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By Charles T. Ford

Limestone neutralization of acid mine drainage has been proposed and examined as a method of treatment. However, limestones differ greatly in composition and structure. The reactivity of 14 selected limestones was studied, both by chemical and physical properties and by relative effectiveness in neutralizing synthetic and actual mine waters, and several guidelines for the choice of limestones are given. The particle size should be at least as small as 74 microns and preferably smaller. The most effective limestones are most nearly pure calcium carbonate. Stones which have a relatively low calcium con- tent but which contain calcite and have a large surface area are also effective neutralizers. Magnesite and dolomitic limestones are much less reactive. Disadvantages in using even the most reactive lime- stones for neutralization are indicated.

Jan 1, 1974

By R. H. Storch

The work described in this report was part of a Bureau of Mines program to appraise the titanium-mineral resources of Idaho. Part of the program included churn drilling of alluvial deposits that previous preliminary testing, primarily for rare minerals, had indicated to be potential sources of titanium minerals. The first spot churn drilling began in the Deadwood placer area, Valley County, Idaho, in July 1956 to determine both the amount and grade of the ilmenite, FeTi03. Ten holes, ranging in depth from 6 to 40 feet and aggregating 251 feet, were drilled; 54 samples were taken. The samples were sent to the Spokane field laboratory for concentration and visual estimation of the amounts of the more common minerals in the heavy sand concentrates. For specific determinations samples from each drill hole were composited and shipped to the Bureau of Mines laboratory in Albany, Oreg., where petrographic, quantitative X-ray spectrographic, and chemical analyses were made.

Jan 1, 1958

By A. G. Roach

HISTORY AND LOCATION SEAL HARBOR GOLD MINES, LIMITED, was incorporated in January, 1934, to take over 116 acres of mining lands in the Stormont gold district, Guysboro county, Nova Scotia. The nearby ten-stamp Mulgrave mill was also purchased, and since that time 974 acres of adjoining properties have been secured from the Government by direct lease. The property is served by a motor road and is about two miles from the village of Goldboro, situated on the shore of Isaac's harbour. The bulk of ?the supplies are brought in by coastal steamer from Halifax, a distance of about 100 miles, since the nearest railway connections are at Antigonish, some 40 miles distant. EARLYY WORK The Seal Harbor properties include the old Partington and Beaver Hat mines. A small tonnage of ore was mined from each and treated on the properties in stamp mills, which were later torn. down . A survey of old records shows that this ore averaged about $8.00 gold per ton. Development work by the present Company was confined to the 100-foot level until February, 1935, but after that rime the incline shaft was deepened to 425 feet and the 300-foot level was explored east and west of the shaft. Six belts of ore were intersected to the west of the shaft. The ore from these belts was hand sorted and the ore portion was put through the 10-stamp Mulgrave mill to defray operating expenses and to serve as a sample of the deposits. The average recovery per ton from this sorted ore was $6.10. Samples of the ore were sent to the testing laboratories of the Mines Branch, at Ottawa, and of Canadian Industries, Limited, at Toronto. Recommendations from both of these authorities were for removal of the coarse gold by concentration and barrel amalgamation, followed by cyanidation of the residue.

Jan 1, 1937

By Denise Müller, Axel Preusse

"Due to multilateral underground use, mining subsidence is discussed more and more with regard to issues other than mining, such as post-mining topics, storage, or geothermal use. These discussions and the influence of the energy policy is why the situation in Germany is described as a transition from active to abandoned mining. Many PhD theses have been written within the last 20 years—every single one with a different topic but all with the same issue—the effects and challenges of mining subsidence.These challenges start with the research regarding geological and hydrogeological conditions, which is the basis for calculations like the angle of draw or predictions of subsidence due to water table drawdown. Furthermore, the research investigates issues like risk-management and financial planning. One of these issues is post-mining calculations; others include potential hazards of storage or the use of geothermal energy.This paper outlines an overview of German mining and the consequences due to subsidence. It deals with an overview of the circumstances related to hard coal mining, lignite mining, the use of geothermal energy, gas, and opportunities regarding underground storage. Basically, it describes the essential steps of processing mining subsidence, starting with monitoring to forecast and up to safety measures.With a glance back to the applied research of the prior two decades, we compare given forecasts with experiences already gained.Even though mining decreases, ground control does not.INTRODUCTIONAfter the Second World War, an economic recovery started in Germany, during which the mining industry provided an advantage. Areas like the Ruhr District or Saarland were characterized by hard coal mining. In addition, there was lignite mining in the Rhenish mining area and the middle German coal district. In the Lausitz area, there were gravel and sand companies for the construction industry and many other medium-sized mining companies. Especially in the Ruhr District and in Saarland, where large coal fields were built, mining played a major role. The number of mines increased, and the negative effects on the terrain got bigger. While minor open pits or quarries have influences on the landscape only, large open pits and underground mining lead to significant ground movements. This results in a larger importance of mining subsidence engineering. Calculations of subsidence and forecasts have been developed and refined within the last several years. Due to the fact that the mining areas were and still are densely populated, the forecasts are getting more and more precise."

Jan 1, 2018

By I. N. Beall

The present survey indicates 'that the average volatility of motor gasoline now being marketed throughout the country falls well within the limits of Federal Specifications. As would be expected, there is a slight decrease in volatility as compared with the gasoline marketed last wine:., but on the average the gasoline sold today is about the same as that sold last summer. During the past five years the Bureau of Mines has made semi-annual surveys of the gasoline marketed in the United States. To obtain a sample of each gasoline sold is obviously impracticable, but the cities in which samples have been collected have been so chosen as to be representative of the more important marketing territories. It is believed, therefore, that the samples obtained are indicative of the quality of gasoline marketed throughout the country.

Jan 1, 1925

By Pedro C. Carneiro, Luiz G. I. Maciel

"This article presents data of advance and excavation rates in tunnelling works, and how theseactivities interact with the duration and cost of a contract. These key parameters, after analysis andsynthesis, will be used in coming works to ensure the evolution and adaptation of the method created by the Norwegian University of Science and Technology - the NTNU Method - to Brazilianconditions, which will be reflected in the duration and cost of underground drill and blast tunnellingworks."

Jan 1, 2016

By Yuanbo Zhang, Huanpeng Mi, Guanghui Li, Binjun Liang, Zhiwei Peng, Tao Jiang

Ludwigite ore has not yet been utilized on an industrial scale due to its complex mineralogy and fine mineral dissemination. In this study, sodium salts were employed to enhance the separation of iron and boron by reductive roasting-magnetic separation. It was found that the separation of iron and boron as well as the iron grade and recovery were significantly improved b y the addition of Na2SO4 or Na2CO3. Under the reduction temperature of 1050 °C, reduction time of 60 min and magnetic intensity of 0.1T. Compared with the inexistence of sodium salts, the iron grade and recovery of the magnetic concentrate increased from 83.3% and 88.6% to 93.2% and 95.1%, respectively, by adding 6% Na2CO3. The XRD and microstructure analyses indicated that the iron oxides were transformed into metallic iron and the average metallic iron grains were grown to over 40μm which was beneficial for separation of metallic iron from gangue.

Jan 1, 2016

By Pierre De Pasquale, Gilles Jauffret, Ricardo Chavez

"When blasting in quarries or mines, the main source of inconsistent results is directly related to thenon-homogeneous energy distribution through the rock-mass volume. This variation has differentorigins: drilling deviations, geometry differences from one borehole to another (burden, spacing ...),and inherent geological conditions."

Jan 1, 2016

By W. M. Traver

During World War II, the Bureau of Mines investigated a large number of ore deposits in the United States and Alaska in a search for domestic sources of strategic minerals. Deposits chosen for exploration included those expected to contain metals of importance in the successful prosecution of the war. This report describes exploration of a district of known antimony occurrence on Coyote or Antimony Creek near Antimony, Garfield County, Utah. A preliminary report by Paul T. Allsman, Chief of the Bureau's Salt Lake City branch made in August 1941, recommended further investigation, and proposed methods for performing the work. The project, begun in November 1941 and completed in January 1942, included trenching and sampling in four of the most promising parts of the area The Federal Geological Survey cooperated in the work by detailed mapping and assisted in the interpretation of geologic data.

Jan 1, 1949

By C Grobler, M Recklies, G Jiang, I Taylor, M Morgan, G MacDonald, L Smith

The resource estimation of lateritic deposits, such as Aurukun, presents specific issues related to the lateral changes in thickness and elevation of the various horizontal layers (or zones) within the deposit where the x and y dimensions are orders of magnitude greater than the z dimension. The objective was to develop a three-dimensional (3D) block model that retained the vertical and lateral variation inherent in deposits of this type to allow full optimisation of the production plan without prior selection of an economic portion (enriched bauxite layers) of the profile at the resource estimation stage. The Aurukun bauxite deposit is held by Chalco Australia Pty Ltd (Chalco) and forms part of the world-class Weipa bauxite province, Cape York Peninsula, Queensland, Australia. The bauxite is predominantly pisolitic with an upper boehmite-rich zone and lower gibbsite-rich zone. The bauxite consists of both in situ and reworked domains, is overlain by a thin soil horizon and has kaolinite clay as a transitional base. A portable infrared mineral analyser (PIMA) was utilised on site, in addition to elemental assay, on each drill sample to determine the mineralogy, in particular levels of boehmite, gibbsite, kaolinite and reactive silica. As part of the scope of work, a field program was undertaken using large diameter Boart Longyear sonic drilling to acquire detailed density measurements across the deposit to allow compliance with Joint Ore Reserves Committee (JORC) reporting requirements. Interpretation of the stratigraphy was conducted on a hole by hole basis with definition of the zone layering based on stratigraphy, geochemistry and mineralogy. The zone boundaries were then modelled as 3D surfaces and used to constrain a block model. The block model estimation used the ordinary kriging method, with the estimation done in unfolded space and then refolded, therefore maintaining the zones irrespective of thickness or orientation. The unfolding process converts the real-world positions for both blocks and informing samples to a scaled position relative to the roof and floor of each zone. Analysis of the data and variography were also undertaken in unfolded space. The x and y dimensions are unchanged, but the z dimension is a relative position. The effect of the unfolding and limits on number of samples per hole is to æpushÆ the informing sample search sideways but within the stratification, rather than vertically. This honours the strong vertical zonation within the bauxite profile. The JORC Code requires that the stated resource must have æreasonable prospects for economic extractionÆ. This is a qualitative rather than quantitative definition. A number of selection criteria to define a resource roof and floor were developed in consultation with the project engineers and owners to meet these criteria. The vertical selection of material to include in the resource highlights the variation in the development (and destruction) of the bauxite profile from area to area within the deposit.

Jan 1, 2009

By C. F. Cigliana

TO accommodate a large tonnage at high speed from a single level at San Manuel, a very flexible haulage system was designed to give maximum access to stoping areas, minimize delays, and pro- vide for safety. With these requirements as a guide, the haulage was laid out as a simple double loop with one-way traffic of continuous pull. These loops consist of two parallel drifts 100 ft apart, center to center. Haulage drifts are numbered from north to south, the northernmost being the No. 1 drift. This holds true on both the North and South haulage loops. Haulage drifts are connected at 1000-ft intervals with crossovers so that it is possible to bypass any given section that may be inaccessible. Two of these turnouts are double diamonds, one located on the approach to the rotary dumps at the hoisting shafts and the other on the departure from the dumps. The turnout on the approach or North haulage is 835 ft in front of the rotary dump, and the one on the departure, or South haulage, is 1058 ft from the dump. This type of turnout allows trains coming down either haulage drift No. 1 or No. 2 to be routed into either shaft and expedites movement by avoiding delays due to congestion in the dumping area. The double diamond on the return haulage loop facilitates returning empty ore trains to the panels.

Jan 5, 1958

By AIME AIME

Council.* PRESIDENT OF THE COUNCIL. ROBERT W. HUNT CHICAGO, ILL. (Term expires February, 1907.) VICE-PRESIDENTS OF THE COUNCIL. WILLIAM P. BLAKE TUCSON, ARIZ. THOMAS F. COLE DULUTH, MINN. IRVING A. STEARNS WILKES-BARRE, PA. (Term expires February, 1907.) HENRY AL HOWE NEW YORK, N. Y. J. B. GRANT DENVER, COLO. JAMES D. HAGUE NEW YORK, N. Y. (Term expires February, 1909.)

Jan 1, 1907

By Robert Hopler

THIS paper deals specifically with heading-driving as distinguished from the broader term tunnel-driving. A heading is a pilot or path-finder for the main tunnel. Some headings are complete tunnels in themselves; that is, conditions at times warrant driving a heading the full diameter of the proposed tunnel. A tunnel 10 ft. in diameter might be driven to advantage through a single heading, provided the nature of the material admits, but it usually pays to drive rock tunnels of large diameter through the headingand-bench system. Much depends upon the material, as in soft ground tunnels of much larger diameter are driven in a single heading.

Jan 1, 2010

By D. Roy Eccles

A multi-element geochemical response, with contrasts of up to 29 times background, was obtained in soil above the Mountain Lake Diatreme, northwestern Alberta. The overall geochemical signature is indicative of an ultramafic source; geochemical responses contain elevated concentrations of Co, Cr,O, Cu and Ni with the presence of high Ba, Ga, HI, PO,, Rb, Ta, Ti and light rare earth elements suggestive ofa kimberlite or lamproite body. The shape, or morphology, of the enzyme leach-based geochemical signature over the Mountain Lake Diatreme combines moderately strong to strong oxidation halos, or a rabbit's- ear geochemical profile, with a sharply-defined apical geochemical profile. Because some Alberta diatremes discovered to date form positive topographic highs, the resultant geochemical signature may express the soil development profile that forms directly on top of kimberlitic and lamproitic bodies. The enzyme leach technique, which has proven to be a useful tool in base metal, precious metal and petroleum exploration, may have a significant impact on exploration for kimberlite, lamproite and related rocks in Alberta by providing industry with a useful and cost effective tool to probe blind and/or buried anomalies identified by airborne and ground magnetic surveys in areas of glacial overburden.

Jan 1, 2001

By Y. Wang, J. D. Miller, C. L. Lin, Virginia Tech

Conventional flotation machines are typically limited to a particle topsize of 150-200 microns due to inherent constraints created by the pulp and froth phases. To overcome these limitations, a novel fluidized-bed flotation system called the HydroFloatTM Separator has been developed specifically for the purpose of floating coarse particles containing only small amounts of exposed hydrophobic minerals. Over the last decade, this technology has been successfully applied to industrial minerals with several full-scale units installed to recover particles up to and exceeding 3,000 microns diameter. More recently, sulfidebased test work has shown that this novel device is also capable of recovering metalliferous values at a grind size that is much coarser than currently used in industrial concentrators. In the current study, high resolution X-ray microtomography (HRXMT) was used to experimentally compare the degree of exposed grain surface area necessary to recover coarse particles using the HydroFloatTM technology to that attainable using a traditional mechanical flotation cell. The data indicate that exposed grain surface area is a critical factor for coarse particle flotation. For the gold-bearing sulfide ore examined in this study, the HRXMT data suggest that near complete recoveries of coarse (850x500 µm) multiphase particles containing as little as 1% exposed grain surface area were realistically attainable using the HydroFloatTM technology. As such, this new technology may offer a unique opportunity for increasing concentrator capacity by increasing the primary grind size needed for rougher/scavenger separations.

Jan 1, 2016

By T. O. Llewellyn

The Bureau of Mines, U.S. Department of the Interior, conducted studies to recover phosphate from four dolomitic southern Florida deposits not currently mined. The samples contained 5.8 to 10.2 percent P205 and 1.7 to 1.8 percent MgO. Chemical analyses of sized fractions indicated that no pebble concentrate (plus 1.2 mm) could be produced from these samples. A scheme was developed that consisted of desliming, grinding, scrubbing, and redesliming the ore to produce a flotation feed. Conventional one-step fatty acid-fuel oil batch flotation tests on the samples resulted in concentrates containing 29.0 to 31.3 percent P205 at flotation recoveries ranging from 72.4 to 96.1 percent of the flotation feed. The MgO content of the concentrates ranged from 0.47 to 1.36 percent. Continuous flotation of the Manatee No. 2 sample indicated that commercial-grade phosphate concentrates analyzing 31.3 percent P205 and 0.55 percent MgO could be produced with a flotation recovery of 89.9 percent. The MgO content of concentrates obtained from the Manatee No. I and Hardee samples was 1.20 to 1.36 percent, respectively. Leaching with aqueous SO2 reduced the MgO content of these phosphate concentrates to 0.5 and 0.8 percent, but with a concomitant loss in phosphate recovery.

Jan 1, 1983

By Ramani R. V

There are many important physical phenomena in mine ventilation which involve transient mass and heat transfer processes. These processes have been modeled using differential equations often solved with close form solution. Within the last two decades, many numerical schemes have been devised to solve these mass-transfer problems. Much of this effort has focused on variants of the finite element and finite difference methods. In this paper, the solution of mass transfer models in mine ventilation by finite difference technique is discussed. Specifically, the computational effort and the accuracy of the solution are presented.

Jan 1, 1988

Although the mining industry faced ever-increasing risks and uncertainties in 1974, it nevertheless pushed ahead with considerable rapidity in exploring and developing new orebodies-while expanding and improving the technologies of mining and exploration. Prepared by the SME Mining and Exploration Division, this section of the annual review covers the pertinent worldwide developments in the fields of geochemistry, geology, geological engineering, open pit mining, underground mining, rock mechanics, operations research, and solution mining.

Jan 2, 1975

By M. L. Jeremic

"The syngenetic and epigenetic mechanics of sedimentation and deformation of coal seams resulted in various types of internal structure, as listed below:TYPE I-massive structure with evenly distributed coal constituencies of integrated mechanical properties.TYPE II-broad-banded structure, with bright and dull coal bands of differential mechanical properties.TYPE III-heterogeneous structure, with sheared coal bands and partings of sectional mechanical properties.TYPE IV-contortional structure, with refolded coal layers and deteriorated mechanical properties.TYPE V-porous structure of orogenically crushed and pulverized coal, with disintegrated mechanical properties.The study suggests criteria for the estimation of coal seam internal structure (gamma-gamma density log and cracks density log), which might be related to the evaluation of strata stability and coal mineability.IntroductionIt is common knowledge that coal seams have various internal structures due to different syngenetic and epigenetic events. Investigations of the internal structure of coal seams have been carried out in the coal fields of Western Canada, as follows: geological field studies of coal-bearing strata;?,geophysical borehole surveying studies;?,geological borehole logging and crack density;?,underground phenomenological studies of mine structure;?,chemical coal analysis; and?,mechanical testing of coal samples.These investigations eliminated a large number of criteria previously established for the estimation of coal seam internal structure and indicated that, from an engineering point of view, only two of them are sufficient:(I) density of seam profile (inferred from gamma-gamma log);(2) density of crack s (inferred from geological log).On the basis of these criteria, five main structural types of coal seams have been classified, which might be related to mechanics of deformation and ' failure of mine structures."

Jan 1, 1982

By J Zhou

Based on the mineralogical characteristics and mineral processing techniques required, gold ores can be classified into 12 types, including gold placers, quartz vein-lode ores, oxidized ores, silver-rich ores, iron oxide copper gold ores, porphyry copper gold ores, iron sulphide ores, arsenic sulphide ores, antimony sulphide ores, bismuth sulphide ores, telluride ores and carbonaceous sulphide ores. The bulk mineralogy and gold deportment of each ore type is different and may have a significant impact on ore processing and metal extraction. This paper summarizes the bulk mineralogy and gold deportment in some major types of gold ores and discusses the potential impact of gold deportment on gold metallurgy.

Jan 1, 2011