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By B. Mirabile, B. Stables

Standing support is often used in conjunction with underground retreat mining. Knowledge of the load-displacement behavior of a standing support, and loading induced by the mine opening is critical to proper support selection. The NIOSH STOP database contains load-displacement laboratory test data for most commonly used standing supports. Hydraulic load cells currently used to measure in-situ loading of standing supports have exhibited leakage under load, producing irregularities within the dataset. An improved hydraulic load cell eliminates leakage and produces more consistent data. INTRODUCTION A hydraulic load cell, more commonly known by “flat jack” or JackPack, is a device installed to determine the loading characteristics of roof to floor supports. These standing or roof to floor supports include, but are not limited to: pumpable cribs, cans, wooden cribs (4-point, 9-point, etc.), metal props, wood timbers, concrete donut cribs, and other variations of these standing supports. Flat jack devices have been used previously to determine the loading of such roof to floor supports. The most commonly used load cell for standing supports is based on a design intended for pre-stressing standing supports, not load measurement. These load cells are produced in South Africa, and can be formed into several different shapes depending on the applications (Barczak). Flat Jacks are manufactured in various shapes and sizes depending on the application, common shapes are square and round that are 25.4 mm (1.0 inch) thick when collapsed as shown in Figure 1. The sheet metal that makes up the bladder is comprised of 19 gauge or 1.11125 mm (0.04375 inch) thickness, the top and bottom pieces of sheet metal are resistance seam welded around the perimeter. There are two different ports installed on one of the bladder skin corners of the flat jacks; these ports allow a fluid to fill the unit and the other port has a relief valve. The fill port is comprised of a check valve. The pressure relief valve is located in the second port; preset to 1724 kPa (250 psi), pressure relief valve will keep the load cell from bursting. Bursting of these load cells typically causes a small tear in the metal skin allowing the fluid to leak out without a large catastrophic failure. The effective inflation range of these load cells is between 25.4 mm (1.0 inch) to 254.0 mm (10.0 inches) thick. Different types of fluids can inflate these load cells but the most common and easily accessible fluid for testing applications is water. Water pressure from the mine supply line can inflate these load cells to the desired load. Depending on the pre-stressing requirements a pneumatic powered pump, hydraulic pump or hand pump may be required to inflate the load cells.

Jan 1, 2019

By Manfred Jaeger, Klaus Ertmer, Walter Dietrich, Jochen Greinacher, Wilhelm J. Kogelmann

In Europe, novel low-cost excavator-mounted Multi Tool Miner (MTM) systems, consisting of cutter head, hammer, bucket and drill attachments permit one unit to perform multiple tasks replacing several purpose-built machines. At the Weser Tunnel in Germany, cross-passages between the twin tubes were excavated in frozen ground with a remote-controlled mini-excavator equipped with a quick-change cutter head, ripper tooth and bucket. In Switzerland at the N2 interstate near Basel, W. Dietrich AG enlarged a 2-lane tunnel to three lanes with a cutter head mounted on a special excavator. Blasting and heavy hammers were not permitted due to the closeness of the “live” twin tube. At the N20 Zurich bypass, the Joint Venture of Jaeger, Frutingerand AHB excavates highway tunnels, some with extremely large cross sections, conventionally. A cutter head mounted on an excavator removes the rock shattered by blasting precisely to the pay line, thus preserving the rock’s self-supporting capacity preventing subsidence and damages to water resources and buildings on the surface under low overburden.

Jan 1, 2003

A coal mine located in southern West Virginia recently set a world record for daily low-seam coal production using a Cat automated longwall plow system. In a 24-hour period on April 10 and 11, 2014, the Pinnacle Mine longwall produced 32,411 t (35,724 st) from the Virginia Pocahontas No. 3 Seam, in a seam height of just 1.42 m (56 in.) along the 298-m (980-ft) longwall face. The Pinnacle Mine, located near the town of Pineville and owned by Cliffs Natural Resources Inc., an international mining and resource company, operates a Cat Gleithobel GH1600 Longwall Plow System. A previous record was set by this system at Pinnacle in August, 2012 when 29,423 t (32,430 st) were mined in a 24-hour period. The record was set by the same system, mining its second panel after a comprehensive rebuild was performed by Carter Machinery, the Cat Dealer in that area. The rebuild encompassed a complete rebuild of the headgate and tailgate armored face conveyor (AFC) drive, the headgate and tailgate special AFC pans, the stageloader drives and return end, the complete crusher and all gearboxes for the plow, AFC and stageloader. Carter acquired the rights to sales and aftermarket support associated with the former Bucyrus mining products, both surface and underground, in 2013. ?Supporting and rebuilding a longwall plow system was a new experience for the Carter service team,? said Chris Curfman, president of Caterpillar Global Mining Sales and Support Division. ?However, given the record production results attained by the rebuilt system at Pinnacle, it?s obvious that they are up to the challenge of supporting the underground product lines at the same high standards and quality level that they have been delivering for many years on the traditional Cat surface mining products.? Tom Bluth, president of Caterpillar Global Mining Products Division, said, ?Caterpillar congratulates the Pinnacle team for this great achievement. Without their efforts and dedication this record would not have been possible. To safely deliver that kind of output from such a thin seam is remarkable. We have been privileged to work alongside their team to demonstrate the capabilities of Cat longwall mining technology. ?

By D. L. Moellenberg

Under various state laws enacted mostly within the last 20 years, reclamation requirements and standards for hard-rock mining operations have been established virtually everywhere in the western United States. Unlike the uniform and detailed coal mine reclamation requirements under the federal Surface Mining Control and Reclamation Act ( "SMCRA" ) and state programs mode led after SMCRA, the various state law hard-rock mine reclamation requirements are based upon a variety of objectives, and therefore are subject to varying standards from state to state. While the diversity of reclamation requirements complicates the determination of what reclamation measures will be required at any particular mine, there are valid reasons for this diversity. There are dozens of different commodities mined in the United States, and mining methods are different for each commodity. Local natural conditions such as climate, precipitation, geology, hydrology, and biology vary widely across the county. Site-specific conditions also affect mining and reclamation methods. Also, factors such as economics, land use, and environmental protection issues receive different priorities in different states and communities within those states. State reclamation requirements in general provide the flexibility to consider site-specific circumstances, allowing operators to design and engineer the best reclamation measures for each mining site. To the mine developer or manager, reclamation requirements must be translated into design, operational, and closure measures for mine planning. Each of these measures must then be assigned additional costs to be factored into the economic decisions for a particular mining operation. On a broader level, reclamation costs must be factored into decisions such as where to invest in exploration and mine development. The purpose of this paper is to provide a summary of the state non-coal mine reclamation requirements in twelve western states. This summary comparison may be useful as a starting point in considering how local reclamation requirements will impact potential mining costs.

Jan 1, 1994

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 Ken J. Richards

Industries dependent on pyrometallurgical processing generally find themselves facing a common set of problems, namely, serious environmental restrictions, heavy capital requirements for new facilities and for plant modernization, the certainty of rapidly escalating fuel costs, and the uncertainty of fuel availability. To remain competitive, it has become clear to industry that a new dimension of attention must be given to assuring the maximum performance from plant facilities already in place and from those that are built in the future. In the last decade or so, in response to these needs, there has been an acceleration in the development of new pyrometallurgical process concepts. Their application, though spotty, is increasing. A common factor in this developing base of technology is the need for effective process control. Digital control is an indispensable element of meeting the challenge. We cannot make the point, however, by looking to a general survey of instrumental control of pyrometallurgical processes. Computer control is in its awkward adolescence. Its application is so new that only isolated applications can highlight the trends. For this reason, the authors have chosen to focus on the nonferrous smelting industry to illustrate the status of pyrometallurgical processing and control. We believe this approach will best meet the interests of most readers of this edition and the background of the authors.

Jan 1, 1979

By J. M. Dean

The MANpower SUPport Program (MANSUPP), a part of the Mine Management Support System (MMSS), allows an underground coal mine site user to determine manpower requirements for production support work by considering ongoing operations and current mine conditions. The objective of MANSUPP is to plan a detailed manpower structure for a mine by incorporating a production schedule, condition-modified work standards and management preferences to predict required manhours for various activities, for example, belt moves. The program is written in Quattro Pro version 3.0 (Lotus 1-2-3 compatible) utilizing the command language, macro and formula capabilities.

Jan 1, 1992

By P. R. Taylor

Batch leaching experiments have been performed to study the kinetics of galena leaching in fluosilicic acid solutions with oxidants. Variables studied included: fluosilicic acid concentration, oxidant type, oxidant concentration, particle size and leaching temperature. It was found that hydrogen peroxide was the most effective oxidant, compared to the others studied, and the effect of the oxidant concentration on the leaching behavior of galena was very significant. Also, decreasing the particle size and increasing the leaching temperature increased the extraction rate. The initial, apparent activation energy was calculated to be 11.72 kJ/mole (2.8 kcal/mole) and suggested that galena leaching in fluosilicic acid solution, with hydrogen peroxide as an oxidant, may be controlled by fluid film mass transfer initially. The reaction appears to be retarded by the formation of elemental sulfur and the sulfur oxidation becomes a major resistance to the overall leaching reaction.

Jan 1, 1992

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 M. Wason

An Ore bed magnetic liner element is made of permanent ceramic magnets embedded in a rubber molding. (See figure 1) They are difficult and expensive to manufacture correctly. Therefore, the lining for a complete mill is expensive, as high as 400% more than conventional rubber liners. The magnets are not very resistant to impact as they are very brittle. Mills of 12 feet or more can use only I inch balls; mills under 12 feet can use balls of 1-1/2 inches. These liners are therefore used in regrind applications with small balls or in secondary pebble mills. Rubber liners for these applications last a long time, so if life was the only consideration, the pay back for these liners would be longer than the life of the mine. The Ore bed liner and its bed of ball chips or magnetic ore is relatively thin and the surface of this bed has a high coefficient of friction. The liners are made so that opposing poles are situated next to each other and that the mill shell and the bed of ore or ball chips completes the magnetic circuit. (See figure 2) The combinations of these properties results in a very efficient liner. Due to the low profile of this bed, there is no material that is lifted too high, so we have a very compact charge with very high attrition, good for fine grinding. These liners have shown a 10% ball consumption reduction and a 10% lower power draw for the same capacity. Due to the magnetic orientation, the bed is formed in a wave shape along the lines of magnetic force. Tests conducted at a copper mine in the southwest United States have confirmed these findings. The mills where the liners were tested are 10.5 feet by 16 feet Hardinge regrind mills operating as overflow ball mills.

Jan 1, 1999

By B. E. Davis, D. A. Stanley, C. E. Jordan

A prototype expert advisor was developed by the U.S. Bureau of Mines to systematically offer advice on the control of a Florida phosphate operation. The PC based system receives input from remote sensors for circuit parameters such as feed rate, reagent addition, and pH and from operator entered information such as the quality of the concentrate and tailings in each of the coarse, fine, and amine flotation circuits. The computer evaluates the information using rules obtained from industry representatives and Bureau flotation experts. Recommended actions and questions are displayed to quickly guide the operator to a problem within the flotation circuit and suggest a solution. This process control system could provide more uniformity among the flotation operators and also serve as a trainer for new operators. In addition, it represents a step toward fully automated systems for phosphate flotation.

Jan 1, 1990

By Michael A. Trevits

The National Institute for Occupational Safety and Health (NIOSH) in partnership with Strata Products tested the sealing capability of Ventstop®? as part of an ongoing mine fire control and suppression research program. Ventstop®? is a multi-purpose, inflatable device that is produced by Minvent Solutions and is available world wide for use in the metal and nonmetal mining industry. Ventstop®? is also used in the Australian coal industry as a temporary ventilation control device. The device can be quickly deployed, is reusable and can be placed in horizontal and vertical mine voids to control dust, fumes and smoke. Deployment, multi-day inflation and air leakage tests were conducted at the NIOSH Lake Lynn Laboratory to determine the capability and limitations of Ventstop®? in a simulated coal mine setting. During the tests, Ventstop®? was also subjected to low level forces of a nearby methane gas ignition. It is thought that Ventstop®? could be used by the US coal mining industry to temporarily close an underground mine area in response to a fire or spontaneous combustion heating event, to temporarily redirect mine ventilation during longwall equipment moves or during stopping construction. This paper describes this inflatable temporary mine sealing technology and presents the results of the NIOSH tests.

Jan 1, 2009

By Ralbern H. Murray

Typical First Year Selling Price Strip Mined Western Sub-Bituminous Coal Based [Fixed Capital (1) $600 MM Construction Loan Interest $100 Working Capital $ 30 Start-up Costs $ 30 Total Capital Requirement $760 MM Annual Costs (First Year) $M/Year Coal (2) 443,550 Operating Costs(3) 53,000 Depreciation(4) 36,500 Interest(5) 45,220 After Tax Profit(6) 34, 200 Federal Income Tax (48% Rate) 31, 570 Gross Revenue Required 245,040 (Less) By-Product Sales (18, 000) Net Revenue Required 227, 040]

Jan 1, 1975

By K. Lapakko

Kinetic tests results are influenced by methodological variables, including test duration and mine waste particle size. Some samples tested produced neutral drainage in kinetic tests for more than two years prior to drainage acidification. The potential for long "lag times" can be assessed based on the mine waste mineralogy. The lag time duration can be estimated using this mineralogy in conjunction with dissolution rates observed in the kinetic tests. The influence of particle size on the drainage quality is dependent on the variation of the availability of acid-producing and acid-neutralizing minerals with particle size.

Jan 1, 1998

By Pieter-Jan Kleiterp

Highwall mining is a mining method to extract coal from a final boundary in opencut mining, trench mining or contour mining. This boundary may have been reached because of economic constraints (economic strip limit) or geographic constraints, such as spoil heaps and rivers. Coal is mined from visible, horizontal, or near-horizontal coal seams by making rectangular, parallel, unsupported drives with an unmanned cutterhead and coal transport system. This is controlled from a mining unit, or launch frame, positioned outside the drive, in front of the highwall. Removal of overburden is not required or is limited to small quantities only.

Jan 1, 2010

By R. Herrera-Urbina, D. W. Fuerstenau

A large number and a wide variety of chemical reagents are used in flotation processes for wettability and Eh control, particle agglomeration/dispersion and bubble stability. A historical account of the use of flotation reagents through the years since flotation was introduced as a viable and economic process for the concentration of sulfide minerals is given and a review of old and modern postulates of their interaction with minerals is presented. Although the results of surface and colloid chemistry studies with well characterized mineral/flotation reagent systems have advanced our understanding of the role played by these chemicals in the flotation process, many questions remain unanswered. Moreover, new flotation reagents are needed to solve the challenge posed by the treatment of problematic-type ores and fuel deposits that have increasingly become the source of our raw and energy materials. Because of the depletion of high-grade and relatively easy-to-process ores, flotation scientists and engineers are confronted with finding more specific and selective flotation chemicals to effectively and economically concentrate minerals. The development of new flotation reagents is vital for cleaning fine coal and processing polysulfide, polymetallic ores, and mixed oxide/sulfide ores.

Jan 1, 1989

By B. W. Firth

Increasing depth in vertical mine shafts penalises conventional hoists in at least four distinct ways: rope weight becomes limiting; travel time increases; the obstruction of ventilation becomes more serious; and with friction drives, rope wear due to torque is aggravated. Travel speed is limited by instability of poorly sprung conveyances on inaccurately aligned flexible rails, and also by the cost of installed power to meet an inherently peaky demand. These problems call for a review of existing designs, firstly in respect of the furniture (Buntons and guides) obstructing the air flow, and secondly in regard to the hoist running in the shaft.

Jan 1, 1969

By Corale L. Brierley

Bacteria, algae and fungi react to heavy metals in their environment by immobilizing, mobilizing and/or transforming metals. Microorganisms carry out these changes by (1) precipitating metals outside of the microbial cell, (2) binding and complexing metals to the outside of the microbial cell's protective coating, (3) accumulating metals inside of the microbial cell, or (4) transforming metals by oxidation, reduction, methylation or demethylation. Most of these mechanisms are operative in constructed aerobic and anaerobic wetlands for metal's remediation. Several more advanced biotechnologies for metal's removal from aqueous streams have been introduced, but have not been widely accepted commercially.

Jan 1, 1995

By Preston McGrain

Geologic maps are indispensable tools in the modern search for mineral and fossil-fuel resources. They are the first essential step in understanding the lithologic nature and structure of rock units that form the land surface and that lie beneath it. They provide the basic foundation for planning mineral resource exploration programs and form the superstructure from which subsurface investigations are projected. In view of the economic application of such maps, the Commonwealth of Kentucky and the Federal Government entered a formal agreement in 1960 to map Kentucky geologically on a scale of 1:24, 000, or one inch map distance equals 2,000 feet on the ground. A 7. 5-minute quadrangle would comprise the unit map area. A resolution which urged the preparation of a new geological map of the entire State was passed by the Kentucky Society of Professional Engineers in February 1959, and was presented to the Governor of Kentucky, the Legislative Research Commission, Kentucky Department of Economic Development (now Department of Commerce), Kentucky Chamber of Commerce, and Kentucky Geological Survey with a request for support and action. The request was subsequently endorsed and actively supported by numerous civic and professional societies as well as representatives of various facets of Kentucky government, commerce, and industry. Monies to initiate the program were appropriated by the next session of Kentucky legislature; this appropriation was matched by federal funds (Hagan, 1961). Kentucky's state-wide topographic mapping project was completed in 1956, just four years prior to starting the geologic mapping program. The recently completed modern 7. 5-minute, 1:24,000 topographic maps made ideal bases for plotting areal geology. Had they not been available, it is doubtful if a geo- logic mapping program so large and comprehensive could have been undertaken.

Jan 1, 1966

By Terry McNulty

There are many potential pitfalls in the commercialization of innovative technology. The failures often are remembered longer than the successes, thereby serving as deterrents to subsequent attempts. The mineral industry's future depends on effective innovation. So it is essential that the causes of failure are understood. Innovation can be examined equally well in the context of geophysics, geology or mining. However the author's experience has been in mineral processing and chemical engineering. So the following discussion is limited to processes and/or plants for producing mineral concentrates, metals or inorganic chemicals. More of what follows has to do with underachievement or failure than success. But this article demonstrates that there is a strong element of predictability in the former. Furthermore, it is a credit to the minerals industry and to the engineering profession that a very high percentage of projects succeed in achieving design capacity and forecast operating costs. Innovation means the introduction of something new. In this article, the words "innovative technology" are used broadly. They include new processes and novel combinations of established unit operations, as well as novel types of processing equipment or largest-ever equipment models. The discussion of project outcomes is based on personal experience or on published information. Citations are given for technical publications that provide either project information or insights into the methodology used to analyze project performance. However, specific projects have not been identified due to the rather negative connotations of some of the conclusions drawn about the less favorable outcomes.

Jan 1, 1998