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By John H. Clark

This paper outlines new technological improvements in underground trackless equipment for the metal mining industry with emphasis on maintenance related developments for Load Haul Dump machines. Also new developments on other types of equipment are covered including drills, road headers and electric LHD's.

Jan 1, 1983

By Drew Hobert, John Nielson, Erich Dohm

Metallurgical coal is an essential component for the blast furnace-basic oxygen furnace (BF-BOF) steelmaking process, which accounts for roughly 70% of total global steel production. To meet the growing demand for metallurgical coal, Arch Resources identified the potential to recover low- ash coal from ultra-fines discarded prior to the deslime flotation circuit across their portfolio of operations. Historically, many flotation circuits were designed to discard this ultra-fine coal due to high clay content and technological barriers to cost-effectively upgrade and dewater the coal to a saleable product. Recent advancements in high-intensity flotation technology, including the Eriez StackCell, have enabled coal producers to recover ultra-fine coal while minimizing capital and operating costs. In July 2023, Arch Resources commissioned the first full-scale ultra-fines recovery circuit utilizing StackCell high-intensity flotation technology at the Leer Mining Complex. This paper reviews the approach utilized to develop the flotation process design, learnings from the commissioning and ramp-up period, and performance data through the first year of operation.

Feb 1, 2025

By J. A. MacLellan

It is the hope of the author that this paper, largely a compilation of observations and opinions built up over 20 years of experience in cold and remote areas may be of some help to others in designing better plants for the future in the north. The north is not as difficult to operate in as the better story tellers make it appear to be. ()n the other hand for 6 months of the year the cold is always there, and it seems to be waiting for someone to make a mistake. The simplest things can shut a multi-million dollar plant down at -4n' F with a 4n M.P.H, wind. It only takes one man door improperly latched to freeze up all the pumps on the bottom floor. Someone can poke a one inch hole in an outside wall in July and six months later while you are having Christmas dinner, a watchman will call up to report that the whole plant is flooded because the main water line just froze up and burst. Basic things to remember in plant design for cold and remote areas are: everything in these areas is more expensive due to long and difficult supply lines. Fuel is expensive and would be a major cost item even if it were not expensive, due to the extended periods of low temperatures. Building volumes should therefore he kept to an acceptable minimum. Service areas on the other hand must he adequate, because maintenance generally has to be conducted inside in a heated area. Supply vehicles for instance have to get completely inside the building to unload. If you try to unload a supply vehicle with the door open at -50° F, you won't be able to find the vehicle for fog and if you take more than 5 minutes half the water lines in the plant will freeze up. People in a remote area are expensive. The capital investment per employee may be as high as $30,000; with fringe benefits per annum costs of an employee will he as high as 812,000 per year regardless of basic wage rate. It

Jan 1, 1971

By E Mutaz, M Bahaaddini, D J. Williams, M Serati

The contribution of the mining industry to the global economy has reached (and gone beyond) $1,800 billion in recent years that necessitates (more than before) the need to ensure workability, viability, health, and safety of mine sites and workers to meet the ever-increasing global demand for mineral resources. Amongst the many challenges facing the excavation industries, rockburst and spalling failures in deep mines in hard and brittle rock formations are yet happening that are still deemed as unsolved problems. During unconfined compressive testing of brittle rocks, microcracks initiate at approximately 0.3–0.5 of the peak strength (which is commonly known as the Crack Initiation stress level) mainly in the direction of the major principal stress, then grow unstably and coalesce to form macro fractures at approximately 0.7–0.8 of the peak load at a so-called Crack Damage stress threshold. From a stress-strain perspective, the crack damage stress threshold () is associated with the reversal point of the volumetric strain, which is also proved to be strongly affected by the intermediate principal stress. This paper extends the previous studies on the impact of true triaxial loading conditions on the CD stress level in high porosity rocks, and introduce a new Crack Mode-Changing Stress (CMCS) defined as the minimum principal stress required to change rock fracturing from splitting to a sliding failure mode. A large number of experiments on sandstone specimens were carried out at different true triaxial loading conditions and the effect of principal stresses on the CI and CD as well as CMCS were studied. The results show that not only the intermediate principal stress, but also the minor principal stress can significantly affect the CD and CMCS thresholds.

Apr 26, 2022

By B. Tolwinski

Long-Term Open Pit Scheduler or L-TOPS is a new software package for evaluating, planning, and design of open pit mines. L-TOPS transforms geological, economic, and technical information about a mineral deposit into a detailed mining schedule that maximizes economic efficiency without neglecting the practical requirements of mining operations. L-TOPS has been customized for integration with Placer Dome Inc.'s existing in-house resource/reserve optimization software to function as a primary tool for property acquisition studies and for the designing of mines for feasibility studies. This pa-per presents an overview of L-TOPS and reports on its application to Placer Pacific's (Placer Dome's Australian affiliate) Mt. Rawdon project.

Jan 1, 1996

By Yi Luo, Hua Jiang

A roof bolting drilling operation in an underground coal mine can expose the operator to a high concentration of respirable coal and crystalline silica dusts (smaller than 10 µm). Overexposure of high-level quartz dust for a roof bolter operator can lead to the development of silicosis in as little as three years [1]. This study proposes a drilling control algorithm for the bolt hole drilling process. This algorithm can be integrated into a current drilling control system on the roof bolter machinery and is expected to reduce the generation of respirable dust while enhancing the energy efficiency of the roof bolter machine. In addition, the drilling efficiency and bit condition can be evaluated while drilling based on the real-time feedback parameters. This capability enables the algorithm to ensure the drilling is performed under a relatively high energy efficiency with less respirable dust generation and to avoid drilling with an excessively worn bit that can cause bit clogging or steel buckling failure.

By S. S. Peng

Since the introduction of shield supports in 1975, safety and production in U.S. longwall faces have improved considerably. Many faces had a daily production of up to 8,000-10,000 tons and productivity reached 600 tons per man-shift. But a longwall face requires expensive equipment which slows down the growth rate of the percentage of longwall production. Among the equipment cost the shield support accounts for 50-60%, a very large proportion. Therefore, it will have a large impact on the growth of longwall mining in the U.S. to reduce the support cost (1).

Jan 1, 1988

By Bobby P. Faulkner

Allis-Chalmers has combined a new heat transfer device, called the ROLLER GRATE, with a unique processing scheme, resulting in the ROLLER GRATE Oil Shale Processing System of Allis-Chalmers. In order to test both the process and the equipment, a batch Process Development Unit (PDU) ROLLER GRATE retort was designed and built. This unit vas designed with the flexibility to process shale over a wide range of test conditions in order to demonstrate the attributes of the oil-shale processing system. Instrumentation on the PDU and extensive sampling of the effluent streams permitted the PDU test data to be used in the design and scale-up of the process. Over 30 tests have been conducted with Colorado shale, and over 25 tests have been run with an Indiana shale. In addition, rests have been run with California and Utah tar sands.

Jan 1, 1983

By J. L. Mehaffey

A variety of chemicals offered by Armak were evaluated as dewatering aids for aqueous slurries of silica sand, sparsand and feldspar; an established commercial dewatering aid was used as a control. A number of Armak's potential dewatering aids yielded lower moisture retention values than did the commercial product on all of the mineral samples. In addition to the chemical dewatering evaluations, some of the mechanisms involved in the removal of water from these mineral samples were examined.

Jan 1, 1983

By T. A. Gray

The environmental liabilities of coal waste disposal sites can have a major impact on a mining project's economic viability. Developing a waste disposal site is no longer simply an exercise in completing paperwork to obtain a permit, with the proliferation of environmental regulations in recent years, managing disposal sites now requires design creativity, short term and long term planning and detailed monitoring to maximize the benefits to the mining company. Operating costs and future capital costs for expansion of existing sites, new site development and regulatory compliance should be reviewed periodically and considered in the overall management plan. This paper discusses various management methods that are being employed in the industry to improve waste disposal operations both environmentally and profitably.

Jan 1, 1994

By T. Dombrowski

Acid-activated montmorillonite is used worldwide as a catalyst and as a sorbent for the enhancement and purification of petroleum products as well as vegetable and animal-based fats. The solid-acid character of the activated montmorillonite is imparted by the manufacturing process, giving it unique properties that are exploited in these industries. Several international companies and a multitude of local clay producers are focusing on improving the efficiency of their standard and specialized products. This paper will describe the use of acid-activated montmorillonite in traditional sorbent applications, as a solid acid catalyst, and other new uses.

Jan 1, 1997

By M. Bleeck

Calcium carbonate (CaCO3) is one of the most ubiquitous and versatile minerals found in the earth's crust. Its availability, attractive physical properties and relatively low processing cost make CaCO3 the most widely used filler material today. It is mined in three different forms - chalk, limestone and marble. Each physical form of CaCO3 has different qualities due to differences in postdepositional geology. But the chemical composition remains the same, with CaCO3 an inert component of the finished product. In the past, the paper industry largely left CaCO3 by the wayside, as it cannot withstand the acid-based papermaking process. But conversion to an alkaline system by many US mills changed this picture. Carbonate suppliers have put time and effort into research and development, demolishing barriers and creating new possibilities for what is a simple, natural product. By controlling particle size, size distribution and particle charge, the industry uses ground calcium carbonate (GCC) as a performance enhancer and as an extender for more expensive ingredients. It is estimated that the United States uses 3.6 to 4.1 Mt/a (4 to 4.5 million stpy) of CaCO3. Consolidations and mergers are taking place in the industry. Of the 12 major GCC producers in operation nine years ago, seven are left. Mineral Technology (US) is the dominant precipitated calcium carbonate (PCC) producer with more than 50 satellite plants worldwide. Other producers include Georgia Marble (French); Franklin Industries (US); OMYA (Swiss); J.M. Huber (US); ECC (English); and Filler Products (US). Global Stone PenRoc (Canada) is the only newcomer. In addition to this group, there are three small producers left in North America, each with a capacity of less than 100 kt/ a (.110,000 stpy). The trade organization operating as the Pulverized Limestone Division of the National Stone Association renamed itself the Pulverized Mineral Division, to increase its membership pool. The US paper industry is a predominant GCC con¬sumer, using approximately 800 kt/a (882,000 stpy) at an approximate cost of $130/t ($1.43/st). European paper mills pioneered alkaline papermaking. In the early 1960s, they began using GCC as filler and soon thereafter added GCC to their coating formulations. A decade later, the North American paper industry followed suit. The conversion from acid to alkaline paper production benefits the economic and performance aspects of the industry. Less pulp is needed, paper machine maintenance and effluent treatment costs are reduced, and sheet strength, opacity and brightness are increased. Perhaps most important to the reader, the sheet is desensitized to ultraviolet light, extending the paper's archival ability. CaCO3 can provide the papermaker with additional control of his paper. For example, PCC has long supplied the tobacco industry with a means to slow down the burning rate of cigarettes. Due to enhanced performance with regard to bulk and opacity, filler PCC use has risen to 1,500 kt/a (1,650 stpy) in the United States, at an approximate price of $130/t ($143/st). The majority is produced onsite at the paper mill, using "satellite plants." This concept reduces freight cost because only quicklime (CaO) is shipped to the mill, not CaCO3 slurry. The future of CaCO3 is encouraging. The amount of natural ground CaCO3 used is expected to double by the year 2005 to approximately 8 Mt (8.8 million st) worldwide. Acid papermaking practices will feel an increasing pressure to convert to an alkaline process as larger volumes of GCC containing paper enter the recycling market. CaCO3 reserves are plentiful. They will supply the ever growing demand for increasingly sophisticated paper. The plastics industry is supplied with almost 900 kt/ a (990,000 stpy) GCC at an annual growth rate of 4% to 5%. The price of a functional, inorganic filler, surface modified for the plastics industry, has an average selling price of $220/t ($243/st). GCC represents the most common filler, creating a product with higher gloss, better dielectric properties, impact resistance, weatherability and shrinkage control. CaCO3-filled plastics surround us - auto hubcaps and dashboards, shower enclosures, floor tiles, wire coatings, microwave dishes and Tupperware. The caulking and sealant industry is an enormous GCC user, with annual consumption requiring 1.13 Mt (1.2 million st) at about $44/t ($48.50/ st). Caulking and sealant may be highly filled with GCC yet undergo no adverse flow effects, with a narrow particle-size-distribution filler decreasing the binder demand. The CaCO3 industry, as well as the carpet industry, are more or less tied to the growth rates of the construction industry. It is estimated that the carpet industry uses some 680 kt/a (750,000 stpy) of GCC at about $25/t ($27.50/st). The paint industry uses approximately 300 kt/a (331,000 stpy) at a 1 % to 1.5% annual growth rate. Here, too, GCC is the dominant filler. It is used to enhance flow characteristics and color uniformity. It also extends costly titanium dioxide, creates sheen and controls roughness, hardness and tack. More CaCO3 should be used in the future as industry shifts from solvent-free or water-based formulations that can accommodate higher GCC volumes. CaCO3 is not imported or exported in any great quantity. Most areas have reserves of their own and the selling price is relatively low. Even so, quality varies from deposit to deposit. As our needs become morespecific, it remains a challenge to provide varying industries with a fitting product.

Jan 1, 1998

By Raj K. Rajamani, Samira Rashidi

High pressure grinding rolls have been utilized in various operations during the past four decades, simply due to their inherent mode of breakage that offers metallurgical benefits with pronounced energy reduction. For every new application, wear and in particular roll surface wear protection has always been the focal point of HPGR trade-off studies. Wear remains an important issue throughout a mine’s life given inevitable variations in the ore deposits properties. Hence, the capability of continuous scanning of rolls provides ample information about any deviations in the design values as well as their effect on the wear pattern. In part I of this manuscript, we present the feasibility of in-line scanning of roll surface in a 200 × 100 mm lab-scale HPGR. First, the in-line scanning was developed in a mock-up roll and then the scanner was moved to the laboratory-scale HPGR. We present the choice of scanners and the methods adopted to achieve high-level accuracy of determining wear. Even though we planned for micron-level precision of scanning, the inherent variability in shaft rotation was higher than the variability in the roll diameter due to wear. The hundred-kilogram mass processed in the HPGR was not sufficient to create enough wear that is discernible to the in-line scanner. Yet, the method tested is a promising avenue for inline scanning of HPGR rolls.

By Robert Bissonette, Samir Sbai

A critical component of implementing autonomous systems is the ability to use information from a robust sensory and information system to make sound, predictable, and repeatable decisions to assure safety. This means that any such system would need to evaluate what objects (people, equipment, boulders, etc.) of interest exist in that environment (with relevant data about identity, trajectory, characteristics, etc.), project a future continuum of those objects (including considerations for variabilities), and make control intervention choices to minimize risk due to exposures in the present operational area. The components of an overall system would include: a) sensor and data fusion, b) probability projection of future states, c) generation and evaluation of alternate futures, and d) implementation of best course of action to reduce risk. The National Institute for Occupational Safety and Health (NIOSH) Spokane Mining Research Division (SMRD) is studying this framework for applications for autonomous mining equipment. This paper focuses on using information from the sensor fusion engine to generate a continuous projection of future and alternate states (b and c above) incorporating the factors of confidence, accuracy, tolerance, and other variabilities. We refer to this as Machine Situational Awareness (MSA).

Jun 25, 2023

By Rollin A. Slater

The bulk materials handling industry has served silently for years as the skeleton structure and often the central system of nerves and nourishment for the body of basic production industries. During the past two decades, this body has undergone substantial growth and mutation to meet the surging demands of our national economy for more and better products. The steel industry has been prominent in this phenomena and plants of the sixties are as unlike the second war vintage as our current crop of basketball players differ from their fathers. Steel has kept pace with spiralling demand by innovation which has resulted in new processes and improved designs which generally yield greater production from fewer units. The supporting industry of materials handling has likewise improved its techniques and currently has a new stronger generation of equipment to perform its necessary supporting function. It has been my fortunate experience to have been instrumental in the creative stages of several new steel mills which are currently in conceptual design or actual construction. Drawing upon exerpts from this experience, this paper will describe a basic approach to the selection and application of modern bulk materials handling systems to an entirely new steel plant. Specific details of past work are not available for publication, therefore, the plant described herein is a composite of ideas and will be the new plant of the Hypothetical Steel Corporation which will be located on the lower shores of the Great Lakes.

Jan 1, 1967

By B. K. Mishra

Power draw of the mill has been accepted as an indicator of the performance of the mill, yet the problem of predicting power under a given set of mill operating conditions still remains to be solved. In the literature, this problem of predicting power is attributed to a lack of knowledge with regard to the motion of the charge. Here a DEM based model is used to analyze the motion of the charge. The resulting information is used to predict the power draw of the mill. A 16-ft diameter mill is simulated. A factorial design study of the variables-mill speed, lifter configuration and ball size distribution-as independent variables is taken up. The power draw as a response variable is analyzed to establish the best operating condition of the mill.

Jan 1, 1993

By Joe B. Rosenbaum

Fine-sized mineral wastes discarded by ore milling plants require stabilization to prevent air and water pollution. Methods devised for achieving this stabilization include physical, chemical vegetative, and combination procedures. Although vegetative reclamation is preferred to physical and chemical stabilization, it is difficult to achieve because the wastes are sterile, contain deleterious inorganic salts, and lack the essential nutrients and physical characteristics required for sustaining vegetative growth. Nevertheless, recent research has developed methods for producing vegetative growth on all but excessively acidic, basic, or saline tailings at costs ranging from $100 to $650 per acre. This report summarizes effective procedures developed for vegetating average tailings, the cost differential between the various methods, and suggests procedures that may be applicable for achieving stabilization of pyrite-containing wastes that may oxidize and become excessively acidic. The use of buried layers of sewage sludge to prevent this acidification is discussed.

Jan 1, 1972

By B. J. Sauer

Misapplication of AC induction motors for mine crusher and mill applications has long been a frustration for both the driven equipment supplier and the mine operator. Proper selection of AC induction motors is critical to providing efficient production. This paper focuses on the selection of AC induction motors for gyratory crusher, cone crusher, and grinding mill applications. The criteria for motor selection includes: proper enclosure, driven equipment torque requirements, bearing life, temperature rise, starting requirements, ambient temperature, altitude and accessory requirements.

Jan 1, 1999

By P. M. Soupios

An integrated suite of environmental methods was used to characterize the hydrogeological, geological and tectonic regimes of the study area, to determine the geometry of the landfill (depth and spatial extent of electrically conductive anomalies), to define the anisotropy caused by bedrock fabric fractures and to locate potential zones of electrically conductive contamination. The study area which covers an area of about 0.08 Km2 is a municipal solid waste site (MSW), located 20Km West of Herakleion in the central part of Crete (S. Greece). The landfill is located in a northwest oriented valley with highlands to the northeast and southwest. The combination of geophysical methods and chemical analysis are commonly implemented for characterization and management of land-fills. At the particular site, geophysical methods were focused on studying the electrical insolating properties of the materials, electrical con-ducting properties of fluids (leachates) and electromagnetic properties of the disturbed regolith materials in the burial zones. Three different types of geophysical surveys were performed: 1) 2D electrical tomography (ERT), 2) electro-magnetic measurements using very low frequencies (VLF) and 3) electromagnetic conductivity (EM31). Furthermore, in order to calibrate the geophysical methods dielectric spectrometry measurements are conducted. To evaluate the environmental degradation of the area, soil and liquids samples were collected.

Jan 1, 2005

By Steven W. Hunt, Gregory C. Baker, Glen J. Rorison

Microtunneling methods were utilized beneath pile-supported clarifier basins to replace settlement damaged sludge drain lines at the Jones Island Wastewater Treatment Plant in Milwaukee, Wisconsin. To minimize the risk of blockage and expensive recovery of a microtunnel boring machine against pipe piles or construction debris, a Soltau RVS 80 was utilized. This machine allowed the alignment to be initially bored with guided 114-mm diameter rods to ensure proper alignment and lack of obstructions. Casing pipe was then installed by jacking 1-m long, 305-mm diameterclay pipe along the rods and behind an auger head. This case history also discusses how 2.4-m diameter precast concrete pipe was used as a one-pass sinking caisson for workshafts and new cleanout manholes.

Jan 1, 2001