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Traction of mining vehicles is well understood for a variety of unfrozen road surfaces, allowing optimal design of mine access and haulage roads. However, no such characterizations exist for the frozen or partially frozen surfaces typically encountered in Northern regions. Recent work by U. S. Army researchers suggests methods for characterizing roadway traction for any vehicle on the basis of test measurements made with a standard test vehicle. Such a test vehicle was designed, and several sets of test data were recorded at the onset of winter in Fairbanks, Alaska. This work suggests methods for future research and possibilities for the use of such research in designing drive systems, tires, and mine roads for Arctic and sub-Arctic mines.

Jan 1, 1995

By J. P. Bunch

As the number of environmental laws continues to steadily increase and the economic penalties for contamination problems become more severe, environmental management represents an important management function within today's U. S. mining industry. The economic impact to a mining company for contamination is not only realized in legal fees and fines but also in the cost of doing normal business. For example, a mining company with contaminated property applying for a loan may be refused because of a lending institution's reluctance to finance due to liability concerns. Or, an insurance company may decide to greatly increase its annual premiums because of existing or potential contamination problems. One of the main duties of the environmental manager is to seek ways to reduce these types of problems by eliminating contamination or by knowing what problems exist and designing corrective measures to prevent the situation from worsening.

Jan 1, 1990

By Wilhelm J. Kogelmann

The quest for U.S. energy independence will result in a major increase in underground mining operations. It will necessitate the rapid excavation of development drifts, entries and slopes to exploit underground deposits of energy resources such as coal, uranium and oil shale. Most of this development work will be done in soft and medium hard rock up to an unconfined compressive strength of approximately 20, 000 psi. OBSTACLES TO RAPID TUNNEL EXCAVATION Labor In the U. S. coal mining industry, the underground productivity in tons per man-day declined from 15. 61 in 1969 to 11. 00 in 1973 which is a startling 30% decline. While productivity declines, the cost of labor and supplies continues to rise. Ralph E. Bailey of Consolidation Coal Company recently stated four reasons for the decline of productivity: A shortage of experienced miners, enactment of the Federal Coal Mine Health and Safety Act effective April 1970, major changes in union work rules in 1968, and a deterioration in the attitude of the work force (1). Because there is already a great shortage of skilled miners, the situation will get worse when large new mines for oil shale, coal and uranium open in sparsely populated areas in the Western United States. Only the large scale use of easy to operate tunneling machines can increase productivity and lower the cost of excavation.

Jan 1, 1974

By B. H. Kim, S. J. Schatzel, K. M. Ajayi, G. S. Esterhuizen, D. W. H. Su, Z. Khademian

The stability of shale gas wells drilled through current and future coal reserves can be compromised by ground deformations due to nearby longwall mining. Depending on the longwall-induced rockmass permeability, the high-pressure explosive gas from the damaged well may reach mine workings and overwhelm the mine ventilation systems. This study uses geomechanical models to estimate the rockmass permeability induced by mining. A two-panel longwall model of a deep, 341-m-cover mining site in southwestern Pennsylvania is constructed in 3DEC to explicitly model the rockmass by a Discrete Fracture Network (DFN) technique. Stress-induced fracture apertures and permeabilities are calculated across the model and are validated against permeability measurements. A Fracture Flow Code (FFC) is developed to use these results to predict potential inflow to the mine should a gas well breach occur. One hundred DFN realizations are simulated, and the results show that for a gas pressure of 2.4 MPa, the average of the predicted inflow rates to this deep-cover mine is 0.03 m3 /s, significantly lower than the average inflow of 0.92 m3 /s for a shallow-cover mine (145 m deep) studied in the previous work (Khademian, et al. 2021). The result can help assess the potential hazards of a shale gas well breach for mine safety and evaluate the ventilation requirements to mitigate the risk

Mar 2, 2022

By J. J. Antony

As the first wave of precious metal heap leach closures and reclamation projects occur, a number of companies are being hit with costly surprises. While this paper refers specifically to U.S precious metal projects, it could be conceptually directed at copper leach operations and acid rock drainage (ARD) problems on an international basis. ARD is Mother Nature's version of heap leaching, only with different products and timing. Although many precious metal deposits tend to be small in comparison with some base metals systems (porphyry copper deposits), adjacent or nearby discoveries have extended the operating lives of numerous precious metal mines. Now, depleted reserves, several years of relatively depressed precious metals prices and some properties with technical difficulties have resulted in numerous mine closures. As a result, our industry is getting a diverse and comprehensive initial look at mine closure and final reclamation. The situation has been further complicated by the evolutionary trend in regulations and their enforcement and increasing public and political awareness of all environmental issues. Concurrent (proactive) vs. deferred (reactive) reclamation and a realistic early appraisal of ultimate reclamation and closure requirements, not just regulatory compliance, need to be a part of project design. The U.S. and Canada are the current fertile testing grounds and have set the design, regulation and closure standards for the next wave of operations in Latin America, the CIS (?), etc.

Jan 1, 1994

By F. Dudouit, M. M. Mohkam, F. Renault

The Pannerdensch Kanaal Tunnel is part of Holland’s Betuweroute high speed freight railway project linking Rotterdam to inland of Europe. It comprises of twin tunnels, 1620 m long each, with 8.6 m inner diameter. The Tunnel alignment is situated mainly in sandy formations and under high hydrostatique pressure. The over burden cover varies from relatively high to very low, sometimes much smaller than the diameter. One of the special features of the Pannerdensch Kanaal Tunnel is that, over some 250 m, the twin tunnels are to be bored in a back?lled sandpit. Some 490 000cubic meter of sand has been placed and compacted by vibro-?otation to refill the sandpit. The tunneling machine is a 9.8 m slurry shield manufactured by Herrenknecht. Tunnel lining is precast concrete consisting of seven plus one key universal segments. Other than the special feature of boring through re?lled sand, constraints such a slow overburden while crossing under Pannerdensch Kanaal and some lagoons, as well as high liquifaction potential of sandy formations, render this job very unique of the type. Fine studies were conducted in heading’s stability. And, confinement pressures were determined considering different risks of liquefaction and blowout problems. Both tubes have been successfully bored. Several sections have been monitored. The results are quite interesting and in accordance with contract technical conditions.

Jan 1, 2003

By T. W. Oshnock

Pulverized coal (PC) and other injectants can be injected into the blowpipes of a blast furnace to decrease coke requirements. Throughout the history of blast-furnace development, there have been many attempts at injecting PC. In the 1960's a more serious effort was made to improve pulverized coal injection (PCI) technology. However, because of the additional capital requirements and the projected near-term inexpensive cost of other injectants, very few PC1 systems were installed. When the second oil crisis occurred around 1979, the shortage and high cost of fuel oil caused blast-furnace operators to operate without oil injection. It was soon discovered that blast- furnace operation without oil was not as smooth or efficient. Experiments with PC1 quickly showed that coal was a good replacement for oil which resulted in the rapid application of PC1 in both Europe and Japan. As a result, PC1 technology for blast-furnace operation has progressed rapidly during the 1980's. This paper will describe the worldwide status of PCI, characteristics of different PC1 systems, the effect of PC1 on blast-furnace process parameters, and the economic effects of using PCI. Results from the USS Blast-Furnace Thermochemical Projection Model comparing the effects of different coal properties and the effects of other tuyere injectants such as oil and natural gas will also be described.

Jan 1, 1988

By Ching L. Wu, Bolek Chytrowski, Peter Frobenius, Dale Roberts

During the past few years, the first stage of the Waste Isolation Pilot Plant, (WIPP) which consists of an exploratory shaft, a ventilation shaft, shaft stations, access drifts and test rooms, has been under construction. Construction of the first stage is scheduled to be completed in the summer of 1983. The U.S. Department of Energy (DOE) is constructing the WIPP facility to demonstrate the feasibility of disposing of defense-related nuclear waste in the bedded salt deposits of the Delaware Basin near Carlsbad, N.M. The project promises to be a proving ground for underground nuclear waste storage facility design and construction. The completed underground plant will extend over an area of 647,500 m2 (160 acres), and 1,360,500 metric tons (1,500,000 tons) of salt will be excavated. The first stage of the project, the Site and Preliminary Design Validation (SPDV) Program, provides for full-scale construction of the major components of the underground facility. Shaft construction and underground development are described. Rock bolt installation is performed as required for roof control. Geotechnical instrumentation is installed to monitor the behavior of underground openings. Direct observation of the constructed shafts, shaft stations, and underground openings is expected to confirm the adequacy of the underground design and allow full-scale construction of the first U.S. underground nuclear waste storage facility to proceed.

Jan 1, 1983

By Mark S. Stagg, Michael J. Nutting, Douglas R. Barlet

Single-row bench blasts at a reduced scale in the field were used to study the effects of delay time on fragmentation. Nine shots with a spacing of 21 in. and a burden of 15 in. (S/B = 1.4) and nine shots with a spacing of 30 in. and a burden of 15 in. (S/B = 2.0) were completely screened to determine particle size distributions. Delay intervals between holes ranged from 0 to 45 msec, corresponding to effective delay intervals ranging from 0 to 36 msec per foot of burden. Each shot was instrumented with strain and pressure gages to measure in situ blast dynamics and to evaluate interactions between blastholes. Finer overall fragmentation was produced for shots with delay intervals between 1 and 17 msec per foot of burden. Only for shots within this optimum delay range was it observed that the strains induced by stress waves constructively interacted with strains induced by gas pres- sure from an earlier detonated hole. Coarsest fragmentation resulted at delay intervals less than 1 msec/ft, where stress waves from each hole were observed to interact destructively, and at delay intervals greater than 24 msec/ft, where no inter- action between holes was observed, indicating a condition that can be considered as the firing of single hole shots independently.

Jan 1, 1986

By Keith G. Wallace, Daniel J. Brunner

The traditional approach to mine ventilation planning involved making estimates of airflows, including leakage routes, and summing the corresponding pressure drops along consecutive paths in order to determine the fan pressures required. This methodology changed completely with the availability of computers. Mainframe digital computers began to be used for mine ventilation network analysis in the mid-1960's. Their use spread rapidly throughout the world in the 1970's. Mainframe machines were employed owing to the need for high speed numerical procedures and substantial storage requirements. However, during the past decade, the growing availability of low cost but powerful microcomputers has allowed the development of net- work analysis programs that can handle ventilation systems of hundreds of branches, and which can produce results within a few minutes. This paper discusses recent advances in software and hardware development specific to mine ventilation planning. Software developments include interactive data and output manipulation, graphical representation of output, internal checks on input parameters to preset ranges and subroutines which calculate the gas distribution throughout the network from known gas sources. Hardware advances have led to significant increases in memory to facilitate the analysis of large ventilation models, math co-processor chips which greatly shorten run times, and plotter hardware for graphical output displays. Recent software developments make it possible to graphically display output on printers faster than on standard plotters.

Jan 1, 1989

By G. A. Rosario, G. Peach

Twin 8.5 m diameter, 10 km long headrace tunnels under overburdens of up to 1870 m were excavated for the neelum jhelum hydroelectric project in north-eastern pakistan using two main beam gripper tunnel boring machines (tbms). Rock bursts were encountered and presented a significant danger to personnel and equipment. Micro seismic monitoring was installed to analyze rock burst characteristics and to create a database for future reference. Correlation of rock burst characteristics improved the ability to predict the likelihood, location, severity, and number of rock burst events. This paper presents the analysis of the micro seismic data

Dec 1, 2022

By Y. S. Kim, A. Bailey

A feasibility seismic refraction and reflection field survey was conducted at the U. S. Borax Company open-pit mine, Boron, California by the writers during the weekend of March 13 and 14, 1976. This field survey was carried out as a preliminary investigation primarily for the purpose of evaluating and establishing the ability of such geophysical techniques to locate and outline the subsurface openings of the old room-and-pillar mining under the present open-pit. The value of such knowledge about the old underground workings is directly related to the safe and economical operation of the open-pit mine for the company. Although mine maps of the old underground workings are available at the mine, the extent of roof and wall cavings and the present condition of the old underground openings are unknown. Owen and Suhler (2) are the first investigators who used electromagnetic methods, Pulse-Echo System, and electric resistivity measurement to solve the problem without success. A few years later, Herzig and Owen (1) attempted to solve the problem with application of earth resistivity measurement method with unfavorable results. The U. S. Borax Company carried out an extensive study for slope failure problems of the open-pit with application of dipmeter measurements. However, the slope stability study was not correlated to the old underground openings lying under the present open-pit (3).

Jan 1, 1977

In conjunction with steady increases in production levels, long-wall operators have applied greater quantities of ventilating air to control respirable dust and methane gas. As a result, air velocities greater than 7.6 m/s (1500 fpm) have been measured on longwall faces. Operators have expressed concern over the potential entrainment of respirable dust at these high-velocities, especially during shield advance as dust falls from the shield canopy directly into theair stream. Laboratory tests to simulate dust liberation by shield movement were conducted at the Pittsburgh Research Laboratory of NIOSH in a wind tunnel designed to study dust entrainment in high-velocity airstreams. Dust was introduced into the tunnel to determine dust concentration as it relates to entrainment, dilution, air velocity, and particle adhesion. Airborne dust samples were obtained by iso-kinetic sampling using BGI cyclones to quantify respirable dust concentration at the various air velocities. Laboratory tests were con-ducted at velocities ranging from 2.0 to 10.1 m/s (400 to 2000 fpm),and significant differences in airborne respirable dust levels were measured. This research is being conducted to provide fundamental information on the entrainment characteristics of respirable dust at high air velocities, which will subsequently lead to solutions for shield dust control. A discussion of the test procedures and results are presented.

Jan 1, 2004

By Thomas R. Hightower

The Thunderbird plant was erected in Sullivan County in Indiana during 1958-1959. It was first put in operation in March of 1959. At the present time the source of the raw coal is from the Indiana No. 6 seam. The underground operation at present consists of two continuous mining units and two conventional units. The underground is all belt haulage and the first unit with which this paper is concerned is the slope belt. It is a 48-inch-wide inclined belt with 980-foot centers and a lift of 275 feet. The belt is powered with a 350 H, P, motor and has a rated capacity of 600 Tons per Hour. The belt is equipped with a Merrick Scale Company Weightometer, The raw coal moves from the belt to a 6'x12' extra heavy Allis-Chalmers Ripl-Flo equipped with 6" round-hole screens. The over product of the screen is fed into a 10'x20' long McNally- Pittsburg rotary breaker equipped with 4-l/2" round-hole screens. The oversize rock is discharged into a bin that is emptied with a refuse truck. The through-product of the breaker, along with the through-product of the Ripl-Flo, passes either directly to the McNally Giant washbox or to a 36" belt that transports it to a 1000-ton storage bin,' The change from either to the washbox or to the storage bin is made by use of a motorized gate controlled by the plant operator,

Jan 1, 1961

By Campbell J. McKenzie

Following on from the successful completion of three exploration programs and the discovery of two new inactive Seafloor Massive Sulphide (SMS) deposits within New Zealand?s Exclusive Economic Zone (EEZ), Neptune is now poised to take the next step from explorer to developer. Neptune considers that commercialization of SMS deposits represents the future of the mining industry, providing a new source of metals to the world economy, and enabling host countries to benefit from this new industry. Neptune recognizes that marine biodiversity is among the greatest treasures of New Zealand. The geological isolation, range and complexity of habitats, and a number of major ocean currents that influence New Zealand have created diverse marine communities. Neptune, recognizing both the environmental importance of marine biodiversity and the value it provides to all New Zealanders has made commitments to ensure sustainable development. There are many unanswered questions regarding how the marine environment may be affected by SMS development, however best practice environmental management is a key aspect of the Company?s approach to our activities and the code for ?Environmental Management of Marine Mining? prepared by the IMMS has played a part in this approach. Neptune has close relationships with the scientific community to ensure that appropriate environmental strategies and plans are developed in order to minimize the effects of our activities on the environment.

Jan 1, 2008

By Harry R. Price, Jerome C. Neyer

INTRODUCTION Safety must be a primary consideration in the design and construction of tunnels. Tunnel construction has historically been considered a high-risk business. During the construction of the 14.8 kilometer (9.25) mile St. Gotthard Tunnel in the Swiss Alps in the 1870s, 310 lives were lost and another 877 workers permanently disabled. In more recent days, two tunnel construction accidents in 1971, one in Michigan and one in California, claimed the lives of 38 workers. Prior to 1971, most regulations governing safety in tunnel construction were developed by the U.S. Bureau of Mines. These included a 1941 Bulletin 439, "Some Essential Safety Factors for Tunneling" and a 1968 Bulletin 644 which updated Bulletin 439. In 1970, the United States passed the Occupational Health and Safety Act (OSHA) which became effective in early 1971. That act covered all sorts of workplace activities including Tunnels and Shafts in 29 CFR 1926.800. In 1989, a revised and renamed 29 CFR 1926.800 was issued for Underground Construction. Some of the changes introduced in this rule were the outgrowth of improvements made in the California and Michigan codes after the 1971 accidents. These new regulations are the "Rules to Live By" for tunnel construction in the United States and are generally accepted as appropriate for tunnel construction throughout the world.

Jan 1, 1995

By Josh Struble, Fu Yuet, Jan Zywiel, Kevin King

This paper discusses the application of Integrated Inertial/GPS technology for position determination of earthmoving equipment in an open-pit mine. Different GPS augmentation methodologies are introduced and discussed. Principles for the operation of the Applanix POS MC (Position and Orientation System for Machine Control) are also presented, together with test results conducted at the Twin Creeks Newmont mine, using the POS MC and Caterpillar’s CAES (Computer Aided Earthmoving System).

Jan 1, 2005

By A. Bruynesteyn

Most ores and coals contain sulphide minerals such as pyrite, FeS2, the sulphur portion of which is a ready substrate for a variety of sulphur oxidizing bacteria. Although there are several bacteria capable of oxidizing sulphide minerals, the most often discussed culprit is Thiobacillus ferrooxidans.. Oxygen from the air slowly oxidizes pyrite into sulphuric acid, but T- ferrooxidans can increase this reaction rate several 100,000 times.

Jan 1, 1991

By K. L. Bickel

Catalyzed diesel particulate filters (CDPFs) are used for reducing diesel particulate matter (DPM) concentrations in underground mines. The U.S. Bureau of Mines is conducting research on how catalyzed diesel particulate filters perform. Two CDPFs, with two different catalysts, are used on vehicles in two mines. The CDPFs are periodically removed from service and evaluated in the laboratory to determine their DPM collection efficiency, regeneration temperature, and effects on gaseous hydrocarbon (HC) and carbon monoxide (CO) emissions. This report summarizes the results of the laboratory evaluation, and the mines' experience with the CDPFs. Both CDPFs have operated over 2,000 h. One was evaluated after 1,646 h; its collection efficiency at one operating condition was 87.3 pct. After 2,135 h of operation it was removed from service because it was damaged. The second CDPF continues to be used after 2,328 h of service. The laboratory evaluation indicated its collection efficiency decreased after 1,584 h of use and its regeneration temperature increased from 405' C to 420' C. The mines' experiences with the two CDPFs varied. While being used on mine vehicles, both CDPFs became plugged with DPM on a number of occasions because of insufficient regeneration. CDPFs are capable of lowering DPM concentrations in diesel exhaust. They can also lower emissions of CO and HC, depending on the type of catalyst used. In this study, the performance of the CDPFs changed with use. Recommendations are given in this report for proper use of CDPFs in mines.

Jan 1, 1994

By W. K. Collins, C. L. Dahlin, D. C. Dahlin, W. K. O’Connor, G. E. Rush

Direct mineral carbonation has been investigated as a process to convert gaseous CO2 into a geologically stable final form. The process utilizes a slurry of water, with bicarbonate and salt additions, mixed with a mineral reactant, such as olivine (Mg2SiO4) or serpentine [Mg3Si2O5(OH)4]. Carbon dioxide is dissolved into this slurry, resulting in dissolution of the mineral and precipitation of magnesium carbonate (MgCO3). Optimum results have been achieved using heat pretreated serpentine feed material and high partial pressure of CO2 (PCO2). Specific conditions include: 155°C; P002=185 atm; 15% solids. Under these conditions, 78% conversion of the silicate to the carbonate was achieved in 30 minutes. Process mineralogy has been utilized to investigate the appropriate feed characteristics, identify the process products, and interpret the mineral dissolution and carbonate precipitation reaction paths.

Jan 1, 2001