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By J. Fritz, V. Gangrade, J. Briton, K. M. Ajayi, M. L. Harris, G. Cole, M. Young

Mine workers using diesel-powered equipment experience the highest occupational exposure to diesel particulate matter (DPM). This problem could be aggravated in underground stone mines due to their unique ventilation challenges with the large openings for airflow. Hence, adequate ventilation in these mines requires a combination of effective ventilation planning and delivering needed air quantities using auxiliary fans and stoppings. To meet this challenge, the National Institute for Occupational Safety and Health (NIOSH) developed the Air Quantity Estimator (AQE) software as a mine planning tool to help underground mine operators estimate the air requirements necessary to dilute DPM in the main air stream to statutory levels. The major parameters required for the calculations are the engine’s horsepower, DPM emission rate, the percentage operating time, catalytic converter efficiency, and filter efficiency. In efforts to provide major updates to this software, this study describes the recent development of a revised version of the Air Quantity Estimator (AQE 2.0). With the revised version, users have access to a comprehensive database of over 40,000 pieces of equipment, can define their specific target DPM level, and can create specific equipment for a customized database, in addition to having an improved easy-to-use interface. The software output provides an estimated total airflow necessary to dilute DPM based on the projected emissions, and the user can generate a related results report. The results also provide the mine personnel with a tool to identify vehicles that are high DPM contributors and could further be used to optimize the ventilation requirement by making changes to the percentage operating time of the engine. This software provides the mine with a user-friendly tool that could help reduce the DPM exposure of workers.

Feb 1, 2023

By H. E. Wyslouzil

The highly competitive nature of the international iron ore market has forced producers to improve the quality of their pellets. The demand for low acid pellets suitable for direct reduction has resulted in an increase in the number of plants utilizing reverse froth flotation for silica reduction. Column flotation is being favoured for this service due to the low capital and operating cost of the equipment, as well as improved metallurgical performance when compared to conventional flotation cells. This paper describes the benefits of column flotation and discusses some important aspects of circuit design.

Jan 1, 1993

By R. S. Saunders

Congress, under the Nuclear Waste Policy Act of 1982, as amended, charged the U.S. Department of Energy (DOE) with the responsibility for safe and permanent disposal of high-level radioactive waste in a geologic repository. The waste will consist of spent fuel from commercial nuclear generating plants and reprocessing activities. Under direction of this law DOE is currently evaluating Yucca Mountain in Southern Nevada as the candidate site for a potential high-level radioactive waste repository. Presidential, Congressional and State of Nevada approval are needed for repository construction to proceed after successful completion of site characterization and recommendation of the site to Congress. The DOE will submit a license application to the Nuclear Regulatory Commission (NRC) to construct the geologic repository. Following successful construction DOE will update its license application to operate the repository.

Jan 1, 1993

By W. H. Langer

Quaternary alluvial deposits in the modern stream channel of the Agua Fria River west of Phoenix, Arizona, is mined and processed to provide aggregate to the greater Phoenix area. The alluvium occurs as three distinct, stratigraphic layers. Samples from each of the three layers were examined for gravel clast lithology, grain size distribution, and engineering tests, which revealed noteworthy differences in properties. The engineering properties of the gravels are dependent on a combination of factors including gravel clast lithology, the distance the gravel clasts have been transported from their source areas, the age of the deposits, and the degree of weathering. Knowledge of these characteristics may affect the methods that aggregate operators employ to extract and process gravel from the Agua Fria River.

Jan 1, 2010

By Ulrich Benatzky

Rheinbraun AG, Germany, is the management company of the mining and raw materials division of RWE AG. Rheinbraun's core business and major functional area is opencast lignite mining in the Rhineland. The characteristic feature of opencast mining is continuous operation using bucket-wheel excavators, belt conveyors, and spreaders. The report gives a survey of the conveyor systems used. In addition to the general performance data of these belt conveyors, this report will deal in particular with major components, such as drive stations and individual mechanical components (e.g., conveyor belts, pulleys, gears, couplings, brakes, scrapers), as well as monitoring systems. Finally, an assessment of the conveyor systems, together with future developments, will be given.

Jan 1, 2000

By Don Cchultz

The United States Forest Service, as a land managing agency, is responsible for the surface administration of National Forest lands. The basic objectives of management are protection and utilization of renewable resources such as water, forage, timber, wildlife, recreation, and clean air. Much of the National Forest land in this country is open to mineral prospecting and development. When large de-posits of minerals are extracted from the forest environment, especially by surface methods, there are oftentimes conflicts between accepted mining methods and the objectives of other resource management goals. Such is the situation in Southeast Idaho where several members of the phosphate industry are operating on and adjacent to the Caribou National Forest. In 1966, the phosphate industry and the Caribou National Forest became mutually concerned with the problems of rehabilitating mined areas and minimizing potential damage to adjacent forest areas. A Cooperative Administrative Study was initiated with industry supporting the Forest Service financially and with equipment, material, and manpower, as well as interest and enthusiasm. The objectives of the study are to provide basic, applicable information pertinent to: 1. Protecting the quality of water emanating from mined water-sheds. 2. Providing for soil stabilization on mined areas. 3. Returning mined areas to surface resource production. 4. The feasibility of making mined areas esthetically acceptable. It was concluded that the following separate--yet intergrated--fields should be studied in order to obtain the desired information:

Jan 1, 1971

By Jafar Safarian, Leiv Kolbeinsen, Stian Seim, Hossein Salehi

The present work aims to investigate the link between the oxidation and reduction of a weathered ilmenite concentrate in terms of phase transitions, microstructural changes, and element distribution. An ilmenite concentrate sample was pelletized and fired at 1000 °C in air, and as a result, the pellets were oxidized. The oxidized pellets were reduced by hydrogen gas at 1000 °C, which yielded almost complete metallization of the iron content of the pellets. The ore and the pellets were characterized in each step by XRD and SEM techniques, and distribution of elements and phases were investigated. Ilmenite, pseudorutile, and rutile were the main phases detected in the ilmenite concentrate sample, and depending on the weathering degree of the particles, different fractions of the phases were identified in their microstructure. It was found that irregular rutile grains dispersed in a pseudobrookite matrix is the morphology of the oxidized ilmenite phase. However, increasing microcracks and porosities were the only microstructural changes in the pseudorutile phase after oxidation in air. Studying the specific types of the ore particles and their oxidized and reduced forms indicated that the phase distribution in the ilmenite ore particles dictates the phase distribution in the oxidized and reduced ones. Results show that the morphology of the reduced particles includes a titanium (III) oxide matrix in which reduced iron globules are dispersed.

Feb 8, 2021

By E. Taskin

Diasporic bauxite from the Mugla-Milas region was mechanically activated in a planetary mill for different activation times and the structural changes were examined by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and specific surface area analysis (BET ? Burnauer, Emmett and Teller). Non-activated and activated bauxite samples were leached directly in alkaline (Na2O) solution at atmospheric conditions and the activation procedure led to the amorphization and structural disordering of the diasporic bauxite structure, which increased the dissolution efficiency. Effects of milling speed, liquid/bauxite ratio and leaching time on alumina extraction in direct alkaline leaching of diasporic bauxite were also studied. The alumina extraction was ~7% for non-activated bauxite and ~70% for activated (75 minute) bauxite. Key words: Diasporic bauxite, Mechanical activation, Alkaline leaching, Alumina extraction

Jan 1, 2009

By C. Sun

With complex component, higher salt content, low biodegradability, DSD acid oxidation wastewater could not be efficiently dealt with traditional methods. It is pointed that the coal water slurry could be made with DSD acid oxidation wastewater of different concentration and the density of coal water slurry could be up to 70%, while its viscosity is only 850~930 mPa?s. The coal water slurry could be perfectly jetted and burnt under different conditions. The higher density the DSD acid oxidation wastewater has, the better properties the coal water slurry have. The pollution components and characteristic group of DSD acid oxidation wastewater are similar to the additives of coal water slurry, so it could be used as a kind of usable additive of water coal slurry. It is so reasonable and feasible to make coal water slurry with DSD acid oxidation wastewater that the pollution of DSD acid oxidation wastewater can be solved completely.

Feb 23, 2014

By S. K. Kawatra

Outokumpu Electronics has designed a new on-line coal slurry ash analyzer, based on an instrument developed at Michigan Technological University. The primary goal was to build an accurate instrument at the lowest possible cost. The instrument determines ash content from measurements of x-ray backscatter, iron Ka fluorescence, and low-energy y-ray absorption. It is capable of measuring the ash content with a standard error of 1.1% ash over an analysis range of 9-21% ash and 7-22% solids. The analyzer was tested on coals from United States, Poland, Great Britain and the USSR.

Jan 1, 1992

By John E. Caffrey

Mr. William. J. Montgomery in his book "Theory and Practice on Mine Ventilation stated "Ventilation is vitally important to underground mining for three reasons: First, it sweeps all workings with a plentiful supply of air and drives to the outside the smoke, gases, and contaminated air which would be injurious to the miners; second, it dilutes and renders harmless the explosive gases emitted from the strata, thus eliminating the dangerous conditions caused by the accumulation of these gases; third, it keeps the mine air as nearly as possible of the same composition as the outside air, thus giving to the miner the healthiest possible condition in which to work...." Specific methods to achieve the above basic reasons for mine ventilation were established in the Federal Coal Mine Health and Safety Act of 1969. Sections 303(y)(1); (y)(2), and Section 317(f)(4) of the Act, which can be broadly described as entrapment features, are controversial and debatable in the minds of many mining engineers in their intent and method for affecting, 303(y)(1) in certain cases prohibits the use of belt haulage entries as an intake for face ventilation, This is to say that air traveling in a belt entry will be placed into the returns and not used for face ventilation, 303(y)(2) limits the velocity of the air on trolley haulage entries. The regulations, as published in the Federal Register, have set this limit at 250 feet per minute unless a higher velocity is approved by the District Manager.

Jan 1, 1972

By Gerald Zink

The work described in this paper is sponsored by the Bureau of Mines for the purpose of accelerating the drilling of roof bolt holes and reducing the quantity of materials needed to fill each hole. A high-speed small-hole drill has been fabricated and tested in the laboratory. High priority has been given to safety, reliability, and compatibility with underground coal mining practice. The combination of drag bits and erosion jets is designed for high penetration rate, long wear life, and uniform hole size in a variety of sedimentary strata. A reliable high-pressure high-speed swivel feeds water to the bit at about 4 1/min (1 gpm). The duplex hydraulic intensifier which drives the jets has a 40 kw capacity (30hhp) Results of recent full-scale laboratory testing are presented.

Jan 1, 1978

By Virginia T. McLemore

The Black Hawk district in New Mexico hosts an unusual type of deposit: arsenide five-element veins. These deposits are Ag-Co-Ni-Bi-As-bearing carbonate veins with local concentrations of U, Pb, Zn, Sb, and other elements. They are high-grade silver deposits (1000s g/t Ag), but low tonnage (<1 Mt) and difficult to find. By 1881, claims were staked and a town developed. It is estimated that >$1,500,000 was produced in 1883–1893, when Ag prices dropped due to the 1893 Ag panic. Solid Silver Mining Co. produced $600,000 from the Black Hawk mine; one car load contained $28,000 worth of silver! The town of Black Hawk grew to 125 population by November 1883. By the end of 1893, the town was vacant; nothing remains. The district was idle until 1916, and the mines operated sporadically since because of lack of available capital, water issues, and difficulty in finding ore shoots. The area is a favorite for mineral collectors. Tungsten was found in the district in 1935 in quartz veins associated with pegmatites. Metal production from 1881–1960 is estimated as 3,000 lbs Cu, 1,000 oz Au, 1,286,000 oz Ag, and 4,000 lbs Pb. In addition, 10,542 short tons of 2.7–71% WO ore and 615 short tons of fluorspar ore have been produced from the district.

Feb 1, 2025

By J. Gonzales

For this paper, blending is conceived as a linear process that takes a proportion from one stockpile or location and mixes it with another proportion from another stockpile or location, with the aim of obtaining a set of attributes in the final combination that satisfies a given quality standard. A blending class is the combination of ore attributes and grade limits that should be stockpiled in order to achieve the target quality for the process Plant. Current literature considers the number of blending classes in the Open Pit Scheduling Problem as fixed; however, this paper shows how to define specific blending classes for a given deposit so that the schedule can be solved with Sequential Linear Programming. Finally, a practical application in a Peruvian copper mine is shown, involving four ore attributes: alteration code, arsenic, oxide content and copper grade. INTRODUCTION In copper ore deposits, blending for quality has not been a typical issue as it was for coal and iron ore; however, current copper deposits in the world are becoming geologically and chemically more complex than in the past and is not uncommon to have quality standards involving up to four attributes, introducing an additional complexity to the mine scheduling process [1]. In order to solve the Open Pit Scheduling Problem with multiple ore quality constraints, two assumptions are necessary [2]: - Grade constraints are defined only by specifying an upper and lower limit; - Ore attributes in stockpiles are pre-determined, i.e., the upper and/or lower grade limits defining each stockpile are already known at the time of setting the schedule. Assuming each ore attribute is classified as high, medium or low, and there are four attributes to be controlled in the target ore quality, the number of possible blending classes would be 3^4 = 81. This number is impractical to manage in Operations, and increases the complexity at the time of running the schedule; therefore, a more efficient way of classifying ore is required. Note that in practice, one blending class can be split into more than one stockpile location due to physical capacity constraints. Therefore, the number of stockpiles could even be more than 81. BLENDING CLASSES DETERMINATION For a given set of ore grades with lower and upper limits to be achieved, one has to find all feasible ore classes such that when blended, their grades will lie within those limits.

Jan 1, 2019

By William J. Robinson

What is the cummulative rate of recovery of copper from a sulfide leach dump? This is one of the most frequently asked questions today. We, in the industry, ask it of each other when we meet; however, the technical answers may vary from "I don&apos;t know" to &apos;quite good" from people within the same company. Management also poses this question because it plays a vital role in our planning for future production. The answer is difficult because of the many variables between different operations such as physical construction of the dump, topography of the original site, characteristics of dump material, mineralization, water application, etc. Each has a bearing on the rate of recovery. OPERATIONAL DATA Our method of water distribution is unique in that each dump is drilled to allow physical injection of water into the dump. The in¬jection holes are drilled vertically, on 251 centers, from the surface of the dump. Normally, the holes are drilled 40&apos; deep and cased with 4" PVC perforated pipe.. The pipe is perforated at one-foot intervals with four V diameter holes at 901 spacing on the pipe circumference. We formerly alternated shallow holes (20&apos;-40&apos;) with deep holes (80&apos;-l80&apos;) in an effort to cover the entire dump and hasten oxidation. The shallow hole depth varied according to the compaction thickness. The deep hole depth varied according to the height of the dump and the original ground profile, We prefer to have the deep holes end 20&apos;-30&apos; above the original ground level. This generally allows us to penetrate the coarse material at the bottom of the dump. We had to discontinue the deep holes_ in order to cover more dump area in a shorter period of time to meet increased production requirements.

Jan 1, 1972

By Richard Kojo Gabah

Western mining companies are entering an African critical minerals market where access is harder to secure, risk is being priced more sharply, and execution advantages are increasingly decisive. The continent holds significant reserves and production potential of cobalt, lithium, copper, graphite, manganese and rare earths critical to the energy transition, yet Chinese-aligned capital has built a structural edge in access and execution speed. Simply signing narrow offtake agreements to buy output is no longer sufficient. Western firms win when they convert quality orebodies into bankable projects by reducing aboveground risk faster than competitors through integrated infrastructure access, durable fiscal alignment, and credible local value creation. Western mining companies will break into Africa by pairing capital with partnership, building corridors enabling infrastructure and power, designing credible value addition pathways and operating in a way that is politically durable through transparency, community benefit and fiscal terms that share upside in commodity upcycles. This feature article offers a practical playbook for mining executives and investors. The core argument is straightforward. Winning in Africa requires competing on the full system around the mine. Corridors and power, processing pathways, contract durability, community benefit and regulatory execution are now decisive variables in project valuation and capital access.

Mar 1, 2026

By R. Srikanth

Dust control in high production longwalls is a major problem requiring, among other things, careful attention to the design of operating practices, and ventilation schemes. Several studies have shown that the shearer is the major source of dust on a longwall face. Support movement has not been regarded as a major source of dust in U.S. longwalls; yet under certain conditions, 31 percent of the shearer operator&apos;s dust exposure can be due to support movement. Several methods have been developed for the control of shield-generated dust. Yet the need for better methods is apparent. In this paper, the amount of airborne respirable dust generated per shield move is estimated from specially designed experiments on longwall faces. A total of ten experiments were conducted in five longwall faces in four different mines. Each experiment involved one face visit and lasted three to six hours. The contribution of shield movement to the airborne respirable dust concentration immediately downwind of the shield moved, varied between 0.12 and 1. 75 mg/m3 in the five longwall faces. The mass of airborne respirable dust generated by shield movement was found to vary between 39 and 386 milligrams per shield move. The results from this study reveal that control of dust from longwall shields requires a combination of approaches involving alternative operating practices, reducing shield dust generation rate, increasing face air flow, and decreasing personnel exposure.

Jan 1, 1994

By Richard D. Begley

This paper will present the results of an analysis of several abandoned coal mine projects and includes field data for over a dozen different reclamation projects recently completed in the state of West . Virginia. The analysis was performed with the objective of summarizing and or classification of the environmental consequences with reference to the characteristics of the mining facilities (surface, underground, etc.). The analysis also addressed the itemized cost of remediation with respect to procedures, environmental concerns and time. The results of the analysis are that each abandoned coal mine site in West Virginia have/had many unique features and in most cases include a combination of environmental concerns that complicate comparisons. The study also revealed that the abandoned mine land program for mines abandoned prior to 1977 that is being financed by a tax on the production of coal, has produced many benefits for the state of West Virginia. This grant program administered by the Office of Surface Mining, has resulted in a high quality methodology of remediation that has been successful for many years in greatly minimizing and/or eliminating environmental concerns from abandoned coal mines.

Jan 1, 1997

By J. Navoyski, B. Macdonald, W. J. Helfrich, J. L. Bellanca, B. Demich

DISCLAIMER The findings and conclusions in this paper are those of the authors and do not necessarily represent the official position of the National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention. Mention of company names or products does not constitute endorsement by NIOSH. ABSTRACT Recent advances in computing, rendering, and display technologies have generated increased accessibility for virtual reality (VR). VR allows the creation of dynamic, high-fidelity environments to simulate dangerous situations, test conditions, and visualize concepts. Consequently, numerous products have been developed, but many of these are limited in scope. Therefore, National Institute for Occupational Safety and Health researchers developed a VR framework, called VR Mine, to rapidly create an underground mine for human data collection, simulation, visualization, and training. This paper describes the features of VR Mine using self-escape and proximity detection as case studies. Features include mine generation, simulated networks, proximity detection systems, and the integration and visualization of real-time ventilation models. INTRODUCTION There are many definitions of virtual reality (VR) that include various levels of immersion and features [1]. Some definitions refer to specific technologies [2], while others are limited to visualization [3]. For this paper, a more general definition of VR will be adopted. VR is defined as the collection of hardware and software that interactively engages users and stimulates their senses within a synthetic or virtual environment. From a hardware standpoint, this can include anything from a phone to a head-mounted display (HMD) to a large-scale theater as well as speakers, microphones, haptic sensors, and interaction devices. The software used to create virtual environments (VEs) generally includes a game engine, custom software components and libraries, and two-dimensional and three-dimensional graphical assets. Recent hardware and software advances have increased the fidelity and availability of VR. New and improved technologies including HMDs and high-resolution monitors and projectors can display sharper, more detailed visualizations. For example, in the past five years between the release of the Oculus Rift DK1 (2013) and the HTC Vive Pro (2018), there was a three-fold increase in resolution along with a 50% increase in the refresh rate. Furthermore, despite early claims that low-cost VR technology was readily available [4], computational power has not been sufficient to handle the large amount of data generated by these systems [5]. In the past five years, however, rendering speeds have more than doubled and memory has more than tripled [6], allowing these visualizations to be incorporated into higher-complexity and -fidelity VEs that more closely mirror the real world. Similarly, software capabilities have also significantly improved through game engine advancements and feature development. In the past several years, game engines have added and improved features such as physics, lighting, platform support (e.g. Android), and asset development integration. Some of the current leading commercial game engines are Amazon Lumberyard, CryEngine, Unreal, and Unity, but this can quickly change as is evident in the literature [7, 8].

Jan 1, 2019

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

Jan 1, 2011