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By David Allen Jones

A depleted county gravel pit was rehabilitated by contracting an artist to convert it into sculpture, rather than using traditional reclamation methods. The sculptor's ideas were generally implemented as designed, but problems arose because of a faulty survey and severe weather. Public reaction was critical. A design symposium was presented by retaining six artists to prepare designs for varied sites. A public forum was offered and video-documented for broadcast. A new art-reclamation project grew out of this project.

Jan 1, 1981

By Fadeela Saloojee, Frank K. Crundwell

"Pressure leaching is an option for copper recovery from chalcopyrite. Leaching takes place at high temperatures and pressures in the presence of an oxidising agent. This work shows how the performance of pressure leaching circuits may be improved by optimising the configuration of autoclaves and the heat-removal method. The objective was achieved by creating an autoclave model by combining mass balances, energy balances and population balances. A base-case circuit consisting of a single autoclave was chosen, and this base case was compared with options for increasing capacity by adding more autoclaves to the circuit. These capacity–increase options include circuits in which the additional autoclave is added in parallel, in series and in series with thickening between the two autoclaves. The copper extraction, productivity and cooling requirements for these options are compared. The series circuit with inter-stage thickening has the highest extraction and productivity, however, the cooling duty in the first autoclave is high. In addition to comparing circuit options, three options for heat removal were investigated: cooling coils, quench water and flash recycling. The flash-recycle option results in the highest copper extraction, and the quench-water option gives the lowest copper extraction. INTRODUCTION Background Copper sulfide ores and concentrates containing chalcopyrite are typically hard to leach under atmospheric conditions. Smelting of these ores may also be a challenge, due to the inability of smelting processes to handle low-grade ores, as well as impurities such as arsenic and antimony. Alternative hydrometallurgical routes to treating chalcopyrite are therefore required. One option is pressure leaching, which is the focus of this work. In the pressure leaching process, sulfide ores and concentrates are leached in autoclaves at temperatures of 200 to 220°C and a pressure of about 3000 kPa (Schlesinger et al., 2011). An oxidising agent, usually oxygen, is required to oxidise sulfide ions to sulfate ions. The oxidation of sulfur to sulfate is exothermic; consequently, a method of heat removal is necessary in order to maintain the temperature in the autoclave."

Jan 1, 2015

By I. W. Farmer

High horizontal stresses and high horizontal to vertical in-situ principal stress ratios in the plane of underground drifts and entries can damage weakly laminated roof rocks quite severely. Such stresses are difficult to measure accurately, as illustrated by case histories of in-situ stress measurement at Wistow and Lea Hall mines, in the UK. Their direction and relative magnitude can, however, be estimated from the absolute velocity vectors of continental plates. With the preliminary results from the World Stress Map project now available it is possible to indicate mining areas where regional horizontal stresses are low, such as Europe, and high, such as Australia and Asia

Jun 19, 1905

By H. Guo

There are a number of methods available for the determination of the fracture toughness of rock. Some of the most recognised methods include the hollow pressured cylinder, the short-rod, the chevron - edge-notched round bar in bending and the disc-shaped compact specimen. Most of these tests are difficult and expensive to conduct. In this paper the simple Brazilian testing of discs for tensile strength has been used to determine their fracture toughness. Tests were conducted on six different rock types and the values of the fracture toughness obtained for each type are in close agreement with the results of the well recognised the chevron edged types. Details of the tests, and analytical validation of the technique, are presented

Jan 1, 1992

By I. A. Mwamba

Titanium sponge, which is almost pure titanium, is extremely ductile and not easily processed into titanium powder. One method of producing powder is the hydride-dehydride (HDH) process, where titanium sponge is hydrided to form brittle titanium hydride (TiH2). Titanium hydride is easily milled to produce powder and is then dehydrided to form Ti powder. In this work, titanium hydride powder obtained from titanium sponge was used as a starting material for blending and mechanical alloying with elemental powders. Firstly, titanium hydride powder was blended with aluminium elemental powder to produce a homogenized powder, which was then compacted and sintered to produce powder metallurgy compacts. Secondly, titanium hydride powder was mechanically alloyed with aluminium elemental powder and then compacted. The mechanically alloyed powder was characterized in terms of particle size distribution, morphology and microstructure. In both blending and mechanical alloying, the green compacts were characterized by assessing the green density, while the sintered compacts were characterized by their sintered density, microstructure, and hardness. The two processes have resulted in the formation of TiA13 intermetallic compound. It was established that by simple mixing and homogenizing, titanium hydride can be used as a starting material to produce powder metallurgy components in which porosity is a benefit rather than a problem, much akin to metallic foams. From the products obtained in the TiHz-Al system, it appears that titanium hydride can be used as a precursor in mechanical alloying. However, the possible formation of complex hydrides may introduce detrimental properties, and needs to be further investigated. For the production of non-porous components, it would be advisable to dehydrogenate the TiH2 powder before milling i.e. producing titanium powder by the hydride-dehydride (HDH) method. Keywords Mechanical alloying, titanium hydride, titanium aluminide and blending

Jan 1, 2011

Acid soluble calcium is depleted in drainage sediments from hydrothermal alteration centres in the Coromandel Peninsula. The routine analysis of acid-soluble calcium on drainage samples is an economical and effective technique for outlining hydrothermal alteration centres in volcanic terrains.

Jan 1, 1979

By M. P. Ristenbatt

A new automated post-disaster signaling system, intended to use through-the-earth EM propagation, was demonstrated in the laboratory at an input SNR of -34 dB. The system presently available requires an input SNR of +6 dB, and uses a human-ear detector. The work here demonstrated coherent integration, for the automated system, in multiples of 17 s, up to 1088 s (18 minutes). A repeating pseudorandom (or pseudonoise) signal is used, which offers an ideal auto-correlation at the receiver matched-filter output. A novel decision-variable algorithm achieves the estimate of noise level by using those matched-filter output samples that occur between the signal auto-correlation peaks. This work included corraboration that the received signal power decreases as distance to the tenth power, for through-the-earth propagation. Thus, the above 40 dB reduction in required input SNR permits an automated system to have a range 2.5 times that of the present system. In addition, an automated system permits the possibility of operating receivers around-the-clock; this would reduce the initial-detection-time from a few hours (present system deployment time) to a few minutes (signal processing time).

Jan 1, 1981

By D Craw

The Old Man Range, south of Alexandra, in central Otago consists of a package of highly folded greenschist facies schist of the Wanaka lithologic association. The range is crosscut by several east to ENE-striking high angle gold-bearing quartz veins, (eg Whites Reef and Grays Reef), which were extensively worked in the late 1800s. The range is bounded on its east side by the Old Man Fault, which separates these rocks from generally flat lying and planar Caples Terrane schist. To the west of the Old Man Fault, about halfway up the range, a large subparallel, 100 m wide fault zone strikes NNW and appears to cut off the historic veins. The fault zone consists of highly sheared and folded rocks and numerous high angle cataclasites and centimetre-scale clay gouge zones. Hydrothermal alteration is not apparent and the individual faults and shears are clay altered, possibly due to weathering, without visible quartz veins. Gold, limonite pseudomorphs after pyrite and rutile are concentrated in some of the narrow cataclasites and gouge zones. These mineralised structures are texturally similar to the gold-bearing reefs and may be structurally related. It is postulated that the NNW-striking shear zone and ENE-striking veins may be a conjugate array formed during a period of Cretaceous normal faulting.

Jan 1, 2004

Solid Energy New Zealand Limited has grown significantly since becoming a State Owned Enterprise in 1987. Exports, profit, turnover, output per employee are all trending upwards. The company has identified the management of Health and Safety as a key capability to sustain future growth, and to add value to the business. It has set a target of being the best practice in managing Health and Safety.   This paper examines the company's activities in the Health and Safety area, and how it sees that value can be added by preventing and containing losses through accidents involving people, property, process and the environment. Solid Energy is confident that a Planned approach to managing Health and Safety can achieve this. It will explore historical events, strategic changes, Health and Safety systems, Benchmarking, Performance Measures, initiatives, progress to date and challenges for the future.

Jan 1, 1997

By AIME AIME

A PERIOD of business depression and falling prices always raises questions as to the possible responsibility of the monetary or banking system. This is natural enough, for it is agreed that the supply of money or credit is a very important factor in modern business and in prices. However, it is far from being the only important factor. One of the chief merits of the gold standard is that under its workings the supply of currency and credit is regulated automatically to the masimun extent, in- stead of by the control of any arbitrary authority. The supply of new gold comes from the mines, and mining is free. It is distributed among the countries by the currents of trade and the play of economic forces, with the general result that the distribution tends to be in accordance with the economic development of the countries and their ability to use it or command it. Inasmuch as the accumulated stock of monetary gold is very large in comparison with the annual additions, the total avail- able supply changes but little from year to year, and it may be assumed that price-changes that are properly chargeable to gold will take place gradually rather than suddenly.

Jan 1, 1930

Flat jack stress determinations in selected colliery roadways have revealed a range of measured stress from 330 lb/sq. in. tension to 3,750 lb/sq. in. compression. Photoelastic examination of loaded plastic and actual rock model mine openings has shown that the primary horizontal stress required to attain these measured stresses would be from one to three times the superincumbent vertical load.Examination of roof movement with a borehole extensometer and a series of anchors at various horizons to 30 feet in a vertical roof borehole showed that when a standing face was advanced the roof movement was practically confined to the lower two feet. The majority of this movement occurred during the 36 hours after mining at this face commenced.The use of a radioactive isotope and a scintillation counter in a pair of parallel boreholes is a sensitive and accurate method of roof bedding plane crack detection.INTRODUCTIONA knowledge of strata stresses is required to understand the deformation of an underground opening and, in particular, the roof behaviour. It is the aim of investigations currently being conducted by Australian Coal Association (Research) Ltd. to determine the stress existing around mine openings and the location and magnitude of roof movement.STRATA PRESSURE MEASUREMENTMost measurements of strata stress are performed at the surface of underground openings and the majority measure the change of strain resulting from stress relief. The accuracy of the measured value of stress depends upon knowledge of the rock modulus of elasticity. The flat jack method has the advantage that strain relief is restored by a measured stress applied directly by the jack. The rock modulus of elasticity can also be determined.

Jan 1, 1963

By D. Harrington

Seldom, if ever, has any mining hazard presented itself that some method has not been devised to control it to some extent; the degree of success of such control depends largely upon the intensity of desire to prevent suffering, injury, and death. The economic saving to be realized and the more definitely this is realized by all concerned, the more quickly and effectively will the hazards be handled is an important incentive to prevention of accidents. Preventing coal-mine explosions is by no means a complex problem; all that is necessary is sensible, conscientious, sustained effort. The fact that explosions can be prevented has been well-demonstrated by the record of the post few years; the average annual death toll from explosions for the 5 years 1906-1910 was 438, and for the 20 years prior to 1929 it was 265: during the past 4 years an average of only 32 deaths per year resulted from this cause, although the annual production during that time varied but slightly from that of 1906-10. This is a truly remarkable reduction, and if other types of mine accidents had been reduced in the same ratio only about 300 would be killed annually in our mines instead of the nearly '1,300 killed in 1936 and the approximately 2,000 killed annually for many years. Although frequency of occurrence of explosions has not lessened greatly during the last decade, their severity decreased markedly, which would indicate that effective means are being taken to prevent the spread of explosions, even though ignitions and their causes are not being handled nearly as effectively as they might or should be handled. Several large coal-producing States, which in the past have experienced numerous disastrous explosions, have been free from such disasters for continuous periods as long as 8 years in the relatively recent past. The application of rock dust to underground surfaces has been an important factor in preventing widespread explosions; some of the mast dangerous mines have been rock-dusted fairly adequately, and this has been amply repaid in the reduced severity of explosions, as heretofore indicated; however, many have applied rock dust apparently without giving much consideration to the amount required to prevent

Jan 1, 1938

By Janis A. Shandro

The mining sector is a major economic driver for Canadian, and British Columbian communities. In parallel strong commitments have been made by industry to the well-being and sustainability of associated communities. However, these dimensions are the least understood. Especially lacking are focused regional investigations that compare the well-being and sustainability of communities dependent on different resources sectors. It is hypothesized that this type of comparative analysis will help to foster a greater understanding of what makes a resource or mining community healthy and sustainable. This paper describes research that examined community-level indicators associated with well-being (e.g. education, income and employment) and sustainability (e.g. economic diversity). The indicators were derived from Canadian Census data for 31 British Columbia resource-based communities (with a focus on mining) during a period of time (1991 to 2001) when resource sectors experienced an economic downturn. Our findings identify that during this decade, mining communities differed significantly from other resource-based communities, and comparative analysis of census derived indictors illuminate challenges that mining communities in British Columbia face with respect to wellbeing and sustainability (such as economic diversity, unemployment, and population loss). To contribute to the mining sector?s efforts towards meeting their commitments to communities, this paper concludes by proposing strategic opportunities aimed at the enhancement of mining community sustainability for policy-makers, communities, and the mining industry to consider.

May 1, 2011

By Donald Leroux, Dave Scott, Giovanni Di Prisco

"The Lady Loretta lead-zinc deposit in Northwest Queensland, Australia contains an average of 5.9% lead, 17.1% zinc and 97 g/t silver. Ore mineralization is mostly comprised of fairly complex intergrowths of pyrite, sphalerite and galena. Starting in 1998, Noranda Inc., the major joint venture partner of the project, conducted extensive metallurgical test work, which culminated in July - August 2000 in a series of Pilot Plant tests. A common thread to all the metallurgical work has been the deportment of a large portion of silver into non-payable metallurgical products. Average silver distribution from four Pilot Plants shows a distribution of silver in lead concentrate of 28%, whereas silver in zinc concentrate was 49%, and 23% in the final tails.The consistently poor silver recovery as well as the fairly unusual silver distribution, particularly in zinc concentrate, was considered an issue to be thoroughly investigated. A mineralogical plan was devised to determine if these particular metallurgical results were somewhat related to the nature and mode of occurrence of silver carriers. Work was performed to determine discrete silver-bearing minerals and/or silver contained in solid solution in a suite of commonly occurring sulphides. Ore microscopy, SEM methods, Electron Microprobe and Ion Microprobe analyses were all used to answer these questions, and to find the silver carriers, so a metallurgical plan could be devised to improve silver recovery.INTRODUCTIONPotential economic exploitation of the Lady Loretta deposit in Queensland, Australia is driven by revenue derived from zinc and lead flotation concentrates and co-product silver recovery in lead. Relatively low recoveries of payable silver to lead concentrate, and high silver distribution to zinc concentrate necessitated an investigation into the natu"

Jan 1, 2002

By Joseph Gersic

MINFO has been developed to serve as a frontend for three databases created to store basic minerals information gathered during the minerals resource assessment conducted by U.S. Bureau of Mines(USBM) for the Malheur and Jordan resource areas of southeastern Oregon(MJRA). The primary database is the Minerals Location Inventory (MLI.DBF) which contains of information assembled from field work performed during this project, the USBM Minerals Availability System/Mineral Information Location System(MAS/MILS) database, the Oregon Department of Geology and Mineral lndustries(DOGAMT) Mineral Information Location(MILOC) database, and the U.S. (Geological Survey(USGS) Mineral Resource Database System(MRDS), In addition, assay results are contained in the geochemical database (ELEMENTS.DBF) and modified X-ray diffraction analysis information is contained in the minerals database (MINOR.M.DBF). MINFO includes four types of program modules: ? Enter/Edit Data was developed to allow the addition of new information and to encourage correction of errors by providing a convenient means of entering and editing data and a large degree of automatic checking and filtering of entries. ? ACAD/DBF Link links each site symbol posted on the map in the drawing file to a record in the database. This provides the user with the ability to use a mouse or other pointing device to graphically select a site for viewing and editing. Edits are performed directly in the database file, ? Reports contains 7 formats of data output for creating files for printing, transfer to other database formats, and exporting to other software packages such as spreadsheets and word processing programs. ? Maps includes 5 programs for creating AutoCAD script files which can be used to create maps of selected information in conjunction with AutoCAD. Mineral location mapping files derived from MLI.DBF can be created in 2 formats. Mapping files can be generated from each of the 2 sets of geochemical analyses contained in ELEMENTS.DBF. X-ray diffraction analyses can also be translated into instructions for creating and posting piecharts at sampling sites.

Jan 1, 1994

By Roger E. Burleigh

In June, 1989, the U.S. Bureau of Mines, undertook a 9-day evaluation of the tin resource potential of the Sleitat Mountain tin deposit. Significant tin-tungsten mineralization is associated with quartz-topaz-white mica-tourmaline greisen alteration of a multi-unit, 57 Ma, peraluminous, granite stock which intrudes Cretaceous Kuskokwim Group flysch deposits. The granite comprises marginal biotite-, intermediate biotite-muscovite-, and central zinnwaldite-granite units, interpreted as a zoned alteration system. Major vein mineralization is confined to two east-west-trending zones of steeply oriented tabular lenses of greisen interleaved with mildly altered granite. Cassiterite is the dominant ore mineral while arsenopyrite, loellingite, wolframite, pyrite, sphalerite, chalcopyrite, and bismuth-oxides are present in minor to trace amounts. The north and south greisen zones are estimated to contain an inferred resource of 128 to 212 million lbs Sn in 28.6 million st of mineralized rock. An 1,800-lb representative bulk sample contained 0.37% Sn, 0.04% W and 17 ppm Ag and is considered an average grade estimate for the deposit. Drill testing by Cominco Alaska Exploration indicates that substantial widths of high-grade tin mineralization are included within the lower grade disseminated mineralization. Depth of deposit erosion is substantial and there exists a high probability for placer tin deposits.

Jan 1, 1991

By C. F. Jackson

This paper has been prepared as a progress report in connection with the series of articles on mining methods and costs which are being published by the U. S. Bureau of Mines in the form of information circulars. When enough circulars have boon completed it is planned to publish a more complete and comprehensive paper in bulletin form dealing with the subject of underground transportation. Progress reports, followed b., bulletins, will be prepared from time to time dealing with other subjects included in the general study of mining methods at individual nines, such as mine development, drilling, and blasting; stoping methods (each principal stoping method to be summarized in a separate paper); Ventilation; wage, contract and bonus systems, etc.

Jan 1, 1931

By K. L. Murphy, G. Multamaki, P. M. Huck

"A preliminary evaluation, based on existing data, has been made of the implications of placing radium-barium sludge in tailings areas. The study was restricted to a consideration of possible increases in the quantities of radionuclides escaping to the environment through either groundwater or surf ace water, considering the types of tailings treated and the effluent treatment systems currently operating in Canada.IntroductionIn the recovery of uranium from ore deposits, the tailings produced by mine/mill complexes are conveyed to impoundment areas in slurry form. After settling, the supernatant is discharged to the environment together with runoff from precipitation on the tailings bas in. Currently, all operating uranium mines in Canada employ barium chloride treatment to control the release of dissolved radium to the aquatic environment. The dissolved radium in the tailings decant is precipitated with barium chloride, forming (Ra,Ba)SO4, and allowed to settle in ponds or lakes. In some instances, settling tanks have replaced ponds and flocculants have been added to aid settling. Because the Atomic Energy Control Board does not consider the precipitation ponds to be suitable for final disposal of these sludges, acceptable sites must be found. Options which have been suggested for sludge management include underground placement either in worked-out mine areas or in special chambers, or placement in the tailings areas. Conceptually, the latter alternative is attractive and probably would minimize sludge handling. This alternative would be subject to the AECB policy which requires that upon abandonment, radioactive releases from a tailings area must be within present regulatory limits and that treatment to meet these limits should not be required in perpetuity.No quantitative data exist concerning either the effect of physical and chemical conditions in the tailings on resolubilization of radium from precipitated sludges or the fraction of this additional radium which would be released."

Jan 1, 1982

By Abdurrahman Cetinbas

The effect of water infusion on the flow of methane and on the production of dust was investigated at an active face in the Pittsburgh coalbed. The average total flow of methane at the face decreased by approximately 79 percent, whereas the flow from the ribs increased about 24 percent after infusion. On the day after infusion, dust concentrations appear to have been reduced; however, the presence of large quantities of rock dust obscured the results on the following days.

Jan 1, 1972

By Baha Abulnaga

Slurry pipelines are used in a number of countries to convey processed ore mixed with water over long distances from remote mine sites to ports or plants for further processing. In Egypt and Sudan, numerous mineral resources are scattered in remote areas. Through the years, Egyptian geologists have identified 268 sites for metallic ores and 386 sites for industrial nonmetallic minerals. A large portion of these sites are in the Eastern Desert in an area called the Nubian Shield. Similar sites are found in the Sudan where mining contributes to less than 1 percent of the gross domestic product (GDP). There are three important components of infrastructure needed to develop these resources ? power, water and transportation. While Egypt is able to satisfy 70 percent of its needs in iron ore from the Gadideh Mine in the Western Desert, it needs to expand its other resources to reduce imports heavily sedimented. Dredging of these sediments and transporting them by slurry pipelines would enhance an industry of bricks or agricultural development based on tailings technology often used in mining. This article explores the potential for slurry technology for opening new mines in the desert or recuperating the sediments of the Nile. The technology by itself would be new to both countries and would benefit from collaboration, particularly to de-silt the Nasser-Nubia Lake.

Jan 3, 2010