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By Michael S. Roscoe

In order to more accurately predict longwall surface subsidence over the Pittsburgh No. 8 Coal in Eastern Ohio, North American Coal Corporation's Quarto Mining Company undertook or participated in several subsidence studies. Due to the changing roof geology and rapid variations in the amount of cover two separate areas were investigated at two different mines to determine the subsidence response if any to these changes. Data generated from these studies were compared with NCB derived,data for accuracy and then used to predict subsidence under houses, gas lines and other critical man made structures. The following report summarizes the results of these studies as well as the subsidence case histories of gas lines, transmission towers, houses and water wells. Problems that were encountered during both phases of this process (investigation and subsequent application) are also included.

By W. R. K. Wu

Results of linear correlations of two to four variables by the least-squares method are presented. The variables include 63 parameters representing coal composition, coal plasticity, and coke strength. The composition parameters are on chemical analyses; the plasticity parameters, on three plastometer and dilatometer tests and four miscellaneous tests; and the coke-strength parameters, on three ASTM indices. Seventy-two to eighty-four plastic coals were used in the plasticity and carbonization tests, which together form the basis of this report; 43 nonplastic or weakly plastic coals were used in the coal-band studies. Plots of relations between volatile matter, carbon, and oxygen contents of 1,860 U.S. coals and the 84 coals used are shown. Similar plots between volatile matter and hydrogen or atomic H/C of the 84 coals are also included. Significances of regression coefficient signs for coal composition parameters in the significant correlations found are discussed. Based on these significances, the following relations are shown: (a) coke strength versus average aromaticity, or mineral matter content, of the parent coal; (b) characteristic temperatures of the plastometer and dilatometers, the free-swelling index, or the Gray-King type versus average hydroaromaticity of the coal; and (c) nontemperature parameters of the plastometer and dilatometers versus the physical properties of a certain group of compounds from thermal decomposition of coal. Similarly, significances between the positions of coals in the coal band and the aforementioned relations are also discussed. A structural theory of coal plasticity is proposed. Applications of the correlation results are discussed. Composition parameters, such as carbon, atomic H/C, and calorific value may be used as a basis for selecting coking coals for stronger coke. Plasticity parameters, such as the end temperatures of the plastometer and dilatometers and the free-swelling index, may be used for the same purpose. Based on the best correlations found, coke-strength indices may be estimated to within 4 to 8 units of the observed values; the end temperatures of the plastometer and dilatometer tests, 5° to 10° C.; and the free-swelling index, within 1 unit. Accuracies of all these estimated values are examined, based on the experimental errors of the data involved. Finally, estimations of plasticity parameters from one test with those from others are shown.

Jan 1, 1971

The history of the discovery and development of the Kambalda nickel orebody. is reviewed and the decision to process the Kambalda concentrates by the Sherritt-Gordon process at Kwinana is discussed. The Kwinana Nickel Refinery is described and the problems encountered in the first year of operation are Outlined.

Jan 1, 1971

By P. R. Smith, R. A. Walters

Borates have been mined in the desert areas of California and Nevada for more than 100 years. To about 1890, playa surface mining provided the chief sources of boron minerals. Underground mining of colemanite and later of borax and kernite was predominate until about twenty years ago. Open pit mining of the large deposits of borax and kernite near Boron, California has been most significant for the past twenty years. Mining of colemanite in the Ryan, California area, near Death Valley, began in 1907. Following the discovery of the large deposits in the Boron area (about 1957), mining in the Death Valley area became nearly nonexistent. Only small tonnages were mined for special uses. Little mining was done in the Boraxo area near Ryan. The first claim was made in about 1915. In 1960 the area became the property of the Kern County Land Company, which was acquired by Tenneco Oil Company in 1967. In 1976 the various boiate properties and claims in this region were acquired by American Borate Corporation. The open pit mine is now approximately 122 m (400 ft) deep, 910 m (3000 ft) long and 305 m (1000 ft wide). The borates in the Boraxo pit consist primarily of three minerals. These are about 50% colemanite (CB6011 5H20), about 40% probertite (NaCaB50g 5H20), and 10% ulexite (NaCaBgOg 5H20). The colemanite, along with boric acid and high-grade colemanite ore from Turkey provide the only sodium-free borates for production of textile grade fiberglas. When heated to its decomposition temperature, colemanite decrepitates to a fine powder, which is the basis for the concentration process. The gangue minerals in this deposit are primarily calcite and clays, including bentonite. The ore body has a very low arsenic content, which is a desirable feature. Test work had been done with samples prior to the results discussed herein. This paper will discuss results of test work which were the basis for erection of a plant, and the subsequent plant operations. Laboratory Calcination and Air Tabling Tests Laboratory calcination tests showed that substantial upgrading of the borate could be accomplished by calcining followed by screening of the calcined material. Removal of the + 28 mesh calcine resulted in borate losses of less than 10% with a rejection of 40 weight % or more of the calcine. The minus 65 mesh calcine generally met the requirement of containing 48%, or more, B203. The minus 28 plus 65 mesh material contained an intermediate quantity of borate and would require additional treatment. Testing demonstrated that ore would not have to be reduced to a size finer than 19 mm (3/4 in.) prior to calcination. A temperature range from 400 to 455OC (750 to 850°F) was apparently satisfactory. Calcination at a temperature of 48Z°C (900°F), or higher, was unsatisfactory due to fusion. All laboratory calcination tests were static tests conducted by placing small covered charges in a laboratory furnace for 40 min. In all tests vapor issues from the furnace for 5 to 7 min. Following this period the ore could be heard "popping," due to decrepitation of the colemanite. The reaction generally continued for approximately one-half hour. Various size fractions of the calcination products from laboratory tests were subjected to laboratory air tabling tests, usually after removing the plus 28 mesh material. Laboratory air tabling tests were conducted employing a Whippet V-80 model air table manufactured by Sutton, Steele and Steele Co. now known as Tripple S Dynamics. Variables include both end and side-tilt, speed of vibration, and quantity of air rising through the deck. In addition to the variables in the machine itself, the feed rate is also a rather critical variable. Testing demonstrated that all - 28 mesh size fractions of the calcine could be successfully concentrated to 48% F2O3 or greater. For the finer material recoveries into the concentrate were between 85 and 90% of the borate. With the coarser material a substantial amount of middling was produced which required cleaner tabling. Laboratory calcination and air tabling tests indicated a process whereby the borate could be concentrated to about 50% B203 with borate recoveries approaching 90%. Moreover, the iron content of the concentrate was well below the required specification of 0.3% Fe2O3. Pilot Plant Calcination Following the laboratory test work described above, pilot plant testing was conducted to prove the process, provide data for engineering studies, and provide product for a prospective purchaser. The kiln used was 0.9 m-diam (3 ft) by 9.0 m (30 ft) long and had a belly section 1.2 m-diam (4 ft) by 2.74 m (9 ft) long near the discharge end. The kiln was operated at a speed of 0.7 rpm. Gas was fired into the kiln at an average rate of 27.1 m3/hr (958.4 cu ft per hr). The air to gas ratio used was 10:1. The ore was fed to the kiln countercurrent to the flame and discharged through a hopper into a screw conveyor which discharged to a 1.2 m (48 in.) Sweco separator. The separator had 28, 65, and 150 mesh screen cloths, with the plus 28 mesh fraction being discarded. The minus 28 mesh fractions were later subjected to air tabling. The exit gases, containing some calcine dust, were swept through two cyclones to recover the dust. The gases then were scrubbed in a Ducon scrubber; very little dust reported past the first cyclone. The dust from the first cyclone was also saved in drums. In addition to the gas rate, the flue gas velocity, after

Jan 1, 1981

By W. L. Honnold

Owing to a unique labor situation and other unusual circumstances, the mining methods of the Rand are hardly comparable with practice elsewhere. They are of considerable interest, however, and their importance is increased by the magnitude of the' industry with which they are identified, gold of $166,186,000 value, say 40 per cent. of the world's production, having been recovered from 25,701,954 tons of ore milled in 1914. In the sketchy remarks to follow, attention will first be drawn to some influential factors of general bearing, after which certain features at two mines of the writer's group will be referred to. It is hoped that engineers associated with similar or different conditions and practice will contribute to broaden the discussion. Before proceeding, recognition is due the generous assistance of C. E. Knecht and F. A. Unger. General Observations The principal mines are situated along the northern limit of an irregularly shaped geological basin, and extend in almost unbroken continuity over a distance of about 60 miles. As the boundaries are defined by vertical planes there are both "outcrop" and "deep-level" properties, all differing in size and in technical features. So much has been written in regard to the geology of the Rand that only a few pertinent features need here be recalled. Briefly, the ore deposits are profitably enriched portions of certain conglomerate beds or "reefs," rarely more than three, which are interposed between quartzite, or quartzite and slate, and lie so closely together that where more than one are mined they are dealt with as a working unit, although they may be stoped separately. Their collective extension is locally referred to as " the Reef." Along the outcrop the series dips more or less steeply, and in depth it flattehs, the latter tendency being most marked in the Far East Rand, where the bottom of the basin is nowhere so deep as to be inaccessible. Dikes and faults are a common feature throughout. They are,

Jan 1, 1916

By Martin H. Stanczyk

The Organic Act of 1910 established the Bureau of Mines and gave it authority and responsibility for conducting research on separation, recovery, and recycling of waste products and scrap generated by the mineral and metals industries and the consuming public.(1)1 It was apparent to our Nation's leaders even then that mineral resources, once mined, are irreplaceable and that the development of methods for recycling the values contained in wastes would be required to solve the problem of even¬tual scarcity, Estimates of the increase in per capita consumption of mineral resources in this country indicate that the consumption of metals, minerals, and fossil fuels by 1980 will be double that consumed in 1970 (2). The United States can expect to meet its future mineral needs in three basic ways: the first is through increased production of primary raw minerals; second by increasing imports from foreign sources; and third by recycling secondary materials and metals that were formerly discarded as waste. Rather than consider these

Jan 1, 1972

By Thomas S. Lovering

Hot springs, geysers, steam-emanating fumaroles- these creatures of nature were until recently little more than geological curiosities, but today they are exciting the interest of engineers around the world for it has been shown that such hyperthermal areas can be profitably harnessed by man to provide heat and power for his communities. Although water from hot springs was used centuries ago to heat some Korean dwellings, is being used today by one-third of Iceland's population for similar purposes, and is finding industrial applications in New Zealand and elsewhere, the most dramatic use of geothermal energy has been its conversion into electricity. The largest installation at the present time is that at Larderello, Italy, where the Count of Larderello began to experiment in the production of electricity from geothermal steam in 1904. Eight years later after a quarrel with the local power company, the Count installed his first steam turbine, a unit of 250 kw capacity.

Jan 9, 1965

By G. J. Knighton

Introduction The Sullivan concentrator treats the complex lead-zinc-iron ore from the Sullivan mine of the Consolidated Mining and Smelting Company of Canada, Limited, to make a lead and a zinc concentrate for its metallurgical plants at Trail. Three miles separate the mine and mill, which are situated near the town of Kimberley, in the East Kootenay district of British Columbia. The orebody consists typically of banded sulphides, mainly galena, sphalerite, pyrrhotite, and pyrite. Important factors in the concentration of the ore are its exceedingly complex and its high specific gravity. It should be remembered throughout the paper that results and figures are based on Consolidated's experience with the Sullivan ore. The present mill feed rate is 8,500 dry tons of ore per 24 hours, for an operating week of five and a half days. Grinding and classification of the ore are carried out in three stages and, in addition, there is a re-grind section which re-treats the zinc middling. It is the purpose of this paper to discuss the classification in the various stages and to give the results o comparative tests which have been carried out for the purpose of improving operations in the mill. The Primary stage consists of six units, each made up of a ball-mill and classifier (see accompanying flow-sheet). Four units operate in open circuit and two in closed circuit. The secondary stage consists of eight ball-mills operating in closed circuit with twenty-one classifiers. In the Tertiary stage are two ball-mills in closed circuit with eight classifiers. The re-treatment section for re-grinding the zinc middling comprises one ball-mill in closed circuit with two classifiers.

Jan 1, 1947

By G. F. Loughlin

Nearly 55 years have elapsed since the U. S. Geological Survey was organized. During this period the mineral industries have grown from infancy or early childhood to well developed maturity, and some mining industries appear to be declining. Decline in mining is even more conspicuous in certain districts, or even states, than in any mining industry as a whole, and discoveries or developments of important new districts have been very few in recent years. Our reserves of most metals and nonmetals are adequate for many years of normal production, subject to changes in rate of exploitation that may be caused by foreign competition and by changes in technology and market conditions; but the declining production of many districts and the scarcity of important new discoveries to compensate for them is cause for some apprehension. It is likely that future production will depend to a considerable extent on deep exploration and on the thorough examination of places in and adjoining existing districts where significant outcrops are lacking and only apparently insignificant geologic features offer encouraging clues—more so than on the discovery of entirely new districts. Even the possible discovery of new districts, which have escaped the intensive search by the nontechnical prospector, must be dependent on geologic information. There is therefore no need for argument as to the value of geology to the mining industry; and the need of continuing to advance the science. The U. S. Geological Survey's past contributions to mining geology, as expressed in its official reports and other publications, are recognized by Ransome in his historical review of mining geology in the Lindgren volume.' These contributions have helped to form the basis of modern mining geology, which has grown rapidly in the last 25 years. This growth has witnessed the organization and maintenance of geologic staffs by mining companies in several districts, and their detailed work, together with the fact that nearly all of the larger mining districts have

Jan 1, 1935

By S. G. Sawyer

The Pittsburgh Safety and Health Technology Center (PSHTC) of the Mine Safety and Health Administration (MSHA) provides engineering and scientific support to the inspectorate personnel of MSHA. One of the Center's myriad roles is to assist in the investigation of mining accidents, especially those involving fatalities. Center personnel utilize forensics to help uncover the causes of accidents and to make technical recommendations on the prevention of future similar mishaps. To exemplify a typical forensic investigation, this paper documents the methodology used in determining the reasons for a boat sinking, which resulted in a double fatality on a mine company pond.

Jan 1, 1997

By R. E. Gertsch

Mechanical mining holds great promise for the mining industry. Realizing this promise depends on giving mine operators the capability to evaluate the higher production, the lower costs, and safety enhancement that comes with mechanical mining. The opportunities for low cost and high production must outset the high capital costs associated with mechanical excavation. Giving the mining industry the tools to effectively evaluate and successfully implement mechanical methods defines the challenges and directions of the mechanical mining industry.

Jan 1, 1994

By Max Friedemann, Alexandros Bousdekis, Anna Gustafson, Helmut Mischo, Håkan Schunnesson

Many devices used in mining are not monitored by sensors or do not have their own intelligence. By retrofitting sensors and real-time data processing, machines can be integrated into an existing digital infrastructure. Within the project Mine.io funded by the European Union a Sandvik DE110 exploration drill rig is being digitized using various AI algorithms at research and education Mine “Forschungs- und Lehrbergwerk Reiche Zeche (FLB)” of TU Freiberg. The aim is to increase the productivity of drilling with real-time evaluation of the current rock to be drilled and the current maintenance status of the drill rig. The drill rig is equipped with a speed sensor, pressure sensors in the hydraulics, 3-axis vibration sensor, borehole length measurement and temperature sensor. The sensors are additionally attached to the drilling rig and no structural changes on the drill rig are necessary. All data are processed real-time at a server structure outside of the mine using AI algorithms to analyze which rock (ore or host rock) is being drilled and to perform predictive maintenance. Processed Data are visualized for the operator to optimize the workflow and the productivity.

Feb 1, 2025

By C. A. Jeffrey, K. Pearson

The Croft diorite in central England belongs to a suite of Caledonian igneous rocks collectively known as the South Leicestershire diorite complex. Although the intrusions occupy separate outcrops, they are linked at depth to form a single pluton, buried beneath a cover of Triassic sediments (Le Bas, 1972; 1982, Allsop and Arthur, 1983). Both the Caledonian diorites and the over-lying sub-Triassic unconformity have been affected by a complex history of alteration and mineralization which can be subdivided into four stages: (1) deuteric effects, caused by the release ofvolatiles during magmatic cooling; (2) albitization through sodic enrichment; (3) formation of low-temperature laumontite, analcime and calcite veins with associated wall-rock alteration to prehniteand pumpellyite; and (4) sub-Triassic unconformity-hosted base metal, manganese and palygorskite mineralization. Zeolite mineralization occured some 200 Ma later than the intrusion itself, duringpost-Triassic times, as indicated by the presence of a single vein of laumontite and microcrystallinecalcite which cross-cuts the sub-Triassic unconformity surface and enters the overlying Triassic sediments. Evidence from ?uid inclusion work indicates that two ?uids were involved in the deposition of the zeolite veins. One ?uid was initially of relatively high temperature (~100°C to 320°C) and lowsalinity (~0.2 to 5.9 wt% NaCl equiv.), and was probably meteoric in origin, whereas the other wasof relatively low temperature (~41°C to 165°C) and high salinity (~0.4 to 16.72 wt% NaCl equiv.),and is interpreted to represent a basinal brine. During Triassic rifting, thinning and fracturing of the crust, with the possible rise of associated magmas (Halliday and Mitchell, 1984), could have increased permeability and heat ?ow, initiating the circulation of hydrothermal ?uids. Triassic unconformity-hosted base-metal mineralization in Central England is similar to other Triassic-Juras-sic mineralization in Europe (Mitchell and Halliday, 1976).

Jan 1, 1997

By Sunil Katharia

In February 2016, the upgraded Blast Furnace 1 of JSW Steel Limited (JSW) at its Vijayanagar Steel Plant was blown in after a 6 months shutdown in which the whole furnace was rebuilt on the existing foundation and within the existing tower structure. Despite several plant constraints it was possible to increase the furnace inner volume by 85% - reaching 2307 m3 from existing 1250m3. The upgradation project covered the stockhouse and its dedusting system, top charging system, furnace profile, furnace cooling system, casthouse and its dedusting system, slag granulation plant, pulverized coal injection plant, hot blast system and gas cleaning plant – with major interventions in order to cope up with the changed operating conditions. The total scope of the project was split by JSW into several packages, all based on design data provided by Paul Wurth. JSW was responsible for coordinating the local subcontractors along with Paul Wurth which has been appointed as main technology supplier in charge of complete basic and selected detail engineering in the key areas and of the supply of core equipment such as the Bell-less Top®, copper staves, GCP key items and TMT casthouse machines. The main design concept and the key points of the project such as optimization of project ROI, advanced erection concepts as well as a summary of the operating results are presented confirming JSW “BF1” upgradation as one latest examples of the current state of the art in the revamping projects.

Aug 17, 2017

By R. M. Porter

PILLAR extraction at the Sullivan Mine bas been in progress for over twenty-five years and bas .involved progressively larger pillars. The largest pillar blasted to date exceeds one million tons and is described in this paper. This blast is believed to be one of the largest to take place entirely under-ground. The Sullivan Mine, owned by The Consolidated Mining and Smelting Company of Canada Limited, is located in the southeastern corner of British Columbia on the east flank of the Purcell range overlooking the twenty-mile wide Rocky Mountain Trench (Figure 1). The orebody is a bedded replacement deposit in argillites, varying in thickness up to 300 feet, but averaging about 80 feet. Above the 3900 Level, the dip varies from nearly horizontal to 40 degrees; be-low the 3900 Level it varies from 45 to 20 degrees (Figure 2). Pillar extraction follows a plan of retreating outward from caved areas. The size of each blast is determined by the effect which the removal of support

Jan 1, 1961

Continuous, steady-state laboratory flotation tests showed that the recovery of cha1copyrite from a naturally occurring ore, under conditions closely resembling those of plant practice, could be expressed in terms of a first order rate equation.Tests on full-scale plant flotation cells, using impulse tracers, indicated ideal mixing of the pulp in the cells.It was demonstrated that values of first order flotation rate constants can onlv be obtained from conventional methods of analysis in special cases.Analysis of a plant sampling campaign by the author supported a first order kinetic equation for two mineral species, and for the individual size fractions of one of these.The effect of stage-addition of reagents is interpreted in kinetic terms.

Jan 1, 1966

By E. Ashworth

A thermistor probe has been developed to measure in situ temperature profiles underground. A full description of the probe is given. Data collected from the probe has been used to compare the actual profiles with those predicted from a finite element analysis using laboratory measured thermal properties of the different rock types. This comparison indicates the applicability of laboratory measured parameters in modeling the real conditions. Factors such as applied pressure, moisture content and anisotropy on laboratory measurements is discussed.

Jan 1, 1983

By J. E. Chilton

The Bureau of Mines has developed a portable flammable gas detecting system for estimating the flammable gas concentrations in a mine containing one or more combustible gases at concentrations up to 100 vol pct. With this portable detecting system, mine rescue or recovery personnel can quickly determine if they are working in a potentially explosive gas atmosphere and either leave the area or make appropriate changes in the fresh air ventilation of the mine to render the area safe. The detecting system uses a commercial, intrinsically safe, flammable gas detector with a range from 0 to 5 vol pct methane (CH4). The flammable gas detector has a catalytic heat-of-combustion sensor that can detect all flammable gases that would be encountered in a mine including methane (CH4), ethane (C2H6), carbon monoxide (CO), and hydrogen (H2). To determine the mine gas concentration, the rescue worker dilutes a sample with fresh air carried within the detecting system. The concentration of the diluted sample is then measured with the permissable flammable gas detector. The actual mine gas concentration is calculated from the product of the indicated diluted gas concentration and the system dilution ratio using a pocket calculator or the nomograph on the side of the unit.

Jan 1, 1987

By Robert L. Zerga

Mining equipment and systems have been incorporated into the San Manuel mine to meet the requirements of ore development and extraction. A general discussion of the existing equipment as it relates to the specific methods is presented. A comparison is made between original and present equipment, and future equipment needs. The problems, successes and failures of mining equipment adaptation for the San Manuel mining system are highlighted.

Jan 1, 1981

By F. R. Nogas

"Because of the elements of uncertainty and instabilitp associated with single-enterprise communities, there is increasing interest in the alternatives to developing additional new communities of this nature. Gulf Minerals Canada Limited has chosen a unique alternative means to accommodate employees at a new uranium mine/mill complex at Rabbit Lake in Northern Saskatchewan. Gulf has adopted a fly-in program which moves their staff from a 450-mile radius, in and out of the on-site facilities, on a 7-day rotation."

Jan 1, 1976