Search Documents

By William J. Bronkala

One of the oldest tools used in mineral concentrating is the magnetic separator. Virtually every mineral handling system has need for some type of magnetic equipment in two types of basic usage. 1. Equipment protection through tramp iron removal. 2. Mineral concentration based on magnetic properties of the minerals contained in the ore.

Jan 1, 1969

By J. D. Warne

The ferberite district of Boulder County, Colo., has been an important producer of tungsten since 1900. During World War I, high prices for tungston concontrates resulted in a brief period of intense activity, and the production in 1917 was 2,707 tons of 60 percent W03 concentrates. Production declined thereafter, and in 19.2 the tungsten produced in Boulder County represented about 4 percent of the Nation's output, being exceeded only by the scheelite production in California, Nevada, and Idaho. Boulder County has boon an important source: of tungsten in the Korean emergency; the present report does not describe this recent activity, as it will be covered by a future publication. Tungsten occurs in small ore shoots of narrow and irregular veins. Most of the ore shoots have been found outcropping on the surface. Core drilling; has been used by the larger operators to explore for new veins and to locate extensions of known veins.

Jan 1, 1953

By F. A. Rutledge, B. S. Webber, J. M. Moss

"INTRODUCTION The United States, with its vast resources of relatively low-grade zinc been the world's leading producer of zinc -metal for many years. The expanded zinc production during the period, 1939-44, inclusive, was induced by favorable premium prices and has depleted the known ore reserves in the United States. The 1943-44 rate of zinc production cannot long be maintained in the United States, especially if premium prices are removed. Domestic zinc reserves, have been depleted to such an extent that it is doubtful if our mines will again be able to completely and continually fulfill the needs of this country.The Bureau of Mines, anticipating a postwar consumer demand for 550,000 to 750,000 tons of slab zinc and an additional 100,000 tons for use in paints and chemicals, sent two engineers to Sedanka Island in July 1945 to investi¬gate the deposits near Biorka Harbor.ACKNOWLEDGMENTIn its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion the Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches are under the supervision of Dr. R. S. Dean, assistant director."

Nov 1, 1946

By V. R. Degner

En las últimas décadas la declinación en los contenidos metálicos de los yacimientos mineros se ha constituido en un aporte para el desarrollo progresivo de máquinas de flotación de gran tamaño. En este sentido, las máquinas de flotación de las décadas del 50 y 60 fueron reemplazadas por máquinas de mayor capacidad, potencia y simplicidad en los controles del proceso, adquiriendo ventajas económicas y operativas que pueden ser aplicadas a los diseños de plantas de gran tonelaje en el futuro. Por ello, el objetivo del texto es revisar los procedimientos seguidos en el desarrollo sistemático de las celdas de 1000 pies3 de capacidad y la evaluación de su performance en el beneficio de minerales metálicos.

Oct 14, 1980

By Richard E. Ellwanger

Methods of utilizing flocculants as settling and filter aids for mineral processing slurries are reviewed. Broad chemical classifications and techniques for proper dilution, multiple addition, and combination treatments are discussed. A variety of custom built and commercially available systems for make up and delivery of flocculants to the application points are in use through- out the mining industry. Those concepts which, in the author's opinion, are particularly important to the successful make up and use of flocculants are presented in relationship to the available make up and feed systems. Actual industrial applications are included in the presentation.

Jan 1, 1980

By I M. Platten, Y Xie, B W. Cuffley, S C. Dominy

"Geometallurgical programs require the collection of representative samples for geochemical, mineralogical and metallurgical test work. Such protocols must be designed to suit the style of orebody in question. The distribution, proportion and size of gold particles have a direct impact on the effectiveness of sampling and test work protocols, and the gold recovery processes employed. Characterisation studies focusing on ore mineralogy, and gold particle deportment, size and distribution are required. High resolution X-ray computed tomography provides a non-destructive method for analysing the 3D nature of gold in rock samples. It can be used to calculate the modal abundance, particle size and distribution of gold in the sample volume. This paper presents a case study of the imaging of in situ gold particles in a high-grade gold ore. The Nick O’Time reef system comprises laminated quartz veins, which locally bear extreme grades of up to 100 oz/t gold. The mineralisation has previously been characterised from both a mineralogical and metallurgical perspective. Eight visible gold-bearing vein samples were scanned using X-ray microtomography. Microtomographic data were integrated with previous mineralogical and metallurgical test work outputs.CITATION:Dominy, S C, Platten, I M, Xie, Y, Cuffley, B W and O’Connor, L, 2016. Characterisation of Gold Ore from the Nick O’Time Shoot (Tarnagulla, Australia) Using High Resolution X-ray Computed Tomography, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 241–254 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By Robert D. Coale

This paper will describe the copper concentrate slurry pipeline and pumping system between the concentrator and the port at Bougainville Copper Ltd. The operations of Bougainville Copper Ltd. are located on the island of Bougainville in the South Pacific. Geographically, it is the northernmost island of the Solomon Group but, politically, it is part of Papua New Guinea. Papua New Guinea is a United Nations Trust territory administered by Australia, having recently been given self-government, with independence scheduled for December 1974. (Fig. 1). The island is approximately 130 miles long by 30 miles wide, with the Crown Prince mountain range forming a spine along its length. The mountains in place are over 8,000 feet high with the mine located on the western flank at an elevation of 2,200 feet. Exploration on Bougainville for copper by Conzinc Riotinto of Australia (CRA) began in 1963 and by 1968, through geophysical, geochemical and diamond drilling methods, an orebody containing nearly one billion tons of ore grading approximately 0.48% Cu. and sane gold had been outlined. Bougainville Copper Ltd., the company operating the mine, is 53.6% wined by CRA, 20% mined by the government of Papua New Guinea with the public Folding the remainder of the shares. The first copper concentrate was produced in early 1972, with production for the first full year, 1973 being:

Jan 1, 1974

By AIME AIME

THE list of deaths reported during the year 1904 comprises the following names (the figures in parentheses indicate the year in which the persons named were elected to membership). Honorary Members.-Sir Lowthian Bell, Dr. Thomas M. Drown. Members and Associates.-Jacob Neff Barr (1884), John Walter Best (1899), A. Poyntz Blandy (1903), A. Cass Canfield (1876), William E. Carroll (1901), William E. C. Coxe (1874), Russell W. Davenport (1877), Isidor Davidov (1893), Louis M. Davis (1884), Edward Doerr (1897), Edward M. Ferguson (1878), C. Le Neve Foster (1893), Geo. Clinton Gardner (1878), Wm. J. Harris (1871), Richard P. Heckscher (1893), H. D. Hoskold (1.894), Wm. S. Hungerford (1882), Edwd. K. Landis, (1882), August Lengemann (1902), Wm. M. Lippitt (1900), Henry McCalley (1888), Robert J. McCartney (1897), Arthur McClellan (1871), Arthur S. Mahony (1888), Philip W. Moen (1888), Henry G. Morse (1881), Charles Parkin (1875), Clarence V. Page (1900), Rubens P. Patterson (1886), Henry Paul (1889), W. H. Pettee (1871), James B. Randol (1879), Irving H. Sevier (1904), Win. J. Sims (1902), John H. Slavens (1901), Chas. B. Squier (1886), Chas. W. Stickney (1891), Homer H. Swaney (1903), Walter B. Wilson (1892), Whittaker Wright, The following paragraphs, constituting the concluding portion of the Annual Report of the Council for 1904, have been withheld from publication until now, in order to make them as accurate and complete as possible. Jacob Neff Barr, a mechanical engineer of note, died on May 5, 1904. Being especially interested in railroad work, he invented the Barr contracting-chill process of casting car-wheels,

Jul 1, 1905

By Bedrand L. Johnson

THE phosphate-rock industry is built upon natural deposits of rocks and minerals in which the element phosphorus is present as a phoshate. The term ?phosphate rock? is a general one, applied to certain rocks of different degrees of consolidation and of diverese origin, charater and occurrence, composed of intimate mixtures of several phosphate minerals, largely submicrocrystalline, usually calcium phosphates, in commerical quantities, with various impurities. This term includes phosphatized limestones, sandstone, shales, and igneous rocks; nodular phosphates ; residual weathered phosphatic limestones ; vein phosphates ; and phosphatic sediments, both consolidated and unconsolidated.

Jan 1, 1944

By A. W. Gauger

DESPITE many handicaps and in the face of many discouragements anthracite and bituminous coal producers continue to supply the needs of the nation now vastly multiplied by the demands of the greatest war of all time, total output being about 620,000,000 tons of bituminous and 64,445,000 of anthracite. The progress made by this industry during the national emergency reflects more credit on all connected therewith than will ever be given. Not only has the industry been called upon to produce more coal than ever before but it has also sent representatives to England to study and advise on methods for increasing production there, and has co-operated with other Allied Nations by welcoming engineers sent to this country to study American practice. One noteworthy development has been the growth of strip mining in the

Jan 1, 1945

By L. F. Reinartz

ANOTHER year has rolled by. We are twelve months further away from the start of the depression and. therefore that much nearer to recovery. The accumulated needs and wants 'of our lame, virile population are ready to burst their bonds as soon as confidence returns and credit is stabilized. The steel industry has been harassed by uncertainty of the Government's attitude toward organized labor's de¬mands, and irregularity in volume of production. Steel labor, if left to its own devices, would in most instances, march shoulder to shoulder with the management of steel plants in their effort to pull the industry nut of the ?red.? Cooperation between management and men has improved considerably during; the year.

Jan 1, 1935

By Thomas Novak, Sampurna Arya, Joseph Sottile

Dust generation and its dispersion in a longwall mine pose significant health and safety issues. The concern is prominent at both the working face, where coal excavation exposes workers to high dust concentrations, and also in the return, where float dust accumulates. To address this issue, researchers at theUniversity of Kentucky designed and fabricated a flooded-bed dust scrubber integrated into a full-scale physical model of a longwall shearer. This mock-up was installed in the longwall test gallery at the Pittsburgh Research Laboratory (PRL) of the National Institute for Occupational Safety and Health (NIOSH). A full-factorial experiment was designed to measure the effectiveness of the scrubber on dust capture. Test results indicated dust reduction of up to 57% in the return airways. This paper presents the development of a computational fluid dynamics (CFD) model and its validation by comparing the simulation results against the experimental results. The CFD simulations show good agreement with experimental results with differences between + 6.9 and − 9.7%. The validated CFD model was used further to predict the scrubber performance under additional operating conditions, resulting in a dust reduction of up to 66.5%. With this level of success, the scrubber concept can be a game changer for the mining industry, and it can be utilized to improve health and safety in longwall mines.

May 26, 2020

By R. E. Ray

As coal reserves at shallow depths continue to be exhausted, a number of U.S. coal mining companies are beginning to develop coal seams previously thought to be coo deep to mine economically. Because of increased cover load, mines operating in deeper seams face unique ground control problems. In addition, the volume of methane gas contained in coal beds increases with depth, and ventilation requirements are much more stringent for deep underground coal mines than for shallower mines. When the longwall mining method is used at great depths, ventilation, ground control, and operational considerations must all be addressed in the design of longwall panels. This paper examines the influence of these factors, particularly ventilation and operational considerations, upon the feasibility of two, three, and four-entry longwall development panels in Jim Walter Resources' four deep mines.

Jan 1, 1986

By Ana Chiquini, Clayton V. Deutsch

The most common approach used in the mining industry for mineral resources modeling is to estimate the grades using ordinary kriging and report the recoverable resources based on this deterministic estimated model. Mineral resources calculated with kriging are a smooth representation of the actual distribution of grades and do not provide an assessment of uncertainty. Unlike kriging, simulation reproduces the variability of the grades in the mineral deposit and provides an assessment of uncertainty. Reporting mineral resources directly on high-resolution simulation results would assume perfect knowledge of the grade at the time of mining and selectivity at the scale of the data. There will always be uncertainty left at the time of mining, so assuming perfect knowledge of the grade in the future is incorrect. There are two concerns when geostatistical simulation is used for resources modeling: the information and the mining selectivity effects. A new framework for resource estimation is proposed with two separate modules to address those concerns. The information effect is accounted for by anticipating the additional production data that will be available at the time mining to guide the destination for the mined material. The mining selectivity effect is addressed by mimicking the grade control procedure to get mineable dig limits at a chosen selectivity, represented by a minimum mineable unit size. In addition to a prediction of recoverable resources that will be closer to the material mined in the future, the framework proposed provides an assessment of local and global uncertainty for risk management.

May 26, 2020

By VlNTON H. CLARKE

Diamond-drill blasthole sloping has now been used for a long enough time to permit us to discuss fairly its problems from the ore-breaking angle and to attempt to peer into its future. To do this we have gathered information from many properties through questionnaires. The operators have indicated fairly well in their answers what they think of the method. The many variations of methods have by now been fairly well developed, and performance rates and. mining costs are well established at each property. All this can be laid down on paper with fair completeness. Now. knowing all this, what will the future of the method be? To attempt to look into the future of a mining method immediately brings to light many problems and variables. For instance: why were diamond drills used in the first place? What has the cost trend been? In what type of deposit has the method proved most advantageous? What will the future cost of diamonds be? What are the possible substitutes?

Jan 1, 1949

By H. O. Hofman

(Canal Zone Meeting, November, 1910.) I. INTRODUCTION. IN a previous paper,1 The Behavior of Calcium Sulphate at Elevated Temperatures with Some Fluxes, we published the results of our investigation, into the behavior of calcium sul-phate in air; that, is, under oxidizing conditions. The results as a whole hold good for a neutral atmosphere, or one which has no chemical effect upon calcium sulphate. The present paper deals with the behavior of calcium sulphate under reducing conditions, the reducing-agents employed being carbon monoxide and carbon, and the changes the calcium sulphide formed undergoes when it is subjected to an oxidizing-roast. Technical literature deals very sparingly with the subject. The information furnished by the recent leading chemical manuals is general. Thus Dammer,2 Moissan,3 and Abbegg,4 quote Berthier as having reduced, in 1823, calcium sulphate with carbon, and Stammer as having done the same in 1851 with carbon monoxide; Gmelin Kraut 5 add Leplay and Laurent (1848) as third investigators. Metallurgical authorities confine their statements to the known fact of reduction by carbon. II. PREPARATION OF RAW MATERIALS. 1. Calcium Sulphate.-This salt was prepared in the same manner as described in our previous paper,6 and was found to be chemically pure. * Professor of Metallurgy, Massachusetts Institute of Technology. + Metallurgical Instructor, Imperial Technological Institute. 1 Trans, xxxix., 628 to 653 (1909). 2 Handbuch der anorganischen. Chemie, vol. ii., part 2, p. 309 (1894). 3 Traité de Chimic Minérale, 1904, vol. iii., p. 543. 4 Handbuch der anorganischen Chemie, vol. ii., part ii., p. 116 (1905). 5 Handbuch der anorganischen Chemie, vol. ii., part 2, p. 233 (1909). 6 Trans., xxxix., 630 (1909).

Nov 1, 1910

By Dinner Paredes

El presente trabajo técnico, denominado “Impulsando la competitividad minera en el Perú: La economía circular y los incentivos tributarios como elementos claves para el desarrollo de una minería sostenible”, tiene como propósito primordial analizar y resaltar la importancia que tienen los principios de la economía circular y los incentivos tributarios para promover un sector minero competitivo y sostenible en el Perú.

Sep 29, 2023

By George H. Holmes

This paper , which describes mining methods and milling and manufacturing operations at the gypsum property of the Blue Diamond Corp. , is one of a series on mining methods and practices being prepared by the Mining Division of the Bureau of Mines . The property comprises about 4,000 acres and is in secs . 30 , 31 , 32 , and 33 , T. 21 S. , R. 59 E. , and secs . 5 , 6, 7 , 8 , and 9 , T. 22 S. , R. 59 E. , M. D. B. and M. , Clark County , Nev . , approximately 23 miles by paved highway southwest of Las Vegas , Nev . ( fig . 1 ) . This circular summarizes the history of company operations , describes physical features , labor and living conditions , and the geology . The method of exploration is outlined , and the section on mining methods contains descriptions of open - pit and underground systems , including loading and transportation methods . The crushing plant and tramway are described , as well as plaster-mill and board -plant practices . The boiler plant and organization are described , and wage scales are contained in the concluding section of the circular .

Mar 1, 1950

By C Laming, P M. Hetherington, F A. Pym, M P. Murphy, K E. Crook

Reconciliation is a powerful tool used by mining operations to compare the mass and grade of ore produced with what was estimated before mining. The primary objective of reconciliation is to verify that the estimated planned metal production is achieved during processing, allowing issues to be identified for which adjustments can be made throughout the mining value chain to improve recovery and maximise efficiency. Traditionally, the mine plan is based on estimated mine grades using sampled exploration drill hole or blasthole grades. Reconciliation discrepancies between the mine plan and mill are common due to such factors as insufficient or non-representative sampling, poorly conceived models, or unrecognised blast movement. MineSense Technologies Limited® (MTL) has developed an X-ray fluorescence (XRF) sensor-based ore classification system that is installed on mining equipment to provide real-time grade estimates of run-of-mine material at bucket, truck, or belt-scale. Bucket level grade estimates provide insights into grade variations at the mine face that were never before available. This data set eliminates some of the leading causes of reconciliation discrepancies and enables tracking of tonnages and grades from the mine face to the processing plant at bucket resolution with confidence. Bucket-by-bucket grades at the mine face enable dynamic optimisation of the mine plan to stabilise the mill feed grade through blending of mine and stockpile loads. Beyond stabilising feed grade, Mine to Mill reconciliation combined with the full XRF spectrum response can generate proxy relationships to ore characteristics like hardness and recovery. These properties can then be predicted at the mine face, enabling further optimisation of the downstream mill feed, not only for grade, but also for power and water consumption, reagent addition, and recovery. This paper presents the benefits of MTL technology for grade reconciliation and mill performance optimisation at a Cu Mine in BC (Canada).

Mar 22, 2022

By Dodd SF

Valuation of mining companies and their underlying assets prepared by brokers' analysts are, by necessity, approximations. The reliability of the valuations is entirely proportional to the quality of available data, the reliability of forecasts and the nature of underlying commodity price assumptions. The latter is perhaps the greatest single cause of gross variations in company and asset earnings estimates and- valuations. Assumptions are often necessary regarding commodity price achievement based on commodity hedge positions. Public disclosure from listed companies provides a sound base from which to project earnings, cashflows and balance sheets. The uncommon disclosure of projected production and cost schedules often reduces the reliability of future estimates. The application of reserve and resource estimates is contentious with practitioners applying differing weightings to importance of resources in estimating mine lives (and therefore cashflow streams). Valuation methods applied in equity markets usually focus on relative value and the identification of pricing anomalies. The commonest ""rules of thumb"" applied in the valuation of mining companies (and therefore their underlying assets) is with the use of year specific price/earnings (P/E) and price/cashflow (P/CF) ratios, with low multiples suggesting undervalued assets, high multiples overvalued situations (but these rules can often be clouded by market expectations of underlying commodity price movements). Another simply applied valuation tool is to examine the examine the value placed on reserves and resources by the market. Inexpensive gold in the ground (expressed as $ of market capitalisation per ounce of reserves or resources) might indicate a buying opportunity, but the market does discount the value of gold in the ground prior to mine development and where development risk is perceived.

Jan 1, 1994