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Evaluation of Grinding Medium Wear in Stirred Mills The standard fine grinding machines in the minerals industry are stirred mills whose performance largely depends on the competency of the grinding medium. Medium wear in stirred mills is one of the key parameters for medium selection. A wear evaluation methodology is developed and applied in this paper to measure the wear rate of river sand using a laboratory batch stirred mill. The procedure is demonstrated by testing the sand medium in a 0.55 kW batch stirred media detritor (SMD). The sand wear rate determined in the laboratory batch mill is successfully scaled up to that determined on a full-scale Metso 355 kW SMD mill.

Sep 13, 2010

By T P. Fischer, S N. Williams, N C. Sturchio

Chemical and isotopic analyses of fumarole gases from Galeras Volcano, Colombia provide significant insights into the origin of volatile components in the magma. Water comprises a mixture of magmatic (rock-equilibrated at high temperature) and meteoric, with the relative proportions varying through time. Carbon isotopes are most consistent with a mantle source, although other contributions to the system cannot be ruled out. Nitrogen most likely originated from organic matter in subducted oceanic sediments. All of these 'primary' components have been modified somewhat by interaction or exchange with other reservoirs during ascent to the surface. In addition to information on the origin of the gases, these data show significant temporal variations precursory to eruptive events. Chemical ratios change and water becomes more meteoric in character prior to eruptions.

Jan 1, 1995

When a thin film of volatile matter is deposited under vacuum on a polished coal surface, and the coated surface is examined microscopically in plane-polarized reflected light, colour changes are observed which are characteristic of the various macerals present. The colour changes appear to be mainly due to interference between light reflected at the upper surface of the film and at the film!coal interface. A variety of source materials for the volatile matter required have been tested, including powdered bituminous coal, coal tars, boron oxide, and certain resins. Bituminous coal gave the best results.

Jan 1, 1970

Much interesting data on cemented carbides has been published over a period of years which, when classified and pieced together, gives a clear picture of this special branch of powder metallurgy. This is an attempt to present the essential information in an ordered account.THE HARD CARBIDES-THEIR PROPERTIES AND PREPARATIONThe so-called hard or refractory carbides are the carbides of a number of metals which are grouped together in the Periodic Classification. These metals are in groups IV, V and VI. They are titanium, vanadium, chromium, zirconium, niobium (columbium), molybdenum, hafnium, tantalum and tungsten. These carbides have attracted the attention of chemists because of their remarkable properties. They possess very high melting points, and are rather difficult to prepare in the pure state. Their outstanding propertyis their extreme hardness, which they share with certain other carbides, such as those of silicon and boron. In addition, these compounds possess distinctly metallic properties, such as lustre (in fused specimens) and high thermal conductivities.(l)t They are capable of forming alloys in two ways:1. With metals, particularly those of the iron group. 2. With each other (a case of solid solubility).The constitution of these substances is not that of ordinary salts, which obey the usual valency rules, but must be likened to that of certain intermetallic compounds. Actually they are "interstitial" compounds(2), that is, they are formed from the ordinary metallic lattice by the insertion of the relatively small carbon atoms in the interstices.. The energy required to fill the lattice completely is high, and this explains the difficulty often found in obtaining the exact stoicheiometric compound. Thus the carbides can have a range of composition, and can be considered as solutions of carbon in the respective metals.Physical Properties of the CarbidesThe hardness of these compounds is so great that it is difficult to compare the individual compounds on this basis. Becker(l) gives values on Moh's scale, which are not very accurate and are of no great value. Burden(3) has reproduced a diagram by Hatfield which indicates that the cemented carbides are between 1,400 and 2,000 on the Vickers diamond scale. However, the pure carbides are harder, tungsten carbide being about 2,200. Hoyt(4) describes a method of measuring hardness applicable to powdered specimenswhereby the powder is rubbed on a standard block of cemented tungsten carbide under standard conditions, and the rate of wear is determined. In...

Jan 1, 1942

By E. P. Youngman

The basic mining law of Netherland India is contained in N. I. Statute 1899 , No. 214 , as amended by N. I. Statute 1910 , No. 588 , and 1919 , No. 4 , which is quoted as the " Indian Mining Law, " the effective date of which was fixed as May 8 , 1907 , by proclamation dated October 12 , 1906. The Indian Mining Law was supplemented by Ordinance No. 38 , of 1930 , which was passed by the Volksraad on March 18 , 1930 , to become effective on October 1 , 1930 ( superseding an earlier ordinance entitled " Government Gazette , " 1906 , No. 434) . An important law with respect to American petroleum rights , Statute No. 23 , passed February 9 , 1928 , approving contracts between the Indian Government and the Netherland subsidiary of a large American oil company , is in the nature of a private law or of an enabling act ( see section of this paper entitled " Rights of Foreigners" ) . Statute 1930 , No. 348 , effective October 1 , 1930 , sets forth in minute detail conditions under which prospecting and mining permits may be granted. Statute 1930 , No. 341 , effective October 1 , 1930 , embodies the police regulations of the mining industry.

Jun 1, 1931

By John C. Hartley

Large areas of the anthracite beds in the Wilkes-Barre, Pa., region have been first-mined in such a manner that over half of the original coal has been left underground as pillars to support the overburden. To recover the maximum amount of this remaining coal, improved devices to support the roof while pillars are being extracted are needed. Also needed are suitable backfilling systems that will stabilize the strata during the mining and effectively limit the inevitable subsidence after pillars are removed. Accordingly, the Federal Bureau of Mines furnished 400 yielding steel props that had been purchased abroad, where this type of prop had been used successfully. The cooperating company arranged for concurrent tests with a mechanical stower designed and built by an American manufacturer. In the area in which the experiments were conducted, pillar removal, using conventional timbering, was most difficult because the roof fractured badly, the installation of timbers consumed a substantial part of the work effort, and some coal nearly always was lost. With the application of the yielding props, the time needed for securing the roof was reduced 33.9 percent; production per man-shift was in¬creased over 33 percent; coal recovery was improved more than 9 percent; and the convergence between roof and floor, during mining and backfilling, amounted to as much as 8.03 inches without any break in the roof. However, in September 1953 some roof rock fell in pillar 10 owing to insufficient props in a small area where the ends of three top holes drilled in the coal face extended up into the roof rock.

Jan 1, 1956

By Jack W. Carlson

Considering the magnitude of today's public concern with critical mineral and fuel materials, regarding both their midterm and long term availability, the Nation is fortunate to have in place and operating the coordinated data systems of the Geological Survey and the Bureau of Mines. Under the supervision and policy direction of the Assistant Secretary--Energy and Minerals, these Department of the Interior agencies have long been responsible for important mineral activities in the Federal Government. Aside from their highly respected mineral industry publications such as the monthly Mineral Industry Surveys, annual Commodity Data Summaries and topical Professional Papers and Reports of Investigation, the Bureau of Mines and Geological Survey data bases and expertise have been readily available for use in emergency situations. Policymakers and decisionmakers in government have placed major reliance upon this ready mineral data and analytical capability in World War II, the Korean War, the recent price control era, and the Arab oil embargo.

Jan 1, 1975

By Philip J. H. Ball

The new application and development of grout jacking processes has combined, over the last decade in particular, to provide a method by which the effects of new underground construction on superficial structures can be controlled to acceptable levels. This paper sets out the basic principles, processes and limitations of compensation grouting. It describes key elements of the philosophy and design and details the control systems required to perform satisfactorily. To illustrate the application, a case history is described for the construction of a shaft and tunnel within and beneath the prestigious structure of Harrods in London.

Jan 1, 2000

By M. R. Tek, K. H. Coats, D. L. Katz

The performance of a gas reservoir su,bject to water drive is often affected by interference due to gas procluction or injection in neighboring reservoirs adjacent to a common aquifer. Field data available on production-pressure behavior of several reservoirs indicate that prediction of reservoir performence must include the effects due to mutual interference. A method developed to predict the performance of two or more interfering gas reservoirs, subject to specified production-iniection .rchedule.s, is presented. The method involves the comhinatiorz of the theory of unsteady-state water movernent with appropriate meterial balance consideration.s. The procedure which extends M. Mortada's treatment for interfering oil reservoirs makes use of his dimen-.sionless pressure drop quantities. prevented graphically in the literature. In order to evaluale the predictive accuracy and practical field applicability of the theory, the method has been applied to analyze the performance of two actual gas reservoirs in mutual interference. The calculations were performed on an IBA4 704 computer. The predicted performances were alro calcltlated with the interference effects ignored. The results show that considerably better agreement between calculated and observed behavior ic. obtained when the interference effects are included. INTRODUCTION Fluid communication between any number of oil or gas reservoirs adjacent to a common aquifer results in mutual interference effects on their production-pressure behavior. The theory, application and interpretation of pressure build-up behavior of oil wells, drawdown tests on oil or gas-producing formations and behavior of several storage reservoirs indicate ample experimental evidence of mutual interference. A method developed to compute the behavior of interfering oil reservoirs was published several years ago by Mortada.4 Studies conducted during the recent years on underground storage of natural gas clearly indicated the need for extending Mortada's work to the case of interfering gas reservoirs. The adoption of appropriate material balance equations in conjunction with the unsteady-state pressure interference theory yields pressure-explicit equations. Their solution, their application to a specific case history and an over-all evaluation of the developed method through the comparison of predicted and observed field performances were the main objectives of this study. DEVELOPMENT OF MATHEMATICAL RELATIONS The diffusivity Eq. 1 governs planar, radial, unsteady-state compressible liquid flow through a porous medium. ?p/?r2+1/r ?p/?r=µFc/k ?p/?t (1) The 1iterature1,2,3 contains derivations and solutions of

By J. R. Hamke

THE WILLISTON basin is the largest known sedimentary basin on the North. American continent. Two-thirds of this large basin lies within the United States in Montana, North Dakota, and South Dakota. Less than 10 years after the first commercial oil discovery in North Dakota in 1951, the petroleum became one of the largest industries in the three-state area. Crude petroleum is now the most valuable mineral resource in the area. In 1960, the basin produced 39 million barrels of worth $100 million at the wellhead. Most of the 137 oil pools covered to date are in Paleozoic carbonates at depths ranging from 3,000 to 13,000 feet. The major producing fields, centered on the Cedar Creek anticline in Montana and the Nesson anticline in North Dakota, produce from depths below 6,000 feet. This report presents descriptions of all phases of the Williston basin petroleum industry, including leasing, exploration, geology, drilling, production, transportation, and refining. Engineering, physical, and production data, maps, and crude petroleum analyses for 137 separate oil pools are included.

Jan 1, 1966

By Colin Rawlings, Simon Pepper, Maria Karakitsiou, John Mathews, Peter Townsend, Russell Bowler, David Keeble, Christopher Darton, Scott Sadler

National Grid needs to maintain a connection between two existing electricity sub-stations (Beddington & Rowdown) in the Croydon (south London) area, and allow the replacement of two 275 kV cable circuits that are buried under roads. This is to be achieved using a single 400 kV cable circuit within a 10 km (6.25 mile) long, 3 m (9.8 ft) diameter high voltage cable tunnel which is being driven through water bearing Chalk, at depths ranging from 5 m (15 ft) to 80 m (262 ft), with four access shafts(12.5 m (41 ft) in diameter) ranging in depth from 10 m (31 ft) to 40 m (131 ft). The Chalk in this area acts as a source of public drinking water supply (PWS) and is protected by areas designated Groundwater Source Protection Zones. To minimise the groundwater risk the design and construction of the cable tunnel and shafts has paid particular attention to the construction materials used, including testing of these construction materials prior to use, developing construction methods (including the design of the Earth Pressure Balance TBM) and maintaining a groundwater monitoring & testing programme prior to and during construction to ensure the integrity of the Chalk aquifer is maintained as a drinking water source. This paper describes the tunnel &shaft design and construction in relation to these particular groundwater environmental issues which set new precedents for tunnel assessment, design and construction requirements in the United Kingdom.

Jan 1, 2007

Experimental investigations were made into the decoppering of lead, tin, and bismuth using a technique which approximates on the small scale to industrial practice.Decoppering lead with sulphur alone in the absence of tin and silver did not proceed to low copper values. With a minimum of 0·02 per cent Ag or 0·10 per cent Sn, lead was decoppered to less than 0·01 per cent Cuby stirring with 0·2 per cent S over 10 min. Decoppering of tin or bismuth proceeded rapidly to very low levels in the absence of any "catalytic" impurities, at any rate in excess of those concentrations normally encountered in commercially pure tin or bismuth.

Jan 1, 1971

By Karsten Beckhaus

"Abstract Tremie concrete for special geotechnical works needs special properties, especially during the casting process. Today’s execution standards for bored piles and diaphragm walls, EN 1536 and EN 1538, as well as the draft version of concrete standard EN 206, all comprise regulations for deep foundation concrete which have not been changed for decades. Considering the recent development in concrete technology at the same time and its actual state-of-the-art, it is essential to develop new normative specifications and specification requirements.GeneralTo allow the required integrity and quality after placing and hardening, concrete for structural elements like bored piles or diaphragm walls, used as foundations of high-rise buildings or as retaining structures for large and deep building pits, must have adequate workability and stability.In addition to requirements on mechanical properties and on durability, both of which have increased within the last decades, concrete must be suitable for being cast in deep or extremely deep excavations, see figure 1. Today’s specialist foundation engineering machinery makes it possible to drill or cut down to in excess of100 m depth. Concrete technology has developed and allows the use of high performance concrete for deep foundations. But is this capability represented by actual regulations?It has become very common for the industry to supply or use concrete with low water cement ratios, nevertheless highly flowable and set-retarded for several hours if needed. Very low water cement ratios allow design strength of 60 MPa or higher (Larisch, 2011), and a very low porosity which is required for a long service life in aggressive conditions, e.g. by chlorides.To achieve best performance, it is obvious that the concrete must completely fill the excavation and fully embed the reinforcement. As vibration of deep foundation concrete is (usually) not allowed and was anyway inefficient, deep foundation concrete must be designed to self-compact under hydrostatic pressure. Generally, it must be considered that after placement the concrete’s quality cannot be influenced anymore. Therefore, both the pouring procedure and the concrete quality must be adequate."

Jan 1, 2014

By Kenneth G. Skinner

The rapid growth of the metallurgical, chemical, and allied industries on the Pacific coast just prior to and during the war caused a sudden increase in the demand for refractories, which was the immediate cause of a revival in interest in refractory clays available on the Pacific coast, particularly in the Pacific Northwest. Population increases and shortage of shipping facilities caused an increase in the amount of various ceramic materials and products used and produced on the Pacific coast, with accompanying demand for information regarding sources of clay. In an effort to supply part of this information, the Bureau of Mines, in cooperation with the College of Mines, University of Washington, started a program in 1944 to test the refractory and other properties of clays from seven Pacific Northwest deposits that had been drilled and sampled as part of the Bureau of Mines alumina from clay investigation. Figure 1 shows the location of these deposits.

Jan 1, 1949

By J. Kretschmann

Around the world, mining has been done for thousands of years for the benefit of humankind. The winning process in mining operations ends with the depletion of the deposit or its closure if the operation becomes economically unprofitable. After that, a period of post-mining follows which may last for a very long time and which is generally regarded as a period of hazards, risk and high cost. In the USA alone, approximately 500,000 abandoned mines do exist; worldwide, there are millions. In Germany, too, we have had to deal with abandoned mines for a considerable period of time now.

Jan 1, 2012

By Thomas Donnelly

Introduction THE Province of San Cristobal is situated on the south side of the island of Santo Domingo about 25 miles west of Santo Domingo city, the capital of the republic. The copper mineralization is found about 1.-CAMP BUCARO. THE TOP OF THE RIDGE IN THE BACKGROUND MARKS THE CONTACT OF THE LIMESTONE AND TUFFS. S miles north of the town of San Cristobal, in the section known as Bucaro Hill; in San Francisco Hill; on the Nigua River; and on the Jaina (Liver. The district is reached by automobile from Santo Domingo city over an excellent road for 25 miles to San Cristobal, and then, by horse-back 6 or 8 miles up the Nigua River to what is locally known as "Camp

Jan 8, 1915

Australian rutile and zircon concentrates are refined raw materials and not manufactured products. The composition and properties of the grains are therefore fixed by nature. Specifications and assay certificates should take this into account by eliminating unnecessary provisions which only increase the time and cost of analysis.INTRODUCTIONThe raw material from which Australian rutile and zircon concentrates are isolated is beach sand on the coast of New South Wales and Southern Queensland. The principal current operations are in an area between Sydney and Brisbane.The sands consist principally of quartz particles, but they contain from 1 per cent to 50 per cent of a mixture of heavy minerals, including zircon, rutile, ilmenite, monazite, leucoxenic grains, chrome spinel, chromite, garnets, corundum, topaz, brown spinel, olivine, epidote, clinozoisite, tourmaline, magnetite, hematite, and cassiterite. The major components are zircon (25 to 60 per cent), rutile (25 to 50 per cent), and ilmenite (5 to 50 per cent).The so-called leucoxenic grains are not a definite mineral species but an alteration product of which the major components are titanium oxides and silica in varying proportions.Primary concentration is by gravity, using spirals or various forms of pinched sluice (Pullar, 1962), the resulting concentrates being redressed on wet tables. During these processes, some of the lighter heavy minerals including leucoxene and impure rutile, which tend to degrade the final rutile and zircon concentrates, are eliminated.The separation of heavy minerals from each other is...

Jan 1, 1963

By Patrick A. Hamilton

This Bureau of Mines report delineates the coal reserve base of anthracite, bituminous and subbituminous coals, and lignite, by mining method and sulfur content, for coal-bearing States west of the Mississippi River. The parameters used to establish the reserve base definition are the result of a joint agreement by the Federal Bureau of Mines and the U.S. Geological Survey. The reserve base of low-sulfur coal, =10 percent sulfur, is 167,324.5 million tons; medium-sulfur coal, 1.1-3.0 percent sulfur, is 37,531.5 million tons; and high-sulfur coal, >3.0 percent sulfur, is 11,244.1 million tons. The reserve base of coal with an unknown sulfur level is 18,323.0 million tons. The percentages of deep and strippable coal are 56 percent and 44 percent, respectively. The basis for reserve base estimates and analytical data for this report was the Fuels Availability System, a Bureau of Mines data bank containing numerous data tin fossil fuels. Information contained in the system was obtained from publications of the Bureau of Mines, U.S. Geological Survey, State agencies, private publications, and company data.

Jan 1, 1975

By M. M. K. McCrank

"PRACTICAL SAMPLING TECHNIQUESIt is important to achieve reliability when sampling heterogeneous materials where there is a difference in composition, and non random distribution of the constituent particles. Throughout the design, construction and installation of sampling systems it must be borne in mind that the sampling point must be capable of:-allowing each particle in the stream an equal opportunity to be sampled.-accepting and collecting as large a volume or mass of material as necessary to satisfy the requirements of particle counting statistics.-establishing a sampling plan so that the sample is representative of the whole to a defined standard of accuracy.Design ConsiderationsFactors that may influence the design of the sample point include:-the mass, or volume flow rate of the material being sampled-the size and shape of the material or flowing stream-the physical condition of the material being sampled (i.e. temperature, wetness, size consist, density).-the chemical composition of the material being sampled -the location of the sample point and the space available for installation, extraction, reduction where necessary, secondary sampling, and return of the sample rejects downstream.-whether the process to be sampled is in an existing plant or one yet to be designed and built.-ease of access for servicing and maintaining the equipment.-whether the sampled material must be collected continuously or intermittently.-whether an existing sampling method is likely to be adequate or whether a new technique has to be developed."

Jan 1, 1989

A President, soon after he is appointed, sees looming ahead of him the Presidential Address; and in something approaching despair wonders what he can possibly talk about which might hold the interest of his audience. After various casts about, it occurred to me that perhaps prospecting, and more particularly prospecting in Australia, might provide a subject. This is because, 'in the first place, 'prospecting is passing from the stage of chance surface discovery to that of systematic search applying scientific methods to theproblems involved, and in the second, it is the section of the industry with which I have been concerned through much of my: working life. As it makes an address of this sort more interesting if it includes specific reference to actual experience, I hope you will bear with me in such references to actual prospecting as I may use to illustrate the argument. Prospecting has always carried the glamour of sudden wealth. The picture of the prospector engaged, perhaps for years, in fruitless search suddenly coming on riches beyondhis hopes is, deeply etched in the Australian imagination. In few other places has the fervour of prospecting run higher than it did in Victoria in the generation beginning little more than a century ago following the discovery of gold.People arrived from overseas in great numbers. Most of them proceeded to: the goldfields. They moved in thousands from new find to new find. In 'so doing' they determined much of the course of the State's development. The experience of prospectors led them to formulate all sorts of theories little impeded by awkward facts, to account for the apparently unpredictable occurrence of gold.The ideas which men followed, occasionally to success, and which they were prepared to back with all they had were strange and, various, many stories are told of them.

Jan 1, 1959