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By Paul Averitt

The coal-bearing rocks in Iowa occur in an arcuate belt across the central and southern parts of the State (fig. 1) at the northern end of the Western Interior coal field. Coal beds of minable thickness are sporadic throughout this area and are mined principally in the three districts indicated by dark shading on the index map, although coal occurs also in the areas indicated by light shading. The coal is mostly of high-volatile C bituminous rank in all parts of the State. SURFACE FEATURES The coal-bearing rocks in Iowa are concealed for the most part by a covering of glacial drift ranging in thickness from a few feet to several hundred feet. This covering has been dissected to form a gently rolling upland, rising from an elevation of 466 feet at the mouth of the Des Moines River to about 1,200 feet in Calhoun County in the central part of the State. The local relief, however, rarely exceeds 150 to 200 feet.

Jan 1, 1949

By Warren H. Weisz

A cement, in the broad sense, is any substance which will cause various materials to adhere to each other. Clay was probably the first material to be used by man as a cement or binding agent. Water occurs in or is mixed with the clay to make it plastic, so that it can be formed in place. The sun and air remove the water from the clay and on drying strength is developed. The clays unless fired are not too resistant to water, therefore, their use is best when restricted to dry areas. Gypsum used as a cementitious material is not the subject of this paper, but its use dates back thousands of years. Gypsum mortars were used by the Egyptians in building such massive masonry structures as the pyramids. The Egyptian mortar consisted of a mixture of sand with burned gypsum (of an impure type of 81.5 per cent calcium sulphate and 9.5 per cent calcium carbonate) for the cementitious material. The burning of this type of cementitious material took place at relatively low temperature. These burning reactions will be covered later when the dehydration of gypsum is discussed. The setting of the partially dehydrated gypsum is considered to be crystallization from a supersaturated solution which deposits crystals of dihydrate (gypsum). In low water-content mixes, the interlocking of the needle-like crystals helps to produce higher strengths. Slaked lime made from limestone burned at higher temperatures (1648 F is generally considered as the calcining temperature, although under certain conditions incipient calcination will take place at 1250 F) is another early-period cementitious material. During slaking with water, a colloidal or amorphous hydrated lime is formed. When it is allowed to dry, it hardens and develops low strengths. On exposure to the carbon dioxide of air in the presence of some moisture, carbon dioxide is adsorbed and part of the calcium hydroxide is converted to calcium carbonate. Structures in which a lime mortar is used continue to grow in strength as this reaction proflesses. Hydrated lime has the disadvantage of not setting under water.

Jan 1, 1960

By Phillip I. Merritt

"IntroductionDuring and since• the war, it has been my privilege to work closely with those in Canada who are responsible for the vital raw materials needed in our co-operative atomic energy programme. The understanding which has developed between our two groups in this all-important enterprise has been a great source of pleasure. We in the United States are aware of the importance of the contribution made by Canada to this project, and we look forward to continuing our mutually advantageous relationship.The impact of World War II, and the decision by Canada, Great Britain, and the United States to join in a programme for the development of atomic weapons, created a sudden and immense demand for uranium minerals. Early in the raw materials programme, it was evident that sufficient raw materials to fulfill war-time atomic weapon requirements could be secured from three sources: the rich pitchblende deposits of the Eldorado , mine at Great Bear lake; the Shinkolobwe mine in the Belgian Congo; and as a by-product of the vanadium industry of the Colorado Plateau in the United States. In the early part of the programme, therefore, our joint efforts were directed toward obtaining immediate maximum production from these localities. The contribution made by Eldorado Mining and Refining (1944), Limited, both in supplying and refining raw materials, was and continues to be of vital importance.In addition, it was also obvious from the first that in this programme, as in any mining enterprise, exploration activities directed•toward the discovery and development of new sources of uranium ore were essential if production were to be maintained over an extended period of time. In order to satisfy obvious security requirements during the war, it was necessary to proceed with this exploration programme, both in Canada and the United States, as secretly as possible. With the end of the war, and the revelation that an atomic weapon had been developed, however, secrecy in exploration was no longer required. The important thing was to get on with a broadened exploration programme."

Jan 1, 1950

By D. P. R. Smyth

The limestone reef reservoir at Swan Hills consists essentially of a "buildup" of successively smaller atoll-like layers. Precipitation of calcium carbonate within the lagoonal area of each layer essentially kept pace with growth of the outer organic lattice. Within the reef mass, six de-positional environments characterized by specific suites of fossils (or fossil fragments) and associated limestone textures are recognized as follows: ( 1) Aerated moderately agitated water of normal marine salinity (widespread shelf or submerged reef-built platform). Thamnopora-type corals, Amphipora, "pancake" stroma-toporoids, crinoids, articulate bra-chiopods, rare rugose cup corals, and ostracods occurs in light gray-buff skeletal microgranular limestone of low permeability. (2) Semi-stagnant quiet water of normal marine salinity (leeward side of reef). Crinoids, articulate brachio-pods, rare thamnopora-type corals, Amphipora, pancake and bulbous stromatoporoids, rugose cup corals, ostracods and gastropods occur in impermeable dark brown argillaceous skeletal calcilutite with thin black bituminous shale beds and rare dark chert nodules.

Jan 1, 1961

By H. C. Fowler

The social economy, or public interest, and national defense require wise development and efficient use of the oil and gas resources of the United States. In this development and use, and in the prevention of economic and physical waste of oil and gas, the objectives of the petroleum and natural-gas industries, the Government (Federal, State, and local), and the public are the same. Differences of viewpoint generally have originated in the failure of one of the triad to have a clear or complete understanding of the motives behind the activities of the other component groups or full knowledge of what each is trying to accomplish. The Unites States Bureau of Mines through its petroleum and natural-gas division makes technologic and scientific investigations pertaining to recovery,3 preparation, refining, and use of oil and natural gas with the view of reducing waste, increasing safety and efficiency and aiding economic development.

Jan 1, 1933

By S. R. S. Sastri

By using the data of E.A. Hersam and F.C. Bond's equation for energy consumption in comminution, a method was developed to analyze the performance of industrial jaw crushers. The study showed that industrial jaw crushers are generally operated below capacity. The study also showed that industrial jaw crushers generally have sufficient installed power to operate at, full capacity. The method presented can be used to estimate the capacities and power requirements of jaw crushers.

Jan 1, 1995

By William S. Alldredge

The Washington Metropolitan Area Transit Authority(WMATA) officially came into existence in February 1967 after the District of Columbia, Maryland, and Virginia joined in a com¬pact pursuant to Federal creative legislation signed the previous November to build a regional rapid rail transit system called METRO (1). The parent organization was the National Capital Transportation Agency (NCTA), a Federal agency, subject to Federal statutes and regulations. Soon after the completion of the transition from NCTA to the new "non-Federal" status of the Authority, the Board of Directors of the Authority formally adopted procurement policies and procedures (2). These are specific statements concerning competition by formal advertising for bids or by solicitation of proposals for negotiation, contracting authority, approval of awards, awards of contract modifications, and processing of claims and disputes. These policies and procedures are silent as to Federal procurement statutes and regulations. But because of the Authority's origin, the sensitive nature of the compact among the several sovereign jurisdictions, Federal financing of two-thirds of the costs, and the resultant surveillance by the General Accounting Office over staff operations, the Authority's procurement practices follow closely Federal regulations adapted to WMATA's needs. This is an important point and is the foundation of contractual relations between the Authority as the owner and its construction contractors. Various constraints and flexibilities of this arrangement with respect to excavation and tunneling contracts will be pointed out in the ensuing discussions.

Jan 1, 1974

The complex organic chemicals in coal differ from those in petroleum mainly by the ratio of carbon atoms to hydrogen atoms; this ratio is about 2 for coal and 1 for petroleum. By changing the ratio, coal can be converted into compounds similar to those found in petroleum. In. very simplified form, omitting here the special conditions required, the paths by which this can be done are: [ ] Part or all of the coal is first gasified by reaction with steam and oxygen, either in a gasifier or while the coal is still in place underground. The resulting gas is mainly hydrogen and carbon monoxide, with impurities that .must be removed before further processing by one of the following routes.

Jan 1, 1959

By Eugene Guccione

The US mining industry today is fighting for its existence. We are plagued by the shortage of materials, of equipment, of fuels, of capital, of manpower. If we solve those shortages, we are then frustrated in our attempts to open a new mine or, perish the thought, a new smelter. If we manage to make a profit, demagogues will accuse us of stealing from consumers; and, if we do not make a profit and have to shut down, the same demagogues will accuse us of creating unemployment. Meanwhile, in every aspect of our business - from research, exploration and development, to production, marketing and selling - we are hindered in every way by the bipartisan mismanagement and crippling controls of a government bureaucracy gone amok. We are fighting a war on every front. Some of you realize that ours is a war of ideas. In order to win, our industry must make its ideas heard. But to be heard, we must have something to say - which means: we must know our case logically and consistently, all the way down to essential principles. A principle is a primary truth applicable to a great number of instances. A principle is like a road map: it shows you all the possible alternatives for getting from where you are to where you want to go. Although practically everybody recognizes the usefulness of a map and the need to consult it to find the best way' to get from one city to another, most people are not as careful in charting the course of their life, or the course of their industry, or the course of their nation. And so they act blindly, at random, by the whim of the moment, and get nowhere fast.

Jan 1, 1975

By Silvio Hernández Aquije

El presente texto señala el descubrimento del yacimiento vanadífero de Minasragra a través del reporte de Yeatman-Berry en 1916 y el de Kett-Sproul en 1931. Así también señala los tipos de mineralización como la mineralización primaria y por impregnación.

Jul 1, 1955

By D. C. Seidel

This report describes generic procedures and equipment arrangements for conducting laboratory-scale hydrometallurgical and related waste-management experiments. It provides a starting point for personnel who have received or are receiving professional training, but do not have specific experience in laboratory procedures. With guidance, it also has application as a resource for technician training. The publication contains chapters on laboratory safety, feed-sample preparation, leaching, solids-liquid separation, and recovery from solution.

Jan 1, 1995

By R. C. M. Minnitt, W. Dr. Assibey-Bonsu, F. A. Camisani-Calzolari

Born in Bothaville (OFS) on the 26th August 1919, Daniel G. Krige grew up in Krugersdorp on the West Rand. Hematriculated from Monument High School in Krugersdorpin 1934 at the age of 15 and graduated with a B.Sc. (Eng.)degree in mining engineering from the University of the Witwatersrand at the end of 1938 (age 19). In 1938 he joined Anglo Transvaal where he worked on a number of gold mines until 1943, gaining a wide range of valuable practical experience in surveying, sampling and ore valuation. He then joined the Government Mining Engineer’s Department where he worked for 8 years during which time he participated in the uranium negotiations with the British and American authorities and designed the uranium pricing formula for the contracts which led to the establishment of South Africa's profitable uranium industry in the early 1950s. During the same period he began his pioneering work in the application of mathematical statistics to the valuation of new gold mines using a limited number of boreholes and of ore reserves for existing mines. His early papers in the application of mathematical statistics, some republished in French, created world-wide interest that led to the development of the science and concepts that surround the spatial evaluation of mineral resources and reserves known as geostatistics. This technique has contributed to improved ore evaluation techniques as well as the reduction of the financial risks associated with investment in mining enterprises. Furthermore, it led to the recognition of his contributions to the evaluations of mineral deposits through the coining of the term ‘kriging’ that is used to describe a spatial mineral evaluation process known and practised in international mining circles. He continued his work in geostatistics throughout his career as Group Financial Engineer of the Anglovaal Group until his retirement in1981 and afterwards for ten years as Professor of Mineral Economics at the Witwatersrand University. He is still active as a consultant and is a registered Professional Engineer. He has published some 90 technical papers both locally and overseas, some in Russia, and has lectured and participated in international congresses in many countries. His contributions were recognized by the Witwatersrand University through the award of the D.Sc. (Eng.) degree in1963, by three honorary degrees (from the universities of Pretoria, UNISA and Moscow State Mining University), by many awards from the South African Institute of Mining and Metallurgy, the International Association for Mathematical Geology, Die Suid Afrikaanse Akademie vir Wetenskap en Kuns, the SME of the American Institute of Mining Engineers, the International APCOM Council in1999, the University of Antofagasta in Chile, and by the South African President (Order for Meritorious Service, Class 1, Gold). He has served on various Government committees, notably that for State Aid for gold mines (1967/8) and designed the State Aid formula which enabled many mines to survive a period of low gold prices; also various taxation committees, and the mining mission to Iran in 1974. He is a fellow and/or honorary life member of various technical societies locally and overseas, including the Royal Society of South Africa. During the period in the Government service he also handled several of the post-war lease applications in the Free State and Klerksdorp goldfields. The fact that decisions on new gold mines of critical importance to the State and the economy as a whole, were being taken on a limited number of drillholes without any scientific analysis of the risks of failure, stimulated him to start basic research into ore evaluation. His approach was based on the application of Mathematical Statistics to these problems, an approach of which very little was known world-wide at that stage but which had already been initiated in South Africa by Sichel via the lognormal frequency distribution model. In Krige's 1951 paper published in the Journal of the Chemical, Metallurgical and Mining Society of South Africa he covered the statistical explanation of the conditional biases in ore block valuations and stimulated the use by several gold mines of regression corrections for routine ore reserve valuations, a technique which, in effect, was the first use on an elementary basis of what is now known as kriging. His 1952 paper introduced, inter alia the basic geostatistical concepts of ‘support’, ‘spatial structure’,’ selective mining units’ and ‘grade-tonnage curves’. His 1951 paper was based on his M.Sc. (Eng.) thesis submitted in the Department of Mining Engineering to the University of the Witwatersrand, and expounded his pioneering work in geostatistics in more detail. His early research papers that had stimulated interest in several mining circles overseas, were republished in French in1955, resulting in a major research effort by French mining engineers in this field. This, in turn, led to the establishment of the now world-renowned French school of ore evaluation in Fontainebleau, Le Centre de Geostatistique de l’École des Mines de Paris. As the Group’s Financial Engineer at the Anglovaal Head Office until his retirement in 1981, he was responsible for

Jan 1, 2003

By William R. Barton

Dimension stones, with their almost infinite variety, have a broad range of properties and uses. Natural stone was beyond doubt the first mineral commodity used by man. Today dimension stone has widened to encompass building exteriors and interiors, decorative and ornamental modes, statuary, monuments, paving, curbing, flagging, roofing, and miscellaneous categories such as blackboards, surface plates, and honestones. For many purposes, it competes with greater or less success with alternate materials such as concrete, metal, brick, plastic, or glass. The almost ubiquitous geographic distribution of stone resources is the basis for a dimension stone producer industry in almost every State and in almost every land. In the United States, alone, dimension stone sold or used by quarries is valued at 2 million to 3 million dollars annually. Mining, finishing, transportation, and use technology have been modernized, resulting in a broader spectrum of stone products and new adaptions in use. Increased efficiencies also have been reflected in costs and prices and, coupled with gains that should be realized from current research, auger well for continued vitality of the ancient and honorable dimension stone craft.

Jan 1, 1968

By D. Harrington

The mining industry of the United States has-long been severely criticized because of its high rate of accident occurrence, net only as compared with other major industries-in the United States but also with the mining industries of other countries particularly Europe. Statistics (often not of strictly comparable nature) indicate that the accident-frequency rate in all mining is currently about three times and the accident-severity rate is about seven times as great as the average for general industrial work in the United States. These figures are by no means comforting to humanitarian mining men, irrespective of their status in. the industry, and they constitute a challenge that certainly cannot continue to be ignored much longer. This picture becomes much darker when the above statistics are augmented with data indicating that. on an exposure basis our mines (more particularly our coal mines) have accident rates two, three, or even more times as great as more or less similar types of mines in Europe, particularly England and Wales, Belgium, France, and Germany. However, these foreign accident statistics should be carefully analyzed before we become very mush concerned about them, because they are clot strictly comparable owing to several considerations, not the least of which is the fact that foreign methods of compiling or recording accident statistics often differ materially from ours. Moreover, foreign mining and other conditions axe definitely dissimilar to ours in many if not most phases, and numerous ether factors affect the comparability of foreign mine-accident statistics with ours. Unquestionably it should also be taken into consideration that the accident rate of the 130,000,000 or more constituting the populace of the United. States as a whole is much higher than that of any other major country in the world and is two, throe, or more times the rate of the European countries that have more favorable mine-accident rates than those of the United States. Moreover, it is significant that the mine-accident-severity- rate of British mines is about six times the average accident-severity rate of the major industries of the British Isles, or but little mere, favorable than the comparable figures in the United States, namely, that mining-has an accident-severity rate about seven times that of the average of about 30 of the major industries of this country.

Jan 1, 1941

By David Mast, Irwan Halim, Seung Han Kim

Nowadays more infrastructure tunnel projects are procured using design-build method. In this environment, the Owner’s engineer would typically provide performance requirements for the design-builder, and the Contractor’s designer would work with the contractor to design the tunnel lining based on the Contractor’s means and methods and manufacturing process. This paper will describe the typical requirements provided by the Owner based on its design objectives, and the means and methods by the Contractor that would significantly impact the design. Project examples and recommendations for Owner’s requirements will be provided that can optimize the design and still achieve the Owner’s performance objectives.

Jun 13, 2021

By S Worden, A Lee Zhi Yi, E Sellers, G Corder, A Littleboy

The global shift towards decarbonisation is driving competition for the extraction of critical minerals such as nickel, lithium, and copper. To meet this demand, new mines are being developed while mines approaching closure are being reimagined as sites of potential resources. This reimagining challenges how mine closure is being conceptualised. In the conventional case, when a mine reaches the end of its economic life, it is closed or put into care and maintenance until it transitions to the next land use, such as agriculture, native ecosystem corridors, solar farms or integrated eco – precincts (Murphy et al, 2019; Holcombe, 2020) (the authors acknowledge that unplanned mine closures have left a devastating legacy of contamination, safety and cultural heritage impacts). Extracting minerals from closed or closing mines will extend mine life and, therefore, delay relinquishment and transition. In this context, innovative technologies are needed to make mining economically viable. In the first year of her doctoral research on improving stakeholder engagement in mine transitions, Lee Zhi Yi has coined the term ‘mine life extension technologies’ (MLETs) to describe a class of technological solutions that optimise extraction of resources after a mine reaches the end of its economic life. Examples of MLETs include agromining (van der Ent et al, 2015), in situ recovery (Robinson and Kuhar, 2018), and reprocessing or reuse of tailings (Gou, Zhou and Then, 2019). MLET extraction offers several benefits compared with conventional mining processes, such as waste remediation, value recovery of minerals, a smaller footprint and less environmental impacts (Sellers, Picorelli and Salmi, 2022). What requires further investigation is the consequences of MLET implementation to host communities or community perspectives towards the proposed technology and subsequent delays in transition.

Aug 2, 2023

By Frank L. Hess

"New England" and "granite" if not synonymous are at least associated terms. Where there are granites that are not deeply eroded there are usually pegmatites, the most erratic of rocks, and of them New England has a full portion. Many of the New England pegmatites contain the rare alkalis - lithium, rubidium, and cesium. however, the same in homogeneity of the earth's crust that has made the New England pegmatites unusual, in that so many of them contain the rare alkalis, has likewise made the distribution of the rare-alkali minerals sporadic even in those pegmatites, and most contain only enough to furnish collectors with more or less ornamental and uncommon minerals. New England has long had numberless collectors of minerals, and the mineralogists of its various schools have published many papers on the pegmatitic minerals, including those of the rare alkalis, but none of the papers have dealt with estimates of quantities. In this paper we have tried to place the emphasis on quantity rather than on mineralogy.

Jan 1, 1943

By D. Pennington

Ground-water levels and subsidence have been monitored over a longwall panel of a deep coal mining operation located in western Pennsylvania. The monitoring network includes eleven ground-water monitoring wells completed to measure water level changes in separate shallow and deep aquifer zone-, and 50-foot surveyed subsidence stations parallel and perpendicular to the panel centerline. Monthly monitoring data were collected during the premining, mining, and postmining tine periods. Aquifer testing and borehole geophysical logging were conducted during premining, and post-mining conditions to document any changes in aquifer properties and ground-water flow patterns. Results indicate ground-water declines were located with respect to the mining face and mined longwall panel. Dewatering of the deep aquifer zone caused a significant water level decline in deep wells; however, the shallow aquifer zone was isolated fro major impacts by an aquitardal layer during, the, one-year period. Transmissivity data were greatly impacted by fracturing, in the highly anisotropic aquifer system. Borehole geophysical logging indicated changes in ground-water flow patterns and zones of increased fracturing from subsidence.

Jan 1, 1984

By G. F. Kuncir

This volume was prepared in support of an evaluation of the Advancing Oil Shale Mining Technology Program performed by The Aerospace Corporation under a Bureau of Mines contract. The evaluation is described in part within a companion volume entitled Benefit-Cost Analysis. The economic mine models outlined herein provide a quantitative basis for the assessment of program benefits. Reference is made to estimated oil shale mine costs to delineate the beneficial impacts that can be expected to accrue for the future implementation of program developed technology. Estimated mine cost data are provided for surface, underground, and modified in situ oil shale mining operations.

Jan 1, 1977

By F. F. Aplan

Though over 100 minerals are known to contain the rare earth (RE) or lanthanide elements, only a few provide the bulk of the world's source of these elements. The principal RE-containing mineral, monazite [(Ce,La,Th,Y)PO4], is recovered by gravity, magnetic, electrostatic and flotation concentration methods, while the other important source mineral, bastnasite [CeFC03], is concentrated by flotation. The processing of the lesser important source minerals is discussed, as is the recovery of the lanthanides from apatite [Ca5(P04)3(F,OH)] where the rare earth elements are present from trace amounts to over 10% as the mixed oxides.

Jan 1, 1989