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By L. D. Tracy

Many bituminous coal-mining companies have inaugurated extensive safety programs, but the failure to have approved or permissible equipment or safe practice in only one part of a mine has resulted in disaster. The necessity of using only equipment bearing the U. S. Bureau of Mines approval plate is emphasized by the fact that many accidents are the direct result of carelessness on the part of trusted employees using non-permissible equipment. A concrete example is found in the case of an explosion on October 26, 1926, in a mine in the Pittsburgh district, Pennsylvania. Story of the Explosion At about 10 o'clock on the night of the explosion an examination was made in No. 2 butt left and parallel off No. 14 north, and was found to be clear of dangerous accumulations of gas. (See figure). Several hours later a crew of two men brought a self-propelling rock-dusting machine within 50 feet of the face of No. 2 butt parallel before they examined for gas. The machine operator found an accumulation of explosive gas about 13 inches from the roof. He began to wave his arms thoroughly mixing the gas and air. Undoubtedly a highly explosive mixture was created, and as the men attempted to run the machine back to fresh air as explosion occurred.

Jan 1, 1927

By S. Kelkar, H. Murphy, Z. Dash

Nearly 30 estimates of the minimum earth stress were obtained from hydraulic stimulation tests in 5 boreholes at depths varying from 0.6 to 4.3 km in jointed granitic rock near the Valles Caldera in New Mexico. This site is located within the transition between the Colorado Plateau and Basin and Range provinces. Stresses were determined from open hole hydraulic fracturing experiments conducted with water at pressures up to 48.3 MPa (surface). The virgin bottomhol e temperatures ranged up to 327°C. Pressure records show no evidence of rock breakdown, indicating injection into pre-existing joints. A typical pressure response consists of an early wellbore storage period followed by linear fracture flow, which then evolves into a steady pressure, fracture extension mode. Shut-in behavior is characterized by a sharp pressure drop followed by a more gradual decay. The minimum earth stress shows a general linear trend with depth, increasing with a gradient of 19 MPa/km. A low stress anomaly occurs from 2490 to 3100 m where the minimum stresses are as much as 28 MPa lower.

Jan 1, 1986

By Matthew J. Hrebar

SINCE the first installation in 1936, the use of rubber-tired equipment for secondary mine haulage has increased rapidly. From August 1936 to January 1944, approximately 750 rubber-tired units were placed in operation. Of these, 650 units were installed after January 1940. During the year 1941, it per cent of the mobile loaded bituminous tonnage was hauled by rubber-tired equipment. This percentage increased to about 20 per cent during 1943. The first rubber-tired units were battery-powered tractor-trailer types. In the year 1938 the battery-powered self-contained car was introduced. In 1939, the cable-powered self-contained car made its appearance. These self-contained units are our modern "shuttle cars." By the end of 1941, approximately 15 per cent of the shuttle cars in operation were cable-powered. Installations made during 1942 and 1943 increased the proportion of cable-powered cars to about 40 per cent of the total number of shuttle cars in use. There is a marked trend toward cable-powered cars, although one need not make many trips to mines where both types are used to discover that opinions are highly controversial as to the relative advantages and field of use of each type. It is natural for mining engineers in the coal-mining industry to have diversified opinions regarding the use and application of coal-mining machinery. Coal mining is not a standardized industry; natural conditions vary from mine to mine. However, it is surprising how many operations in scattered fields arrive at the same conclusions and adopt similar methods. This happens not so much through cooperation and exchange of ideas as through hard, costly experimentation, involving months of low production and relatively high costs. What then, are the reasons for increased use of cable cars? Could it be that present scarcity of materials is forcing their use? True, battery cars require considerably more auxiliary equipment, but during 1942 it was no more difficult to obtain than shuttle-car cable. Furthermore, the trend toward cable cars started before curtailments on mining equipment took effect. Undoubtedly, cable-reel shuttle cars were introduced to produce coal at a lower cost by simplifying trackless mining through the elimination of auxiliary equipment, and by reducing the first cost on equipment. The theory of cable-powered shuttle cars is well based, as can be proved by successful operations. Many operators have weighed the advantages and disadvantages of each type carefully before choosing the type most suitable to their operation. Others have taken much for granted and accepted one or the other without much thought. At many small operations, low first cost is apt to be the deciding factor. One large company, with considerable experience in the use of battery locomotives, preferred to use cable cars even though it was neces¬sary to reduce the section voltage from

Jan 1, 1944

By G. R. Dunning, M. R. Wilson

"Abstract - The early Paleozoic accretionary tectonic regime that was established along the Laurentian margin of the Newfoundland Appalachians provided a favorable setting for shear-hosted gold mineralization along a major terrane suture, the Baie Verte-Brompton Line. The Stog’er Tight prospect is one of several mesothermal-style gold occurrences hosted by shear zones within accreted ophiolites and oceanic arc terranes on the Baie Verte Peninsula. It is an epigenetic, stratabound deposit that is confined to shallow-level gabbro sills within the volcanic cover sequence of the allochthonous Point Rousse ophiolite complex. Gold mineralization at Stog’er Tight is associated with hydrothermal mineral assemblages represented by chlorite-calcite, sericite-ankerite, red albitepyrite (±Au) and chlorite-magnetite alteration zones. Gold occurs with pyrite within the intensely altered gabbro, along the margins of syn- to late-shear, quartz-rich, replacement veins.The Stog’er Tight gabbro served as a rigid body conducive to shear deformation and fluid penetration, whereas, its high Fe-Ti oxide content induced fluid oxidation and gold-pyrite precipitation. Hydrothermal alteration involved progressive CO2, S, Na, and LILE metasomatism, along with significant enrichments in the REE, HFSE, and Th in the high-grade ore zone. Temperatures of vein formation and alteration are constrained by oxygen isotope thermometry to be between 250°C and 480°C. Isotopic compositions of vein quartz from the Stog’er Tight prospect are uniform (??O = +12.5 ± 1‰) and fall within the range cited for many shear-hosted, auriferous quartz veins.A U-Pb zircon igneous age of 483 +3/-2 Ma for the Stog’er Tight gabbro is consistent with its stratigraphic correlation with other Ordovician ophiolitic and volcanic arc/back-arc assemblages in Newfoundland. The U-Pb age of a rare variety of hydrothermal zircon recovered from the high-grade ore zone directly constrains the timing of gold mineralization to 420 ±5 Ma, in accord with a major orogenic episode of Silurian age that produced many of the magmatic and metamorphic rock suites in north-central Newfoundland. Our results are consistent with a post-peak metamorphic, late-magmatic model for gold mineralization that occurred during the waning stages of Silurian orogenesis, driven by emplacement of I-type granitoid intrusions into the crust."

Jan 1, 2000

By Gary N. Weinrich

Large surface mining projects in sparsely populated regions of the West have the potential to create disruptions in an area's social and economic character with potential effects on man that can far outweigh the physical and ecological effects on man's environment. The data and analyses involved in addressing the socioeconomic issues are additional to those traditionally associated with surface coal mining, such as those concerning land reclamation and water quality. Appropriate socioeconomic studies in conjunction with mine-planning can identify the potential problem areas in order that project measures can be taken to maximize the beneficial impacts and minimize the adverse effects of surface coal mining. The information required to conduct such socioeconomic analyses, available data sources, and the applicable analyses are described. Overall impacts of some proposed Western surface mines are summarized and potential mitigating steps discussed.

Jan 1, 1975

By Roger Lafrance

"This paper discusses various aspects affected by the use of large-diameter boreholes in underground mines. Topics covered consist of noxious fumes, vibrations, post-blast effects, various types of explosives, the cordine system in production blasts, the slider primer system and wall-control methods. In general, the paper is an overview of this important fact of underground mining.IntroductionWith economical factors leading the way, many reasons motivated drilling equipment companies to develop equipment that can drill holes up to eight inches in diameter and even larger for underground applications. One of these other reasons is the fact that many orebodies were considered marginal, given the high costs of conventional mining methods utilizing small diameter boreholes. With these criteria in mind, accelerated programs were put in motion to develop equipment that would reduce both-development and production costs in underground mines. Change s in any basic program often affect other areas down the line. This is particularly true with the ad vent of large-diameter boreholes underground.C-I-L Inc. is certainly no stranger to this phenomena. Whether production headings increase in size and tonnage or whether production increases due to lower costs, one fact remains unchanged and that is the fact that all development and production holes are loaded and blasted whether they be of small or large diameter. Due to this fact, C-I-L Inc., as a leading explosives manufacturer, initiated a program to examine blasting methods in use in surface work with the intent of revising these method s for underground applications. Research facilities were also oriented toward developing appropriate products. This was a task that was accepted with anticipation, with the result that many new blasting systems and methods were brought forward, thanks to the collective efforts of both the consumers and manufacturers."

Jan 1, 1984

By G N. Phillips

No new goldfields have been found in the Witwatersrand Basin for over 60 years, and one consequence of this is a long-term decline in gold production. Exploration throughout this period has been based on the placer model that infers alluvial transport of gold grains and then sedimentary sorting in the basin; however, there is no viable source for so much alluvial gold and no single sedimentary setting that hosts the gold.An alternative genetic model can now provide a quantified explanation for the source of the gold, and it does not rely on alluvial gold processes. The hydrothermal model can easily explain the source of the Witwatersrand gold as being derived from the background gold at parts per billion (ppb) level throughout the Kaapvaal craton of South Africa. This gold is involved in metamorphic processes, available for solution in metamorphic fluids, and hence may be transported whilst dissolved in fluid into the Witwatersrand Basin. The hydrothermal model warrants consideration as it can explain the source of gold, the large alteration halo in the goldfields, the mineralogy, and especially the gold-carbon association.Working on the premise that if one model (placer) is not giving the desired results (discovery of new goldfields), then it may be prudent to consider alternatives. Application of a hydrothermal model to guide exploration would place importance on large and small early structures in and around the Witwatersrand Basin; it would also emphasise the geochemical nature of potential host rocks (especially C and Fe) rather than their sedimentary origin.CITATION:Phillips, G N, 2013. Origin of Witwatersrand Gold - a viable source region and source process for gold, in Proceedings World Gold 2013 , pp 175-180 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By T Mizuta, T Nakano, D Ishiyama

The Tamagawa Hot Spring, from which Ra-Pb-Sr-bearing barite precipitates, is a representative hot spring in a volcanic gas-bearing hydrothermal system associated with Quaternary andesitic to dacitic magmatic activity beneath the Yakeyama Volcano. Thermal water in the Tamagawa Hot Spring is divided into three types: Cl-SO4-type (Ohbuki hot spring: pH 1.2); SO4-type (pH 1.8 to 2.9); and neutral-type (pH 6.1). The concentrations of dissolved components in the Ohbuki Cl-SO4-type thermal water are about ten times higher than in the SO4-type thermal water. The 87Sr/86Sr isotopic signatures of the Ohbuki Cl-SO4-type thermal waters (0.703992 ¦ 0.000004 to 0.704032 ¦ 0.000006) are different from those of SO4-type thermal waters (0.704245 ¦ 0.000003) formed by the interaction of andesitic volcanic rocks (0.704065 ¦ 0.000007 to 0.704093 ¦ 0.000009) and groundwater derived from river water (0.704314 ¦ 0.000012 to 0.704519 ¦ 0.000013) in a shallower part of the hot spring area. The possible origins of Sr in the Ohbuki Cl-SO4-type thermal water and in the SO4-type thermal water are different. The Sr isotopic ratios (0.704130 ¦ 0.000012 to 0.707556 ¦ 0.000014) of Aniai Formation andPreYakeyama Lake deposits occurring below the hot spring area are distinctly higher than those of the Cl-SO4-type thermal water. However, it is expected that a solidifying andesitic or dacitic magma which has similar Sr isotopic ratios of the Ohbuki Cl-SO4-type thermal water, occur in the deep portion of the Tamagawa Hot Spring. The Cl-SO4-type thermal waters having low Sr isotopic ratios do not acquire their Sr isotopic signatures by interaction with strata below the hot spring area, but they are likely to reflect water interaction with a solidifying magma with low Sr isotopic ratios. Components including rare metals in Cl-SO4 type thermal water could be transported from a deeper part. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By P M. Bradbury

The nature of aggressive process chemical requirements typically in the Platinum Refinery Industries, lend themselves to the use of Polymer Composite Glass Reinforced plastics for pipework and other associated equipment in these types of Plants. This paper discusses the basic characteristics of a Polymer Composite glass reinforced piping system and gives sample examples of applications in current present day use.

Jan 1, 2006

By M. D. Everell

A study has been made of the relationships between grinding selection functions and physical properties of rocks, particularly the failure loads of irregular particles and the compressive and tensile strengths of large regular specimens. The rocks used were limestones of various structures and impurity contents, a carbonatite, and a high-purity crystallized calcite. The selection functions were obtained from carefully performed grinding experiments on selected narrow size ranges in various grinding machines-a laboratory batch ball mill, a Hard grove grindability machine, and a mill of the type suggested by Yang, Mempel, and Fuerstenau. The specific rates of breakage during milling and the failure loads of irregular specimens correlated well for the rocks studied. The testing of irregular particles is suggested as a means of predicting the behavior of commercial mills.

Jan 1, 1973

By P. Schilizzi, A. Jarosz, M. Karmis

This paper is concerned with subsidence prediction methods and in particular with two techniques, one based on profile functions and the other on influence functions. Profile function methods provide a tool for a fast calculation of subsidence on a line across a mine panel. Influence function methods, on the other hand, allow for a more detailed calculation of ground movements, in any mode and at any depth, on a grid or at any specific point. In more detail, the hyperbolic tangent profile function, as developed by VPI&SU from field data pertaining to the eastern U.S. coalfields, and an influence function method currently being adapted for the same region, are presented and discussed. The applicability, advantages and limitations of these techniques are examined and comparisons are presented with field measurements. Computer software developed for the application of these prediction methods, for two widely used personal computer systems, are also discussed and a number of examples are presented demonstrating the potential of such programs.

Jan 1, 1986

By Kenneth L. Adams

10.3-1. Introduction. Equipment replacement or maintenance is of major concern to every company today. It can be the difference between an efficient and profitable operation or an inefficient and struggling one. Mining equipment, as everyone knows, will not last forever. Some equipment becomes obsolete before it wears out while some may be doing its intended job, yet not economically. It is a major problem for management to make the decision as to whether a piece of equipment should be repaired or replaced. There are numerous approaches to this problem; using formulas, charts, and graphs. These would be very good if all conditions were stable. Since conditions and requirements are constantly changing, an accurate observation cannot be derived from a set formula. A formula does, however, serve as a reminder to include most of the items that should be considered when evaluating old and new equipment. In the field of mining there are several questions which enter into the reasoning that are difficult to put into an equation. Some of these are: 1. Will the present equipment produce the required output of the mine, or an increase if necessary? 2. Are reserves adequate to support the purchase of new equipment? 3. Can the old equipment be repaired to efficiently continue the mining operation? 4. What is the stability of future markets for the product? Depreciation rate, or the write-off life, is a factor that can directly effect decisions on replacement. If the initial life expectancy is too long and the price of equipment is not written off when discarded, then the original investment has not been recovered. If the write-off time is too short, then the equipment is written off before replacement is even considered. In this case, the depreciation accrual is usually used to finance some other phase of the operation. In view of the increasing prices, the amount of depreciation fund is generally too small for much incentive to replace an older unit

Jan 1, 1968

By R. E. Hucko

Introduction The principal thrust of the US Department of Energy (DOE) coal preparation R&D program is to develop technology to reduce ash and sulfur content of US coals to levels where the resultant product can be formulated into a high quality solid or slurry fuel that could replace oil or natural gas in both new and retrofit applications. The coal preparation program is implemented by the Pittsburgh Energy Technology Center (PETC) and is conducted both in house and by a cross section of industrial organizations, universities, and national laboratories. Research is subdivided into three areas - coal characterization, beneficiation, and ancillary unit operations.

Jan 1, 1985

To date Iron Monarch is the most important Australian source of iron ore and since HH5 has produced about 84 million tons of direct shipping ore containing 62 per cent iron and 3 per cent manganese.Previous geological work, mainly by Rudd, Edwards and Miles is reviewed and the results of later exploration by quarrying and drilling are discussed and modified interpretations of both stratigraphy and structure are advanced. Renewed study of the mineralogy of the iron ores is advocated.The Iron Monarch orebody lies on the up-thrown side of a major transcurrent fault that truncates it on its northern boundary. The nearby Iron Knob orebody is believed to occupy a horizon that is some thousand feet stratigraphically above Iron Monarch.The origin of the ore cannot be explained by any simple theory; development probably took place over a long period of time from Lower Palaeozoic to Tertiary.INTRODUCTIONIron Monarch orebody has supplied the Australian iron and steel industry with the greater part of its ironstone requirements since the establishment of the Newcastle steelworks in 1915. Annual production of direct-shipping ore has exceeded three million tons but declined slightly after 1956 when Iron Prince was brought into production. Total production of ore from Iron Monarch to the end of 1962 is about 84,000,000 long tons containing some 55,000,000 tons of metal.The deposit (Lat. 32°44'30"S : Long. 137°08'30"E) is 34 miles north-west of Whyalla, on the western shore of Spencer Gulf. A 42 in. gauge railway connects Iron Monarch and its associated small town of Iron Knob with Whyalla (Fig. 1).For the purpose of this paper Iron Monarch includes Iron Knob and the intervening jaspilite hill known as Substation Ridge, and the description of the general geology necessarily 'Assistant Chief Geologist, The Broken Hill Proprietary Co. Ltd.This paper was presented at the Annual Conference of The Institute, 14-24th August 1968.

Jan 1, 1964

EXECUTIVE COMMITTEES OF LOCAL SECTIONS New York LOUIS D. HUNTOON, Chairman. ARTHUR S. DWIGHT, Vice-Chairman. THOMAS T. READ, Secretary, Woolworth Bldg., New York, N. Y. E. MALTBY SHIPP, Treasurer. GEORGE F. KUNZ, W. DE L. BENEDICT. Boston ROBERT H. RICHARDS, Chairman. ALBERT SAUVEUR, Vice-Chairman. AUGUSTUS H. EUSTIS, Secretary-Treasurer, 131 State St., Boston, Mass. TIMOTHY W. SPRAGUE, HENRY A. WENTWORTH.

Jan 2, 1914

THE CHAIRMAN (H. W. MORSE, Los Angeles, Cal.).-I would like to open this meeting for a little while to the general subject of leaching. We ought not to hold back if we have any new schemes for the future. I know that those of us who are tangled up with this lei thing work will appreciate any suggestions that will make us work harder and, scheme, harder to pull through these past difficulties on leaching. F. S. SCHIMERKA, Clifton, Ariz.-Under the direction of J. W. Bennie, General Manager of the Shannon Copper Co., Clifton, Ariz., 'it has been my valued privilege to cooperate in the elaboration of a hydrometallurgical process aiming at the recovery of copper in mill tailing resulting from a gravity concentration of a low-grade semi-oxidized sulphide ore occurring in a porphyritic gangue. The experimental work which has been carried on with a 25-ton plant is completed, and the company is building at present a leaching plant on a larger scale, the first unit consisting of a 150-ton roasting furnace and accessories for leaching the calcine.

Jan 12, 1916

Residential and commercial plumbers in the United States were introduced to Viega?s copper press technology in 1999. In short, the technology allows plumbers and installers to join copper pipe securely in four to seven seconds on pipe sizes of 1.2 to 10 cm (0.5 to 4 in.) by pressing the connections with specialized tools and fittings rather than through sodering or welding. The water- and air-tight technology, first introduced in Germany in 1989, includes three different sealing elements, a variety of materials and a selection of configurations. By eliminating the need to thread or solder pipe, connections and repairs can be made quickly and securely. Installations are also much quicker and as secure as traditional methods.

Jan 1, 2012

By C. Hari Manoj Simha, J. Gholipour, M. J. Worswick

Due to the high pressures involved in the hydroforming process, friction and lubrication play an important role and can affect formability of the material. Tubes of A1Mg3.5Mn aluminum alloy, of 76.2 mm (3 inch) outside diameter and 2-mm thickness were considered in this study. Three kinds of lubricants, Al070, Hydrodraw711 and water, were applied to the tubes and tubes were hydroformed to burst in a square shape die cavity. The key process parameters were recorded during the tests. An in-house Gurson-Tvergaard-Needleman (GTN) damage-based material model, implemented in LS-DYNA, was used to model the process and predict the formability of this material. The applied axial loads and internal pressures recorded during the tests were used in the computations. The effect of different types of elements (solid and shell) with different constitutive models (von Mises and GTN models) in predicting the strain distribution is studied. The GTN damage-based material showed a good ability to capture necking and displacement histories in this process. Both predicted and measured results showed that the lubricant with lower coefficient of friction can effectively increase the comer expansion.

Jan 1, 2006

By G. E. Viens, R. A. Campbell, G. N. Banks

A survey of the literature reveals wide differences in the procedures used in making iron ore pellets and in the properties of the pellets obtained. In this paper, the methods of production and the properties of pellets, as reported in the literature, are examined in an effort to determine what correlations exist between them. An attempt is also made to determine the levels of the properties of pellets which are considered acceptable and desirable in modern practice. M UCH has been written regarding the important changes which have been taking place recently in the iron ore industry. As the demand for ore has increased and the supply of direct-shipping ore has dwindled, tl1e problems associated with the utilization of lower grade ores ha\•e been intensely investigated and important advances in both beneficiation and agglomeration techniques have taken place. In particular, there has been a great deal of activity in connection with the pelletizing method of agglomeration. The superiority of pellets over raw ore has been demonstrated in blast furnace tests

Jan 1, 1962

The paper describes the progress made in the last decade with the introduction of comprehensive monitoring of the mine atmosphere into U.K. collieries. Brief descriptions are given of the various portable and fixed point instruments which have been developed for this purpose and the methods available for transmission of information to the surface are also discussed. The paper also outlines some of the research work being carried out both in the laboratory and underground on the development of alternative methods of fire detection. Some of the results from this work are illustrated and discussed.

Jan 1, 1981