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By W. K. Hitchcock

Hydrogen is regarded as being a high temperature indicator of spontaneous combustion. It is currently used in underground coal mines to detect advanced heating?s. Previous work has mostly consisted of small scale tests with high air flow to mass ratios. A large-scale test rig has been used to investigate the gas indicators of coal self-heating. In particular, the relationship of gas evolution, the location of its evolution and the temperature at which it is evolved has been examined. It has been found that there are two distinct zones of hydrogen production: one at the hot spot and the other in an oxygen deficient moist zone downstream from the hot spot which is at a relatively low temperature of approximately 100°C. This has implications for the interpretation of mine atmospheres.

Jan 1, 2009

By Lloyd Williams

1. The investigation shows that the Poplar Creek and Big Mary beds contain the largest known recoverable reserves of coal in Morgan County, Tenn. The Poplar Creek bed has been the most productive. 2. Known measured and indicated reserves of coal, based on a minimum bed thickness of 14 inches and on 1,800 short tons per acre-foot of coal in place, are estimated to be 96 million tons, as of January 1, 1954. Of this total, 59 million tons is in beds 28 inches and more thick. Areas in each bed were omitted from the estimate because available data relative to the bed characteristics were too meager to make an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to the total estimated reserves.

Jan 1, 1956

Jan 1, 1963

By M. ROWE, H. E. Gilliland, L. BARNES

The authors of this paper are to be commended for a clear exposition of a timely subject. However, some important conclusions, in addition to those presented in the paper, can be drawn from the results of their elaborate and rather complete numerical computations. First of all, the major part of the calculations presented in the paper are for semi-infinite slabs of oil shale (the authors designate this as Model I) and a question must be posed — Are these elaborate computations needed to arrive at realistic estimates of the shale oil displaced. Consider the model of Lauwerier* that corresponds to the authors Model I if thermal conduction parallel to the fracture be neglected. If one also neglects the finite (but relatively small) heat capacity of the material in the fracture, it is easily shown from Lauwerier's solution that the cumulative oil production would be:

Jan 1, 1969

By M. Javier

Mining, waste is growing problem both physical accumulation and increasing toxic uncertainties it presents in the long run. Its value ?zero? is strictly calculated by economy. This mining model begs the question: What is the value of waste & what does it represent to the mining industry? Waste is widely accepted as a ?by product? generated as a consequences of the mining process. The abundant waste accumulation affects society, as receptor, in many ways and the waste piles of materials has no use and no destiny. In reality, this waste is monument of imperfection of the extractive industries worldwide. Our planet is finite and has strict limitations, which mining has traditionally ignored. It is time to design a new system, in which clearly, waste design must be integrated in whole mining process; it has no room to postpone. This paper presents a concept in waste design by which toxic mining waste not only can be rendered inert but also act as nutrient to help balance the ecosystems. This concept calls for extractive industries to pursue EQUILIBRIUM with nature (Geomimic). Also, this concept offers countless gains and opportunities fro the industry and by converting liabilities into assets; mining engineers become the managers and stewards of nature. Also, waste design offers new solutions for proper and sustainable waste management of the mining industry.

Jan 1, 2011

By P. C. Thakur

In Part I of this paper, it was established that the width of longwall faces in highly gassy mines is primarily limited by the volume of air reaching the tail-end of the face. The ventilation air reaching the tail-end of the face should be not only enough to keep methane concentrations below the statutory limits (generally 1 percent) but also enough to prevent any gas layering. The air volume leaking from the longwall face into the gob should also be able to push the explosive methane-air mixture away from the gob area immediately behind the longwall face where active roof-fall is taking place (typically 30-45 m). The second group of variables that also controls the width of the longwall panel consists of (a) the rate of advance, (b) bleeder air quantities, (c) specific methane emissions for the gob area and, (d) efficiency and cost of gob gas capture. This paper will discuss the second group of variables and its impact on the optimum width of longwall faces in highly gassy coal mines.

Jan 1, 2009

By H. Mitri

A new monitoring device called SAFEBOLT (Stress And Force Evaluator in BOLTs) has been recently developed at McGill University. The device is essentially an alternative to the load cell, it permits the monitoring of bolt axial load in the field. The SAFEBOLT system consists of a portable readout unit, a connecting cable and the SAFEBOLT device, which is installed in the bolt head. The new device can be installed on any industry standard rockbolt or rebar. The device is completely encapsulated in the bolt head, which makes it resistant to corrosion, rugged, and free of any electric wires. Pilot tests at two underground Quebec mines were carried out and helped improve the initial design of the device head.

Jan 1, 2002

By E. J. Haug, K. L. Clifford, K. L. Purdy

St. Joe Minerals Corp.'s Southeast Missouri Mining and Milling Division produces lead, zinc and copper sulfide concentrates at three of its operations. The Viburnum and Fletcher mills have been described in previous papers. The new Bushy Creek mill, dedicated in May of 1973, is an updated version of the Fletcher mill incorporating 8.5 m3 (300 cu ft) lead and zinc

Jan 2, 1979

By Richard Gertsch, Jack Eloranta, Leslie Gertsch

An ongoing research program is characterizing the ore qualities that most affect mine and mill processing of iron. Current practice uses assays of magnetic iron and silica, but additional qualities are needed for advanced process control. If additional qualities can be measured from core, blastholes, or process samples, they can be modeled and controlled similarly. What qualities, other than assays, hinder or facilitate beneficiation at each processing step, and how can they be measured in the mine/mill ore stream? This paper describes preliminary determinations of the effects of ore chemistry, hardness, blasthole drill performance, fragmentation control, and grindability on mill performance.

Jan 1, 2005

Kinetics of Reclamation of E-Waste by a Bioleaching Route

Sep 13, 2010

By D. A. Cormode

"INTRODUCTIONPine Point Mines, operated by Cominco Ltd., is located approximately 55 miles east of Hay River, N.W.T. by the southern shore of Great Slave Lake.The milling operation commenced in the fall of 1965 at a design capacity of 5,000 tpd. An addition which came on stream late in 1968 raised the nominal capacity to 8,000 tpd. Currently the milling rate is 11,000 tpd.The lead and zinc sulphides occur in dolomite host rock. Typical feed grades at present are 2% lead, 5.5% zinc and 5 % iron. When dolomite is present even in relatively minor amounts in the zinc concentrate, it presents serious treatment problems and causes inefficient operation of electrolytic zinc refineries.By 1972, it had become apparent that magnesium rejection in the form of dolomite was deteriorating because of increased plant throughput of less amenable ore. This paper will briefly outline the Pine Point zinc flotation circuit and will discuss the two phase program for reducing the magnesium level in the zinc concentrate. The program included changes and alterations to the flotation circuit and the construction of an acid leaching plant."

Jan 1, 1977

I am wearing two hats today. When the invitations went out to participate in this forum, two were received in the head office of the Department of Lands and Survey - one addressed to the Director-General of Lands and one to the Chairman of the National Parks Authority. It seemed logical that as the department is responsible to the Government for the administration of the National Parks Act 1952, we should respond by providing one speaker to cover both the department's interests and those of the National Parks Authority. I hope, however, that this will not blur the clear distinction which exists in the context of the mineral industry between Crown land on the one hand administered by the department for the statutory Land Settlement Board and national parks and allied reserves on the other hand which are the responsibility of the National Parks Authority.

Jan 1, 1976

By Christopher J. Bise

Volume II of this collection of research reports, entitled "Model Training Program," provides the framework and details for developing a tailored training program for a specific mine based upon documented human-performance deficiencies. To do this, several steps must be followed prior to program implementation: 1) background information must be gathered (database analysis), 2) direct observation of indicated problem areas should be conducted (safety sampling), and 3) separation of those deficiencies to be addressed through training from those which would be better addressed by workplace or equipment redesign (trainability assessment). Once training is determined to be the appropriate strategy for addressing the noted deficiencies, several approaches can be taken, depending upon whether the problem is related to repetitive work procedures in a predictable, a variable, or a dynamic workplace with a substantial amount of interaction between workers, equipment, and the environment. Although this volume and the subsequent seven volumes provide examples of how the training information was field tested using various strategies (for example, loss control, task training, etc.) and techniques (for example, microcomputer-based exercises, lectures, etc.), the ultimate selection of the delivery method is based on cost/benefit analysis. Therefore, the Model Training Program has incorporated a Training Cost Model as a desirable component.

Jan 1, 1993

By A. F. Deng

A general description of the project, mainly the pier foundation design of the ZHU JIANG FANYING is presented in the paper. The major contents include the foundation scheme, the evaluation of bed-rock characteristics, the allowable bearing pressure, the design and construction of pier foundation.

Jan 1, 2010

By Justin Srednicki, Chenming Zhou

Ambient electromagnetic (EM) noise (natural or manmade) is a major limiting factor for the design and operation of many electronic devices, including through-the-earth (TTE) communications and tracking systems. Extensive studies on EM noise were conducted by the US Bureau of Mines in the 1970s and 1980s. Changes in the design and operation of electrical equipment since then, however, have resulted in changes in the EM noise environment. This paper reviews past research on surveying EM noise in the extremely low-frequency (ELF) and very-low-frequency (VLF) bands, which are the operating bands for TTE systems, and introduces a new battery-powered, rugged, portable measurement system for surveying EM noise in mining environments. Examples of surveyed EM noise measurement results in and above an active underground coal mine, using the new system, are presented in terms of absolute magnetic field strength levels. A new metric, average noise level (ANL), is introduced to characterize the noise level relative to a particular frequency band for a specific location. It is found that EM noise in mining environments varies significantly with time and location. EM noise levels at frequencies of 30 Hz that shifted from power harmonics (e.g., 90, 150, 210, 270 Hz) are relatively low and their variation with time can be statistically modeled by a Gaussian distribution. The conclusions and findings presented in this paper can help better design and operate TTE communications and tracking systems in underground mines.

Oct 14, 2022

One of the most significant problems experienced in land reclamation work has been the tendency of earthmovers to over-compact the subsoils and topsoils. The need for extensive subsoil drainage, because of over-compaction, becomes a very expensive exercise and can be attributed to poor planning. The problem has been addressed both at the Waihi and Huntly open-cast mines through the use of low ground pressure machines in the placement of subsoils and contouring. The use of subsoilers working to contour to aerate the soils is essential to integrate both the sub and topsoils so that significant root growth and drainage is established. Waihi's rainfall (approximately 200 mm annually) and light soils create difficulties in preparing for the final seed bed. A noticeable factor in preparation of the growing medium was the reaction of the lime particularly in the subsoils (damp), from a lumpy, quite heavy texture to almost a seed-bed texture within a period of approximately 72 hours. Also the high incidence of stone and debris which was not apparent in the placement of subsoils meant the job became very labour intensive. This will be overcome with the importation of a machine from the USA. All of the rubber tyred tractors used on these projects are four wheel drive in the 6S-aOhp range which for weight distribution and the safety factors allows for good landscaping techniques. Good engineering practices should ensure that slopes of no more than 3:1 be designed, keeping in mind that the long term planning must allow for maintenance and stock management of restored land.  In the preparation of the final growing medium the equipment used included: Caterpillar 05 LPG and blade; three-four wheel drive rubber tyre tractors; Super flow subsoiler; hydraulic twin spinner manure spreader; discs û two types; harrows; MF Seeder; Cambridge Roller and Duncan Rotatiller.

Jan 1, 1991

By M Olsen, L van den Berg

Bowen Basin coalmines suffer from hot and humid ambient conditions during the summer period. The ambient conditions combined with high VRTs, increasing depth of working and significant equipment heat loads results in heat issues underground. Coalmines operate under heat stress management plans as required by legislation with associated trigger action response plans (TARPs). Some mines also employ refrigeration as part of their heat management strategy.A recent case study was conducted on a mine producing about 4.5 Mt/a from their longwall and experiences summer surface ambient temperatures of about 23.5ºCwb. The expected virgin rock temperature is 46ºC at 300 m depth. The mine currently introduces a modest amount of surface cooling at the portal using ‘off-the-shelf’ air conditioning units. This system does not effectively manage face temperature primarily due to positional inefficiency.Underground conditions remain hot in summer and work is typically undertaken in accordance with the Heat TARP. This has a direct impact on the productivity of crews, worker comfort and also negatively impacts the workforce morale. The mine commissioned a study to determine a refrigeration strategy aimed at maintaining underground conditions below TARP levels 90 per cent of the time.The ventilation network model was calibrated against actual temperature data to simulate the heat loads including longwall, conveyor system, strata and auxiliary diesel fleet. This model was then used to determine the cooling requirements for bulk surface cooling, bulk underground cooling, surface district cooling and underground district cooling strategies.These estimates were used to undertake a total owning cost trade-off for the different strategies. The study concluded that a chilled air shaft has the lowest technical risk but the highest total owning cost due to shaft development needs. Introducing chilled water to an underground cooler via boreholes offered the lowest total owning cost and was therefore recommended.CITATION:van den Berg, L and Olsen, M, 2017. Heat load assessment and mine cooling strategies for a longwall coalmine, in Proceedings Australian Mine Vent Conference 2017, pp 231–236 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By R. Gensemer

A number of state and federal agencies are calling for development of aquatic life criteria for conductivity. These aquatic life criteria or ?benchmarks? are based on observed correlations between conductivity and benthic macroinvertebrate community composition, generally measured by composite metrics or indices. However, development of an aquatic life criterion for a composite variable like conductivity is made difficult by a number of factors. Based on a database from West Virginia, observed patterns of invertebrate community composition versus conductivity may instead be related to a combination of abiotic (e.g., ionic composition, habitat) and biotic (e.g., life history, colonization potential) factors. Many benthic invertebrate taxa also do not respond to increasing conductivity in a consistent relationship. Many states have determined that a composite variable, like conductivity or TDS, is not appropriate for criteria development, as many studies have shown that toxicity varies as a function of ion composition and can be mitigated by elevated hardness. We conclude that the relationships between conductivity and changes in benthic macroinvertebrate community composition are neither strong nor reliable enough to warrant derivation of a criterion based solely on conductivity.

Jan 1, 2011

By T. F. Mitchell, B. K. Shibler, J. V. Batty, W. G. Sandell, G. M. Potter

"INTRODUCTION The Park City district, situated 30 miles east of Salt Lake City, Utah, in the Wasatch Mountains, Is a well-known producer of lead, zinc, and precious metals. Nearly continuous production has been maintained from the dis¬trict since its early discovery about 1870. For approximately 50 years, gravity milling methods were employed to beneficiate Park City ore, and during that time tailings from the mills were sluiced down Silver Creek and deposited on lands below the camp for 7 miles.Owing to the large tonnage of tailings deposited along Silver Creek, considerable work was done in the past in the attempt to develop a low-cost concentration method for re-treating this material, but no-method was found that was economically feasible. The Bureau of Mines was asked to conduct beneficiation tests on Park City tailings in November 1944, and metallurgical studies were initiated at that time. This report summarizes the results of laboratory ore-dressing studies made on samples from the Grasselli deposit."

Dec 1, 1947

By M. M. Rajkovich

Just prior to the close of the century, the Federal Mine Safety and Health Review Commission issued its long-awaited decision in Berwind Natural Resources, et al v. Secretary of Labor, to usher in the new millennium. The case arose as a result of a mine explosion in Eastern Kentucky resulting in MSHA’s issuance of 225 citations, not only to the contractor, but to four affiliated entities of Berwind Corporation. While an Administrative Law Judge dismissed those citations as to three of the Berwind entities, both MSHA and the remaining Berwind entity appealed the case to the Commission. Although the Commission effectively left intact the Administrative Law Judge’s decision, it announced a new theory of liability that would apparently be applied in the future, namely the Unitary Operator Theory. This presentation will provide an in-depth look into the Berwind decision and explore the means under which MSHA might impose liability for contractor violations upon other entities in the future.

Jan 1, 2001