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Experimentally determined and theoretically explained phenomenon of zonal disintegration of rock around the development working brings about the radical changes in existing ideas about the mechanism of interaction rock massive with engineering constructions.The essence of the phenomenon consists in the fact, that forming of non-elastic deformations zone goes on by way of more intensive deformation and destruction of rock simultaneously in several zones, covering partially or fully output circuit and divided by zones of destructed rock. Under the influence of change of massive strained-deformational condition of depositional rock an accidental deviation of zones of supplementary expansion and compression of rock from the previous positions take place. One can observe multiplicational change of the outline, size and form of all disintegration zones in the time within the area of the working influence at massive. This phenomenon was named "fluctuation of zonal disintegration of sedimentary rock around development working".

Jan 1, 1991

By David E. Nicholas, Steven R. Dismuke, Paul F. Cicchini

The Buick mine, located 195 kilometers (120 miles) southwest of St. Louis in the Viburnum Trend, is owned and operated by Homestake Mining Company. The mine produces lead and zinc ore from a room and pillar mining method at a depth of approximately 335 m (1 100 ft). The Buick orebody typically averages 60 to 120 m (200 to 400 ft) in width with ore thicknesses ranging from 2.4 to 36.6 m (8 to 120 ft). The mine is divided in two; the halves are referred to as the North mine and South mine orebodies. The North mine orebody contains the higher grade ore; however, the developed reserves for the South mine orebody comprise about 60 percent of the total developed reserves for the Buick property. Existing pillars represent one-third of the total developed reserves.

Jan 1, 1986

The Mount Lyell Mining Field is Australia's chief productive source of copper. It is situated near Queenstown, on the western flanks of the West Coast Ranges, about 20 miles from the west coast of Tasmania (Fig. 1).The following observations on the mineral composition of the copper ores of the Mount Lyell Field are based on a...

Jan 1, 1939

By D. Yu. Paleev, O. Yu. Lukashov, A. Yu. Krainov, E. R. Shrager, I. M. Vasenin

The gas-dynamic method is presented of calculation of explosion-proof distances during an explosion of the methane-air mixture in mine working. On the basis of this method is modelled of shock waves interaction with explosion protective parachute partitions, obstructions and water barriers. Calculations have been carried out of attenuation factors of shock waves during their interaction with explosion protective structures, arranged near conjugation zones of mine workings. Possibilities have been analysed of suppression of intensity of shock waves and of propagation of shock waves control in mine working network of coal mines by installation of explosion protective structures.

Jan 1, 2003

By Kewal K. Kohli, Thomas Z. Jones

This paper presents a simplified computerized method for the prediction of maximum subsidence and the subsidence profile for the Appalachian Coal Basin using the Hyperbolic Function Profile Method. Several case histories are cited to demonstrate the appropriateness of the predictive method. In addition, sample runs and a detailed listing of the computer program is provided. Other popular subsidence prediction methods are discussed and compared with the Hyperbolic Function Profile Method.

Jan 1, 1986

Two structurally and mineralogically distinct sulphiderich veins cross-cutting the disseminated sulphides of the Nairne Pyrite Member appear to be products of local remobilization of sulphides under fracture-induced free energy gradients during regional metamorphism and tectonic deformation.The contrasting mineralogy of the two vein types may have arisen as a result of differences in the structural orientation of the veins and!or the relative ages of the veins.

Jan 1, 1969

By S. Peterson, E. C. Westman, P. L. Swanson

Coal bumps are brittle, violent failures associated with high stresses and competent host strata. To study bump mechanisms, conditions in the vicinity of a deep longwall mining face in bump-prone strata were monitored using three discrete systems. First, a microseismic monitoring network recorded mining-induced seismic events throughout the mine and surrounding strata. Second, pressure variations and distributions on the longwall shield legs across the face were recorded. Last, tomography surveys imaged seismic transmission properties ahead of the face. Results from the three systems were correlated in an effort to increase understanding of mining-induced stress redistribution and bump potential. An initial, one-week study showed that the correlation between averaged tomogram values and seismically active areas had a coefficient of correlation (R) of 0.89. Further results of these studies demonstrate that the tomography system is capable of imaging heavy shield-leg loading and bump-prone conditions prior to them disrupting the face operations.

By A Giblett, T J. Napier-Munn

This paper presents the results of a test program evaluating the impact of sample mass on the precision of Stage 1 gravity recoverable gold (GRG) test results. Four ore types ranging from low to high GRG contents were the focus of testing. A method to predict the influence of sample mass on the confidence limits of the Stage 1 GRG test result is demonstrated. The results suggest that although small samples tend to overestimate Stage 1 GRG in samples with low gravity gold values due to higher mass pull to concentrate, such samples can give acceptable estimates of the Stage 1 GRG content with focussed sample treatment protocols.CITATION:Giblett, A and Napier-Munn, T J, 2015. Measuring the influence of sample size on the precision and accuracy of gravity gold estimation, in Proceedings MetPlant 2015, pp 367–372 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By E. H. Myrhaug, K. Aasly, T. Malvik

Quartz is one of the main raw materials for the carbothermic production of ferrosilicon and silicon metal. The ideal process is written: SiO2 + 2C = Si + 2CO The real process is much more complicated, depending on the quality of the raw materials. Several research projects have been carried out on quartz for the (Fe)Si process during the last 50-60 years. One of the important properties that have been discussed in this review is the volume expansion that takes place between 850 °C to 1000 ºC and explosive disintegration for some quartz types. No final and definite conclusions have been made but several reasons have been mentioned: The influence of the phase transformation to tridymite, which takes place within the same temperature interval, has been discussed in several papers. Alkali impurities have been mentioned as a critical factor for this transformation to take place. Other researchers have mentioned mica impurities as a critical factor for the behavior of the quartz at these temperatures. Studies of fluid inclusions in quartz was reported in some papers focusing on the volume expansion of these during heating as a source of explosive disintegration, especially along planes of healed micro fractures that often contain vast numbers of such inclusions. Several methods for investigations of the important properties of quartz have been presented and these provide a good basis for the further research on quartz raw materials.

Jan 1, 2007

By R L. Brathwaite

The epithermal gold-silver deposits wall poster is one in a series of posters on different mineral deposit types being produced by GNS Science to raise awareness of the characteristics of New Zealand mineral deposits and their prospectivity. Epithermal deposits consist of quartz veins, quartz vein stockworks and hydrothermal breccias that are mainly hosted in subaerial andesitic or rhyolitic rocks of Tertiary age. The deposits were formed at depths of typically less than 1 km and at temperatures between 180¦ and 320¦C, although ore grade mineralisation was generally deposited at less than 270¦C.   In New Zealand, epithermal deposits occur in association with late Cenozoic volcanic rocks in the Northland, Coromandel and Taupo volcanic regions. All of the past and present gold production, estimated at greater than 380 t (along with 1300 t Ag) comes from the Miocene-Pliocene Coromandel Volcanic Zone, where about 50 epithermal gold-silver deposits occur over a 200 km long belt. In Northland, silver and mercury have been produced from hot spring type epithermal deposits, and several gold-silver prospects have been identified. Ore grade gold-silver mineralisation is currently being deposited in several active geothermal fields of the Taupo Volcanic Zone, and extinct geothermal systems occur on the western side of the zone. The active systems have provided natural laboratories to help understand the processes of epithermal mineralisation.

Jan 1, 2005

By U. Paschedag, H. Bussmann

"Bucyrus manufactures the most comprehensive product portfolio of mining equipment worldwide. Its mission is to have a positive, lasting effect on our world. Bucyrus makes sustainable development a fundamental way of doing business through economic, environmental and social initiatives that support, educate and benefit our employees, customers, shareholders and other stakeholders. Our participation in GRI (Global Reporting Initiative), a network-based organization that has pioneered the most popular sustainability reporting framework will be discussed as well as examples will be given on each major field of engagement. Two examples from surface machinery are most fuel efficient haul trucks as well as the Highwall mining system which allows access to coal reserves which are lost not making use of this kind of system. Two examples from underground machinery are Bucyrus’ automated plow systems for the mining of medium and thin coal seams with minimum rock and Bucyrus’ intelligent CST drive system for high-powered armored face conveyors (AFCs) for efficient use of energy."

Jan 1, 2011

By J. W. Butwell

Anaconda has been active In the Bingham mining district near Tooele, Utah since 1914 when the company acquired International Smelting & Refining Co. Over the years both custom ores and complex Pb-Zn-Cu ores from the district were milled and smelted at International. In 1948 Anaconda acquired the property that covers the present Carr Fork ore body. Since that time active exploration took place in the 50's followed by detailed geological evaluation in the 60's. Convinced that high grade Cu deposits would be found at depth, a deep drilling program commenced in the late 60?s, with intersection of the ore zone in 1969. Following extensive deep drilling in the early 70?s, a feasibility study was conducted in 73-74 with board approval given Sept. 6, 1974. The 9,000 t/d mine-mill complex was budgeted at $217 MM over a 5 year schedule with start-up in Sept., 1979. The following discussion includes the concentrator and surface facility portion of the budget or approximately $60 MM of the scope. Special emphasis will be made on equipment selection and layout.

Jan 1, 1980

By Philip C. Tully

[This bibliography contains 3,655 different citations to technical and scienfic literature on helium and alpha-particles, abstracted by 13 abstract service iblicatlons during 1964. Multiple subject classification increases the total number of entries to more than 5,800. Helium citations are listed by 22 major assifications, alpha-particles by 12]

Jan 1, 1970

By M. K. Larson, R. G. Wade

Researchers at the National Institute for Occupational Safety and Health (NIOSH) are studying the time-dependent response of rock stressed along weakness planes. The objective is to improve mine safety by reducing the number of roof falls that cause injuries and fatalities to miners. Researchers conducted direct-shear tests on mud-stoneovercored from a coal mine roof. Results showed frictional strength weakens with displacement along the shearing planes. Results of direct-shear creep tests also showed time-dependent deformation. Test measurements were compared to classical analytical models. Results suggest that risk of roof collapse may be decreased through layout and support design to reduce creep rates and thus slow progression toward failure.

Jan 1, 2000

By John E. Lens

Minutes after the Friday afternoon October 16, 2009 announcement that the 80 year old Lake Champlain Bridge was closed to traffic out of concern for public safety, emergency detour planning started at VTrans and NYSDoT. The closure severed a cross-lake link between Addison, VT and Crown Point, NY, which created a 76 mile detour and significant hardship for commuters, farmers working on both sides of Lake Champlain, and businesses relying on both traffic and employees commuting between Vermont and New York. Rehabilitating the bridge was determined to be economically and technically unfeasible and the design of a replacement bridge was accelerated for a spring 2010 construction start. In the meantime, a temporary ferry alternative was to be rushed into service beside the original bridge by February 2, 2010. This paper presents the case history of the fast-tracked ferry dock design and construction on the Vermont side. Twin 300-foot-long pile supported approach spans, a loading slip system and ice deflectors were designed, fabricated and constructed in 90 days in the fall/winter of 2009-2010. This chronicles the project from initial concepts through the extraordinary cooperation between state and federal agencies, and near round-the-clock winter construction on Lake Champlain. This project and its companion project on the New York shore succeeded by virtue of exceptional cooperation between seasoned regulatory, design, and construction participants and warrant this case-history presentation of the Vermont project to share within the industry as an example of overcoming extraordinary challenges.

Jan 1, 2011

By Frank Chase, M. Terry Hoch, George Karabin, Joseph C. Zelanko, Christopher Mark

Pillar recovery continues to be a significant ground control hazard. During the past decade, 10 miners were killed during pillar extraction operations in southern West Virginia. Studies conducted during the past decade have identified a number of “risk factors” that can be used to evaluate pillar extraction plans: •Cut sequence •Final stump •Timber or Mobile Roof Supports •Roof bolting •Intersection span •Depth of cover •Roof quality •Age of workings For each of these factors, rock mechanics science suggests which alternative would be expected to be more risky. For example, numerical models were used to evaluate different cut sequences, and indicated that less roof convergence occurred with the outside lift method than with the Christmas tree in the particular environment simulated. For many of the risk factors, accident statistics confirm the science. One finding was that currently almost 70% of the retreat coal in southern WV is being mined with MRS. In contrast, timber supports were used in 70% of the past decade’s pillaring fatalities. This paper discusses each of the risk factors in turn, presents the relevant accident statistics, and shows how the risk factors can be combined to estimate the overall hazard. It also addresses the use of pillar design to minimize the risk of global stability hazards including squeezes, massive collapses, and bumps.

By William I. Busenbark, Elmer C. Newman

At Bingham Canyon, the world's largest open-pit copper mine, annual grease consumption is in the neighborhood of 109 000 kg (240,000 lb), all of which was 544 (120-16) purchased, warehoused, and distributed in 54-kg (120-1b) and 180-kg (400-1b) drums. While perhaps a menial and mundane chore, grease distribution shows on the ledger as a significant expense item. To improve labor and cost performance, Kennecott maintenance engineers undertook a study to find the most direct method for moving multi purpose grease (MPG) from the refinery to the point of final consumption. What they found was a direct vendor system for hulk grease so simple and flexible that long-established drum distribution is being phased out in favor of the newer method throughout 75% of the operation.

Jan 9, 1977

By Allen L. Frank

The uranium mine environment is characterized by airborne radon-222 and its daughter products to which miners are exposed through breathing and by gamma and X rays from the uranium-235 and uranium 238 chains to which the miners are exposed externally. The nature of the radon-daughter concentrations and the methods used to define and measure the exposures are explained through an extensive review of the literature. An improved passive track-etch dosimeter for personal use is proposed which has a measurement range of about 30-400 WLH with a 95% confidence interval to ~25% for individual detector measurements in relatively stable mine air. Some measurements of these dosimeters adapted to environmental use are also presented. A program of development for enhancement of dosimeter sensitivity and greater accuracy of measurement is outlined. Extensive gamma-ray survey measurements were made in two Colorado and three New Mexico mines. Follow-up personal miner dosimetry with LiF TLDs was done at the mine with the highest exposure rates, The average miner exposure rate measured was 4.27 mR per day, or 9.3 of the maximum permissible level averaged over 13 weeks. Comparisons are made with previous mine surveys and their value in estimating miner exposure is discussed. Some depth-dose measurements made using Lucite as the absorber are evaluated.

Jan 1, 1978

By B. Hilscher, P. Nayak, N. Yoon

"The mining industry is currently facing challenges with declining feed grades and is struggling to find solutions to improve the project’s economic value. By means of pre-concentration, ore sorting aims to separate the barren material from the valuable ore to reduce energy consumption and tailings generation, while increasing the feed grade, concentrate grade, mill recovery, and revenue. In addition, ore sorting allows the modification of deposit geometallurgy in order to allow the creation of an optimal mill feed.This paper evaluates the applicability and challenges of ore sorting by utilizing the results from four different mines, and reviews them in detail. The mines include two underground and two open pit mines that are base metal and precioius metal operations. In order to understand the applicability of ore sorting in these operations, initial rock-by-rock test results and different types of assays (atomic adsorption [AA], inductively coupled plasma [ICP], and fire assay) are utilized. Using the assay results, the grade recovery curves for ore sorting are generated and they are further improved by using and developing an ore sorting algorithm, which is discussed in this paper. The application and evaluation of ore sorting in greenfield and brownfield properties will also be discussed.The state of the art ore sorting technologies for both rock-by-rock and bulk sorting are reviewed in this paper. The future technologies on the horizon, including different combinations of sensors, are explained. The sorting technologies include, X-ray transmission (XRT), X-ray fluorescence (XRF), colour, infrared, electromagnetic, and laser induced breakdown spectroscopy (LIBS).IntroductionOre sorting is a sensor-based sorting technique introduced between the excavation stage and processing stage, where the unwanted waste is diverted to the waste dump and only the ore is sent to the mill for further processing. As a result, the quality of the material entering the mill is improved and the dilution of the ore is reduced. In greenfield projects, sensor-based ore sorting provides an opportunity to reduce the capital cost of the project and increase the return on investment (ROI). With most operations currently facing the challenge of finding a high grade deposit, having a sorting unit provides several advantages while keeping the cost at minimum."

Jan 1, 2017

Magnetite cenospheres 40-270 I/m in diameter have been found during the combustion of pyrite concentrate.Micrographs of the surface and internal structures are presented together with comment on the mechanism of forrnation.The similarity to cenospheres found during the combustion of pulverized fuel was noted and speculation raised to their contribution to the dust and fume load in flash smelters.

Jan 1, 1980