifugal blower and ductwork. Relief pressures and flow characteristics were measured for three units: (1) a modified polyvinyl chloride check valve, (2) an off-the-shelf brass/cast-iron butterfly check valve and (3) a commercially available valve that was designed specifically for one manufacturer’s steel prefabricated RAs and had been adapted for use in one mine operator’s built-in-place RA. PRVs used in tent-style RAs were not investigated. The units were tested with different modifications and configurations in order to check compliance with Title 30 Code of Federal Regulations, or 30 CFR, regulations. The commercially available relief valve did not meet the 30 CFR relief pressure specification but may meet the manufacturer’s specification. Alternative valve designs were modified to meet the 30 CFR relief pressure specification, but all valve designs will need further design research to examine survivability in the event of a 103 kPa (15.0 psi) impulse overpressure during a disaster. BackgroundThe Mine Improvement and New Emergency Response Act of 2006, known as the Miner Act (U.S. Department of Labor, 2006), was enacted in the wake of three mine accidents involving explosions or fire that claimed 19 lives that year. Intended to help improve underground coal mine accident preparedness, the Miner Act includes provisions that target mine safety issues in areas such as emergency response planning; adoption of new technology; training and education; and mine safety standards enforcement. Section 13 of the Miner Act specifically directed the U.S. National Institute for Occupational Safety and Health (NIOSH) to provide for research into the effectiveness and viability of refuge alternatives (RAs) for underground coal mines, and the U.S. Department of Labor to act on the results of such research, as appropriate. These mandates culminated in the 2009 adoption of changes to the Title 30 Code of Federal Regulations, or 30 CFR, mining health and safety regulations (U.S. Department of Labor, 2008), requiring underground coal mines to supply mine emergency RAs and associated components so as to provide a life-sustaining environment for persons trapped underground. Such RAs can be either selfcontained mobile units or built-in-place facilities. The regulatory changes also include provisions establishing requirements for the approval of RAs and their components by the U.S. Mine Safety and Health Administration (MSHA), among which are numerous criteria for providing a safe breathable atmosphere under positive pressure within the RAs. One criterion for maintaining a safe RA atmosphere is the inclusion of an air pressure relief valve that will activate at a maximum of 1.25 kPa (specified as 0.18 psi, or approximately 5.0 in. H2O), or as specified by the RA manufacturer, above mine atmospheric pressure in the RA (U.S. Department of Labor, 2008)."

Oct 1, 2016

By M. Canty

An innovative biological treatment system designed to detoxify cyanide and nitrate and immobilize metals from cyanide leach operations is described. A pilot-plant demonstration was conducted to detoxify cyanide and immobilize several metals from a process stream at the McCoy/Cove Mine. Testing was performed under the EPA's Mine Waste Technology and Superfund Innovative Technology Evaluation Demonstration Programs. This technology was successful in detoxifying cyanide and effective in removing metals. The pH was consistently neutralized and nitrates were successfully removed. Results show that biological treatment can offer an innovative, cost-effective alternative for the treatment of mining wastewaters.

Jan 1, 1999

By Z. Kokesz

The following paper presents the results of geostatistical studies of the selected hard-coal deposits in Poland. Geostatistical methods were applied mainly to the characterization of variability structure of the coal seams thicknesses as well as sulphur and ash contents in the coals. Results imply that the accuracy of coal reserves estimations can be improved if kriging method is applied. Kriging allows predicting more precisely the values of such parameters as thickness and sulphuring content.

Jan 1, 1993

By Thomas F. Clemens

This paper covers various changes in government regulations, taxation, and legislation for the past two plus years and the up- coming one. Part of the paper will discuss recent business conditions and how they have affected the cement and lime industry.

Jan 1, 1983

By J. A. Organiscak

Enclosed cab filtration systems are typically used on mobile mining equipment to reduce miners? exposure to airborne dusts and diesel particulates generated during mining operations. Various filter configurationscan be used within the heating, ventilation and air conditioning (HVAC) systems of cabs to remove the airborne contaminants. The air cleaning performance of cab filtration systems is highly dependent on the efficiency of the air filters, the number of filters used and their placement within the HVAC system. This paper shows how to mathematically model cab filtration systems and illustrates a methodology for developing other cab filtration system design models. Node diagrams of several filtration system circuits are illustrated with their mathematical models at steady state airflow and concentration conditions. Laboratory and field data are presented to demonstrate the validity and utility of modeling enclosed cab air cleaning performance. The paper concludes that incorporating multiple filters throughout the HVAC system improves the air cleaning performance and robustness of the cab filtration system design

By Craig J. Brown

Despite its great potential utility, ion exchange has only achieved limited application in hydrometallurgy. To a significant extent this is due to the limitations of conventional ion exchange process design as well as the properties of the ion exchange resins themselves. Over the past decade several new ion exchange resins have been introduced with properties that make them potentially very useful for various hydrometallurgical separations. In addition, a novel ion exchange process called Reciprocating Flow Ion Exchange or Recoflo, which has been employed in the metal finishing industry for the last dozen or so years for chemical recovery and effluent treatment, has been shown to offer a number of unique and significant advantages over conventional I.X. technology.

Jan 1, 1984

By M. P. Smith, C. Hughes-Narborough, Y. T. Man

"Money and reputations can be lost in bad projects. Causes of bad mineral processing projects include poor contract definition and purchase of equipment without adequate test work. However, the root cause of many of the problems that can lead to bad projects is not any inanimate object, bad weather or catastrophic natural event but the people working on the projects. Because the people are so critical to the success of a mineral processing project, one must have suitably qualified and experienced people (SQEP) in all key positions. Characteristics that define SQEP include people who have successfully executed projects of similar size before; have undertaken projects treating the same minerals and producing the same valuable products and people who are familiar with designing, operating and implementing the required technologies and unit operations.To minimize the likelihood of future bad mineral processing projects, five recommendations are put forward in relation to the people aspect of a project.1. Attempt to retain SQEP during any down turn in the mining economic cycle so thatthe knowledge and experience can be kept within the industry.2. Increase the effort in attracting young people into the industry and retaining them.3. Set up robust training program to give young professionals a firm foundation of what real life projects and operations are like.4. Provide mentoring and continuous training for people after they have completed their formal graduate training program. Their career progression should be appropriately monitored and controlled.5. People working in projects must be exposed to as many detailed design and other finer issues as possible so that they can comprehend the amount of work required to deliver a project successfully."

Aug 1, 2016

By S. J. Jung

In recent years, the use of shotcrete, a practice familiar to the mining industry, has been on the increase. This research has come about because of the recognized need for a safe, easy way to line small diameter bored raises (less then 150cm). Up until now, an operator has gone down the raise and applied the concrete lining manually, using the shotcrete method of application. With an automated system, there would be no man positioned in the bore itself. All control functions could be commanded from a central location. Shotcreting in the confined space of a small diameter bored raise presents problems that can be overcome by the application of shotcrete using a remote system.

Jan 1, 1994

By J. Organiscak

A majority of continuous mining machines employ a water spray system and a machine-mounted flooded-bed scrubber to suppress and capture dust during coal mining. These machine-mounted dust control systems must be designed to function within the localized face ventilation system at the mining section to control both dust and methane. Spray systems can impede or improve the scrubber effectiveness in controlling dust or methane at the mining face. Laboratory experiments were conducted to examine the effect of spray type, spray pressure, machine body blocking sprays and scrubber airflow on dust and gas levels, while using a 12.2-m (40-ft) exhaust ventilation curtain setback from the face. These experiments were conducted with the mining machine positioned at the end of a simulated 6.1-m (20-ft) sump and slab cut. Results indicate that the hollow cone nozzles with blocking sprays best complement the flooded-bed scrubber performance in an exhaust ventilation system. This external spray system notably reduced dust and gas levels on the off-curtain side of the mining machine for both the sump and slab cut compared to the flat spray nozzles. Higher scrubber airflows reduced dust and gas levels on the curtain side and in the return of the continuous mining machine. The remote operator position, located on the off-curtain side and parallel to the inlet end of the exhaust curtain, sustained the most stable and lowest dust levels around the mining machine.

Jan 1, 2010

By Stuart Lister

"When MacLean Engineering chairman and founder Don MacLean got the first question from a minesite about the possibility of addressing ventilation limits through incremental fleet electrification, he was intrigued. It was back in 2015, and the MacLean scissor bolter was already diesel-electric (jumbo trailing cable), so it made sense to him that if they could engineer a battery drive system for the unit’s tramming cycle, they would have the inaugural electric vehicle (EV) MacLean unit.At that time, there were not any entirely diesel-free hard rock mines in existence on the planet, and that remains the case to this day — although the Borden project in northern Ontario is progressing toward that goal (see page 33). This meant there was essentially zero market demand for battery electric vehicles as well as a complete lack of battery technology to address the battery electrification of heavy haulage. Heavy haulage is the part of a typical mine’s mobile fleet with the largest footprint when it comes to diesel particulate emissions, greenhouse gases and wasted energy in the form of heat.Three years later — the wave of battery electrification that is currently picking up speed across the mining industry promises to hit full swing by the early 2020s when a slew of new build, diesel-free mines will start construction. But this movement toward emissions-free mobile fleets is not a completely new phenomenon. Instead, it is an updating of mining technology from a previous generation. What is going on now is the re-electrification of mining. Up until the 1960s, early generations of battery technology (lead acid) and electric locomotive systems were the norm for material and ore haulage in Canada and elsewhere.The thought of a coming paradigm change in mining was particularly pertinent to Don MacLean back in 2015, as he had been part of the era that ushered in the first generation of rubber-tire diesel equipment, when he was a divisional foreman with Inco in Sudbury in the 1970s. He was part of the operating team that was tasked to build a rail loop on one extraction level of the mine. At that time, events on the ground overtook the project, as diesel-powered mobile equipment became a viable option. Once the first diesel scoop was introduced at Creighton #3 shaft, it was clear what the power, haulage capacity and mobility could do for operations and that era of electric rail haulage underground was effectively over."

Jan 10, 2018

By David H. Carlson

Mechanical sorting of "poor" rock accumulated from past native copper mining operations has been under study at the Michigan Tech's Institute of Mineral Research for several years. Prior to this work, the poor rock dumps totaling approximately 9 million tons containing an estimated 35-70 million pounds of copper (1) have been considered mainly as a local source of road aggregate used from time to time and consequently of minor value. An electro¬mechanical sorting machine developed by International Sorting Systems Corporation of Santa Barbara, California has been tested for preconcentration of the waste rock before conventional milling (2,3). The ISSC machine has possibilities for underground preconcentration of crushed mine-run native copper ores. The objective of the study described here was to provide information about limi¬tations on sortability due to characteristics of the ore and present crushing practices. When the native copper mines were in operation prior to termination in 1969, two types of ore were produced, amygdaloidal and conglomeritic. In the first type copper occurs in vesicles left by gas bubbles entrapped during rapid cooling of the tops of lava flows. The conglomeritic ore beds consist of rounded pebbles and fragments cemented together by calcite, epidote, chlorite, and feldspar; the copper occurs around pebbles, in cracks, and sometimes as partial or total re¬placements of pebbles. The copper in the conglomeritic ore usually is in finer grain sizes than that in the amygdaloidal ore, and large (plus 4 inch) copper masses are virtually absent.

Jan 1, 1970

By V. Castranova, L. Wu, K. Van Dyke, J. Gutierrez, V. Vallayathan

Since it has been demonstrated that silica caused phagocytic cells to activate lipoxygenase metabolism of unsaturated fatty acids we thought selective inhibition of this metabolic pathway might be helpful in treatment of silicosis. It is known that lipoxygenase metabolism plays a role in the pathogenesis of a variety of inflammatory and hypersensitivity conditions. Further, it is believed that the alveolar phagocytic cells which engulf silica begin the inflammatory cycle which produces the metabolic products, cytokines and growth factors which causes fibrosis in the lung. There have been indications that drugs which inhibit lipoxygenase can inhibit fibrosis from other causes. Previously, we developed a method which detects the activity of lipoxygenase metabolism by measuring free radical oxidation via light production or chemiluminescence (CL). We decided to apply this method to phagocytic cells that would be found in the lung in the presence of silica with and without newly developed inhibitors of the lipoxygenase reaction. We used drugs which inhibit lipoxygenase directly including AA861 (TAKEDA), A63162 (Abbott), and an inhibitor that scavenges free radicals produced from the lipoxygenase reaction, nordihydroguairetic acid. In addition we used an indirect inhibitor, tetrandrine. We found drug inhibition of silica activated CL from alveolar macrophages, neutrophils and human leukemia (HL-60) cells differentiated with DMSO. Nordihydroguairetic acid 2x10-5M produced almost complete inhibition in all three cell types. In human leukemia cells (HL-60) A63162 and tetrandrine were equally inhibitory at 42% while in human neutrophils A63162 and tetrandrine were less active 22 and 10% respectively. In macrophages A63162 and AA861 were less than 50% inhibitory to cellular CL at 2xl0-5M. Direct assay of tetrandrine (2x10-5M) with sodium arachidonate and soybean lipoxygenase reveals no inhibition. All antilipoxygenase drugs regardless of mechanism were inhibitory to cellular chemiluminescence from all three types of phagocytic cells. These drugs alone or in mixtures could prove useful in treatment of silicosis.

Jan 1, 1991

By Ankit Jha, Javad Sattarvand, Aaron Young

Blockchain technology is one of the prominent disruptive technologies that are being implemented in several disciplines. The application of blockchains in the mining and mineral industry can provide utility to several processes especially when the industry is undertaking digital transformation. The governing principles of blockchain technology are applicable in undertaking transformation in several processes within the mining industry. This study investigates the applications of blockchain technology within the realms of the mining industry and identifies key areas of implementation. A systematic review of publications on academic platforms relating to blockchain technology in the mining industry did not retrieve a considerable number of articles. Consequently, a thorough review of white papers and articles authored by individuals on use cases within the mining industry is compiled and presented in this review article. This review article identifies all the potential areas within the mining industry where blockchains could provide value and improve processes through their implementation. The broad area of implementation of blockchains includes supply chain, traceability in spares parts, contract management, regulatory compliance and cybersecurity.

Mar 1, 2024

By B. W. Cavender

Capital investments are made for a variety of purposes, from providing incremental capacity at existing operations to developing and implementing new technologies intended to radically improve a company's capabilities. These projects generate very different business opportunities and create value in distinctive ways. For incremental improvements, the capital budgeting process assures at least a loose fit between short-term goals and readily available resources. However, the criteria used to evaluate capital projects often prevent a company from committing to more aggressive goals that lie beyond the firm's current abilities or resources. Such projects may not have clearly identifiable future cash flows, and the degree of interaction with other projects and the nature of the risk incurred may be difficult to estimate. Additionally, by focusing only on quantifiable benefits, the budgeting process often fails to recognize "soft" improvements such as increased operating flexibility or new knowledge generated by such projects. By rejecting these projects, the capital budgeting process may actually harm the company's future competitive position.

Jan 1, 1998

By R. Bishop, J. Baggett, J. Monsalve, N. Ripepi, A. Soni

Technology plays an ever-increasing role in improving the safety and efficiency of mining operations. Laser scanning and photogrammetry are two useful methods for capturing 3D digital representations of real world objects. While both technologies have been applied to the mining industry in numerous ways, the practical applications in an operating underground limestone mine has been tested for this paper, including for visualization and site characterization. Each technology is capable of creating highly detailed geospatial point clouds, but are all point clouds created equal? This paper presents a comparison of a laser scan and photogrammetry of a limestone pillar and addresses the strengths and limitations of each method for creating digital models of operating underground limestone mines. INTRODUCTION The United States crushed stone business is a ~$14 billion per year industry representing 1,430 companies which operate 3,782 mining operations across the 50 states. In 2017 alone, 1.33 billion tons of crushed stone was produced with 76% used predominately for road construction and repairs, but also for the production of cement, lime, chemical and agricultural uses. Over 70% of domestic crushed stone producers source their material from limestone and dolomite deposits, with currently only 82 mines (2%) operating underground (USGS, 2018). Underground mining requires a different technical skillset, and poses great challenges for production that must be both safe and economical. Therefore, there are many risks that an operation must mitigate in order to produce underground limestone. Some of the challenges in underground limestone mining involve geological hazards that are unique to the rest of the industry. The geologic features such as faults and weaknesses can be difficult to assess in a production environment (NIOSH, 1998). The consequences of failure due to improperly designed underground mining ground support systems, such as from a roof failure, are not only life threatening for the miners themselves, but can easily shut down an entire mining operation.

Jan 1, 2019

By D. Yeager

Researchers at the U.S. Bureau of Mines have successfully used a genetic algorithm to tune computer models of three column flotation units simulating a separation circuit. The computer models rely on empirical constants that are selected so that the models accurately predict the performance characteristics of individual column flotation units. Unfortunately, these empirical constants have traditionally been selected using a time consuming trial and error process. A new and more efficient approach to selecting empirical constants for computer models has been developed. A genetic algorithm has been used to select the empirical constants for column flotation models used to simulate a three column circuit. Genetic algorithms are search algorithms based on the mechanics of natural genetics. They rapidly locate near optimum solutions in difficult search spaces. Bureau researchers have used these innovative search algorithms to dramatically reduce the time needed to select empirical constants for column flotation models. The approach is applicable to the selection of empirical constants for numerous other computer models.

Jan 1, 1995

By X. Song, Q. Zhang

"The development of fracture zones in surrounding rock mass has significant impact on the stability of underground mine roadways. Detection of the fracture zones is of compelling importance for maintaining roadway stability as well as for safe and speedy excavation of the roadways. This paper presents a study conducted at Dong Bao Wei underground coal mine, where the roadways were developed in diabase rock mass. The roadways suffered severe damages, including sloughing and excessive floor heaving. The borehole imaging technique was applied in the study to observe and detect fracture zone development surrounding the roadway openings. Based on the borehole imaging studies, new roadway support systems were proposed to improve the stability. INTRODUCTION At the Dong Bao Wei Coal Mine three main roadways of the west wing were excavated. The three roadways had semicircle arch cross sections and were at a depth of 650 meters, each being about 750 meters in length. The roadways were driven through a section of thick diabase intrusion, which was softened by water with reduced strength and may turn into powder form under weathering. Site investigation indicated that the roadways in diabase intrusion zone were badly damaged due to severe deformation, and very serious roadway sidewall sloughing and spalling accompanied by severe floor heave often occurred.(Figures 1 and 2) In order to ensure the normal use of the roadway, undercuts were excavated. However, this operation seriously affected the roadway construction progress and increased the amount of roadway support operations as well as the roadway maintenance costs. Furthermore, a roof fall accident occurred in nearby drilling site. The investigation indicated insufficient support provided for the roadways which imposed significant safety hazards and would have serious impact to mining production and subsequent mining activities.The support of the main roadways is a critical task and is the focus of the underground opening excavation work at the mine, since more than 40 years of service life is required from these main roadways. For these roadways, large cross sections with high degree of stability and minimal amount of deformation should be maintained. Therefore, providing sufficient and appropriate roadway supports is of significant importance to the coal mine. In this paper, in order to optimize the roadway supporting system, studies were carried out on the geological structures, lithological characters, roof bolt anchoring features and suitable anchoring layers. The studies were aimed at ensuring the stability of mine roadways, reducing the roadway maintenance costs and providing a safe mine passageway for orderly production and progressive development of the mine"

Jan 1, 2016