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By Lam. E. K., J. W. Jarvi, B. P. Bharadwaj

"The Rabbit Lake Operation is located in Northern Saskatchewan on the western shore of Wollaston Lake approximately 800 km north of Saskatoon, Saskatchewan.The Operation is owned by a joint venture of Cameco Corporation and Uranerz Exploration and Mining Limited. Cameco is the operator.The Mill started production in June 1975 under the ownership of Gulf Minerals Canada Limited and over the past twenty years has increased the rated production capacity to over twice the original design.The Mill was originally designed to process 485,000 tonnes per year of ore with an annual production of 2.0 million kg of U308 (yellowcake). During the past ten years changes in ore sources and process modifications have led to increased milling capacity and production targets. The Mill has treated a total of 8.6 million tonnes of ore and produced over 40 million kg of U308 in the twenty year period, despite the shutdown and cutbacks in operating time since 1989.The 1995 tonnage throughput was 206,000 tonnes per year. Annual production though has risen to 3.6 million kg of yellowcake despite the departure from full-time to half-time operation in 1991 (7 up-7 down). The forecast for the coming years will see tonnage rising from 300,000 to 570,000 tonnes, production of 4.5 to 5.4 million kg of yellowcake and an anticipated return in the year 1998 to full time operation.This paper will give a brief history of the Mill and focus on the present flowsheet and recent improvements to the process."

Jan 1, 1996

By Lyman G. J

Magnetic separator operation in the recovery of magnetite in heavy medium circuits was studied by conducting a series of tests on a full size wet drum magnetic separator.The significant operational variables were found to be feed pan clearance, squeeze pan clearance, dry magnetite feed rate and separator drum speed. With feed and squeeze pan clearances optimized for typical primary separator operation, magnetite loss and concentrate specific gravity were found to be related in a regular manner to dry magnetite feed rate at any drum speed.A two component model of magnetite loss is proposed, relating total magnetite loss to losses in the feed pan and squeeze pan zones. The experimental curves relating magnetite loss to dry magnetite feed rate at the various drum speeds are interpreted in terms of the two component model.The magnetite particle size distribution in the separator was also examined. The tailings magnetite was found to be finer than the feed magnetite only when the dry magnetite feed rate was low, or immediately following the introduction of a new charge of magnetite when the separator was fed at an intermediate dry magnetite feed rate.

Jan 1, 1983

By Philip Weaver

The MIDAS project is funded by the European Commission (DG Research) and began on the 1st November 2013. The project will investigate the environmental impact of deep-sea mineral and energy extraction: specifically, polymetallic sulphides, manganese nodules, cobalt-rich ferromanganese crusts and the potential mining of rare earth elements. As deep-sea mining becomes ever closer, and the International Seabed Authority begins to develop its regulatory framework for exploitation of deep-sea minerals, MIDAS is well timed to provide fundamental scientific information. The MIDAS partnership represents a unique combination of scientists, industry, social scientists, legal experts, nongovernmental organisations and small and medium enterprises. MIDAS is carrying out research into the nature and scales of the potential impacts of mining including 1) physical disturbance of the seabed by mining, the creation of mine tailings; 2) the potential effects of particle-laden plumes in the water column, and 3) the possible toxic chemicals that might be released by the mining process. Key biological unknowns, such as connectivity between populations, impacts of the loss of biological diversity on ecosystem functioning, and how quickly the ecosystems will recover will all be addressed. The plan is to use this information to aid development of recommendations for best practice in the mining industry. A key component is the involvement of industry within the project and through stakeholder engagements to find feasible solutions. The project will work closely with European and international regulatory organisations to take these recommendations forward into legislation. A major element of MIDAS will be to develop methods and technologies for 1) preparing baseline assessments of biodiversity, and 2) monitoring activities remotely in the deep sea during and after exploitation, including ecosystem recovery. To carry out this work MIDAS is conducting a number of research cruises to examine the above issues at potential sites for exploitation of SMS and nodule deposits. This talk will present some of the recent findings of the project.

Sep 1, 2014

By L. S. Hansen

Organized efforts toward the prevention of injuries and occupational diseases have been of comparatively recent origin in the mining industry, dating generally from the beginning of this century. Mining-and particularly underground mining- is more hazardous in many respects than most other major industries, and continual and increasing attention has been given to its health and safety aspects. The importance of the physical well-being of those engaged in mining was recognized by Agricola, who, after describing the hazards encountered in 16th century mining operations, stated that "Some of these evils, as well as certain other things, are the reason why pits are occasionally abandoned." In the past 50 yr particularly, mine managements and labor organizations, separately or collectively, have mounted productive efforts toward the prevention of accidents and industry-associated diseases and illnesses. A statistical study of this period indicates that increasing awareness coupled with the endeavors of all concerned agencies has resulted in decreasing frequency of occurrences of injuries and illnesses. In recent years particularly the mining industry has used the services of safety engineers, industrial hygienists, inspectors, ventilation engineers and other specializing in locating and correcting deficiencies affecting the welfare of employees. Concurrently, the labor movement has incorporated into its organization individuals working in the fields of health and safety, many devoting full time to these responsibilities. Others serve in behalf of their fellow workmen as on-the-job safety representatives. Most authorities agree that accidents are caused by (1) unsafe acts, (2) unsafe conditions and, exceptionally, (3) Acts of God. The "unsafe act" often is cited as the prime cause. but many accidents, and attendant injuries, are the result of a blend of "unsafe acts" and "unsafe conditions," with each chargeable in varying proportions. It therefore is necessary to consider both the physical elements of the mine plant and the training, mental attributes and actions of all personnel involved. Analysis of an accident, if based on hasty reconnaissance and unduly hurried questioning, seldom will disclose more than surface causes and consequently will result in inadequate measures to prevent repetition. Mining involves unavoidable and calculated risks, as in all facets of life. It is most important then that men employed in mining be schooled in the hazards and develop fully the ability to evaluate and minimize risks. The environment, of underground mining often is harsh and strange compared to the more natural surface conditions man has learned to cope with as a part of established life patterns. The miner. therefore, must adapt to unusual situations and conditions and must develop a mental attitude permitting acceptance of change. 3.1-INDUSTRY-AFFILIATED SAFETY AGENCIES L. S. HANSEN There are many organizations primarily interested in health and safety. In addition to industry and labor groups, there are many private and governmental

Jan 1, 1973

Basic parameters affecting the stability of foams have been studied. We used the thin film pressure balance (TFPB) technique of Scheludko and Exerowa (1959) to measure the surface forces in foam films stabilized with various frothers such as pentanol, octanol, MIBC, and PPG. The results were compared with the froth stabilities measured using the shake tests and the film elasticity calculated using the model developed by Wang and Yoon (2006). It was found that the froth stability is controlled by both film elasticity and surface forces (or disjoining pressure), the relative contributions from each changing with frother concentration and type.

Jan 1, 2006

By L Spencer, H Zwingmann, I Graham, D Cendon, B Kelly, D Burkett, F Lau, P Lennox

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Kulumadau deposit represents an intermediate-sulfidation epithermal gold deposit (3.8 Mt at 2.3 g/t, Ag:Au = 1). Mineralisation is primarily confined to hydrothermal breccias within pre-existing fault zones, where it is disseminated throughout a hydrothermal matrix comprising chlorite-quartz-adularia-illite-I/S clays-calcite-pyrite. The host sequence represents numerous mid-Miocene pyroclastic flow eruptions within a tectonically active emergent shallow marine to subaerial depositional setting. Subsequent growth faulting was responsible for debris avalanches, which were subsequently cut by reverse faults. Faults were exploited by hydrothermal fluids, with the heightened porosity at the juncture between faults and debris material facilitating boiling of the ore constituents. Fluid inclusion studies suggest that fluid mixing between meteoric fluids and magmatic fluids, accompanied by boiling, were the primary mechanisms for gold deposition. The occurrence of anhydrite/gypsum as late-stage veins and their sulfur and oxygen isotopic values indicate post-mineralisation mixing of sea water with hydrothermal fluids.CITATION:Burkett, D, Graham, I, Spencer, L, Lennox, P, Cohen, D, Zwingmann, H, Lau, F, Kelly, B and Cendon, D, 2015. The Kulumadau epithermal breccia-hosted gold deposit, Woodlark Island, Papua New Guinea, in Proceedings PACRIM 2015 Congress, pp 205–212 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By N. M. Skarbøvig

Safety nets have been used selectively in several South African mines over the years. Recently, however, an increased emphasis on mine safety has seen a resurgence of their utilization underground. This renewed interest has, however, also raised questions about the design and performance of these nets and their practical applications underground; these are the subjects of this paper. Generally, mine safety nets are used to protect personnel from falling rock in temporarily supported development ends, tunnels, ASGs and stopes. These diverse applications each require specific net designs, resulting in a wide product range. As a rule, however, mine safety nets need to carry specified static or dynamic loads with the least possible deformation. Because of the application-specific characteristics of mine safety nets, there is no South African national standard for them. Consequently, neither the SABS, nor the CSIR, performs standard tests on these components. In 2007, therefore, SIMRAC made available their Savuka facility for the testing of mine safety nets; the Savuka drop test became the accepted industry test standard for mine safety nets. From late 2007 to mid 2009, Norsenet, in collaboration with SRK Consulting, the designated operators of the site, conducted approximately 200 tests, which formed the core of Norsenet's database of safety net performance under various loading conditions. The test specimens comprised a wide range of net materials and config¬urations; the materials included: high density polyethylene, polypropylene, polyester, nylon, as well as a blend of polyester and polypropylene used primarily for reinforcement ropes. Net configurations encompassed the following parameters: net type, i.e., knotted nets or sewn nets; net strand type, i.e., braids, twines, or webbing; strand size; mesh size; mesh orientation, i.e., parallel or oblique to the net edge; net edge reinforcement, i.e., knotted, tied, with or without reinforcement ropes; internal reinforcement ropes, i.e., diagonal ropes and/or orthogonal ropes; as well as net attachment options, including loops and chainlinks. From the number of variables listed above, and the limited number of tests available, it can be appreciated that the findings of the test series required careful scrutiny. Nevertheless, principal performance factors clearly emerged: besides the obvious net mesh variables, such as net strand material, strand diameter and mesh size, it was the configuration of the reinforcement ropes and their attachment to the net panel which had the strongest influence on net performance. All the structural elements of a safety net need to work together to transfer the imposed load from the net panel, through the reinforcement ropes, to the net attachment points. In this load transference chain, the weakest link limits the strength of the structure. From this development work, Norsenet has gained valuable expertise to custom-design and manufacture nets to clients' specifications. The examples presented in the paper will also show the experience acquired in the installation of nets underground. Future work will include the establishment of a state-of-the-art net testing facility at Norsenet's factory in Vredenburg.. Keywords Mine safety net, safety net, protective device, mine safety, safety net design, safety net performance, safety net applications.

Jan 1, 2011

By Desiree Willis

One of New York City?s largest subway projects is under way 43 m (140 ft) beneath the surface of downtown Manhattan. The East Side Access project, more than 30 years in the making, was halted after a partial excavation in the 1970s due to a lack of funding. The project, once dubbed the ?Tunnel to Nowhere,? has been revitalized into a groundbreaking subway line that includes unique tunnel boring machines (TBM), construction methods and muck removal systems. Project overview The East Side Access project involves construction of a new 6.7-km (4.2-mile) subway line needed to relieve heavy traffic congestion between the boroughs of Queens and Manhattan. The line will serve approximately 160,000 commuters daily between Grand Central and Sunnyside rail stations. Manhattan and Queens will be connected under the East River by the 63rd Street tunnel, a submersed double-decker tube. The submersed tube consists of reinforced concrete sections barged in place on the riverbed. The tube contains operational subway lines on the top deck, while the bottom deck (the ?Tunnel to Nowhere?) will become operational when the East Side Access project is completed in 2013.

Jan 1, 2008

By R. W. Lawrence

"Biological leaching can be used to enhance the recovery of gold and silver from refractory ores, concentrates and tailings. The method liberates precious metals associated with sulphide minerals such as pyrite and arsenopyrite making them amenable to cyanidation. The chemistry and features of biological preoxidation leaching is discussed. A summary of the results obtained on various ores, concentrates and tailings is presented.INTRODUCTIONRefractory precious metal ores in which gold and silver are finely disseminated in sulphide minerals such as pyrite and arsenopyrite are becoming more important to the mining industry. This is due both to a depletion of simpler, free-milling ores and to a significant increase in the price of gold in recent years. Whereas many ores can be directly cyanided with gold solubilizations over 90% obtained, the refractory ores respond poorly to direct cyanidation and require decomposition of the precious metal-bearing sulphide minerals to increase recoveries.Decomposition of sulphides by oxidation prior to cyanidation can be carried out by several means. The oldest method is roasting which removes unwanted ore constituents by high temperature oxidation and volatilization. In Canada, for example, roasting is used at Giant Yellowknife (Connell and Cross, 1981). Another method gaining increasing acceptance is pressure hydrometallurgy which uses aqueous oxidation conducted at high temperature and pressure. Homestake Mining Company have recently completed construction of a plant incorporating pressure oxidation at their Mclaughlin property in California (Guinivire, 1984)."

Jan 1, 1985

The project to reopen the Tasmania Mine has centred around efforts to reopen the Hart Shaft to access the high grade reef remaining below the old workings, which extend down to 457 in. Efforts in 1982 and 1987 were frustrated by unstable clay ground around the shaft, which resulted in significant subsidence of the shaft collar and lining. A successful program has since been implemented to solve the problems, stabilize the collar and recover the upper shaft which had collapsed down to 90 m.

Jan 1, 1989

The only economically significant deposit of dolomite in New Zealand is at Mount Burnett, in north-west Nelson. The dolomite, associated with marbles and schists, is complexly deformed, and is of Paleozoic age.A very large quantity is present, although the recoverable amount is to some extent limited by the difficult terrain.Physically the quality of the dolomite is excellent. It is a tough, durable, fine grained rock. Chemically it is a little more variable. The range and frequency o~ the more important impurities are illustrated by hlstograms, as is the "dolomite factor"-a measure of the amount of the mineral dolomite in the rock. lbe dolomite factor averages 84 per cent, the remainder of the rock consisting largely of calcite. Quarrying, milling, production, and uses are described. In 1966 production reached 13,250 tons.

Jan 1, 1969

More gold is being produced now than ever before in recorded history. All over the world huge quantities of ore are being mined and processed, thanks to historically high prices for gold and the use of processing techniques demonstrated as cost efficient in the last 20 years. Over the past 10-15 years prices for many other metals have been depressed, and gold has accounted for a significant proportion of worldwide exploration and development expenditures(l)1. The revenues generated from gold mining are providing greater return on investment, more jobs, and more tax revenues to national governments than ever before. Emerging nations are using the gold industry as a springboard for development; developed nations are continuing to fuel their economies with gold industry revenues; and China and countries of the former Soviet Union are using the gold industry to generate foreign exchange, modernize their mining industries, and take the first tentative steps toward private sector participation in their economies.

Jan 1, 1994

By Zhitao Ma

The Cast-in-place Concrete thin-wall Pipe pile, referred to as PCC pile, is a new kind of pile for soft ground improvement. In this paper, firstly, the general introductions of the new pile technique, mainly including the technique principle, the structure of pile-driving machine, and the technological process were given, then based on the results of in-situ static lateral loading test, the pile lateral capacity, the relationship of load-deflection of pile at the ground surface, the lateral deflections versus depth and the soil reaction along the pile shaft were analyzed.

Jan 1, 2006

By F. Djahanguiri

The U.S. Bureau of Mines is conducting research on underground stope leaching of metalliferous ores to minimize the environmental impact of ore processing on the surface and to maximize minable reserves. An aspect of this research is to minimize pregnant solution losses and/or groundwater contamination by leach solutions. Bulkhead design and construction are important issues for solution control and stope leaching economics. A reinforced concrete bulkhead was designed, constructed, and tested for solution control in an underground mine near Idaho Springs, CO. This paper presents the bulkhead design methodology and construction procedure.

Jan 1, 1995

By T. A. Klinefelter

KYANITE and the related minerals sillimanite, andalusite, dumortierite, and topaz are natural aluminum silicates that can be used in production of mullite (3A1203?2Si02), a superduty refractory material. Kyanite and sillimanite are the dominant ones because of their greater abundance. The only other kyanite-group mineral presently used for mullite production is andalusite. Mullite is not an absolutely essential material as other refractories can be used in the same heat range. However, it is a highly satisfactory one. It is the only compound of silica and alumina that is stable at high temperatures. It has low thermal expansion and is very resistant to corrosive melts and to thermal shock. For these reasons mullite refractories have a much longer life than standard fire-clay refractories under the same conditions. Worldwide, excluding U.S.S.R., the refractories industry consumes about 150-000 short tons annually of kyanite group minerals and synthetic mullite.

Jan 1, 1961

By Ronald J. Mathis

The objective of this contract is to design, build, surface test, and evaluate a breadboard prototype of the Variable Wall Mining System so that data are available for the design of a production machine. The Variable Wall Mining System (VWMS) consists of a series of side cutting augers, connected end to end, and distributed across a panel. Supplying rotary power at the end of the string and anchorage from conventional longwall roof supports, the augers are sequentially thrust into the face and then lifted to the roof to extract the coal in a continuous manner. The augers not only cut but also transport the coal. The effort described in this report summarizes the operation characteristics of the VWMS, the design methodology used to develop various working models, the surface testing of a ½ -scale version of the VWMS, prediction of power requirements and performance potential of a full-scale system, and a critique of the VWMS concept, conclusions, and recommendations.

Jan 1, 1987

By Y. Z. Xu

This paper presents a new dynamic method called Resonant Pile Test (HPT) for evaluating bearing capacity of pile. The basic conception of RPT is given in brief and the measuring system is also introduced. In addition, the influences of the magnitude of exciting force and of the mass of pile cap on test results are discussed. Finally, comparisons between values of bearing capacity given by RPT and by static load tests for a variety of pile types are listed.

Jan 1, 2010

By George K. Schenck

This Bureau of Mines publication describes and evaluates a Standard Industrial Classification (SIC) based end-use data system for minerals that is designed to link the demand for minerals to economic activity in commercial uses. The new data system is two-dimensional. The first dimension of technical product classes (TPC's) measures the consumption of minerals in major primary intermediate products. The second dimension measures the consumption of these TPC's in SIC end-use sectors in sufficient detail to identify the major determinants of demand for each TPC. Intercomodity comparisons are achieved at the level of SIC two-digit major groups. The methodology was developed so that all available sources of information from Government and industry can be utilized at minimum cost. This information will be supplemented with additional data to be obtained by modifying existing Bureau of Mines canvasses so as to elicit additional quantitative responses from mineral producers. The new data system is expected to improve significantly the ability to forecast demand for minerals, and provide an information base that would, for the first time ever, permit resolution of such questions as trends in substitution among materials and the intensity-of-use of materials in end-use sectors. For the 42 TPC?s identified in the report, data are available for the new system from current sources or, except for three TPC?s that require new canvasses, can be obtained by modification of existing Bureau canvasses.

Jan 1, 1982

By A. E. Soregaroli, H. D. Meade

"The Keystone porphyry molybdenum deposit, located in southcentral British Columbia, is hosted by intrusive rocks of the Cretaceous Mount Lytton batholith and the early Tertiary Keystone quartz diorite stock. The molybdenite mineralization is associated with rhyolite porphyry dikes flanking a large 1300 m by 2100 m breccia complex. Recognition of the potential for the buried molybdenum porphyry system was based on quartz-molybdenite vein fragments within the hydrothermal breccias.The full extent of the molybdenum mineralization is not known. The few deep drill holes along one comer of the breccia complex defines strong metal zoning of molybdenum and associated elements of F, Mn, Zn, Pb, Au, Ag, Fe and W about the molybdenum stockwork mineralization that may be useful for guiding additional exploration. The best mineralization occurred near the base of the deepest drill hole with 0.114% Mo in rhyolite porphyry near the edge of the breccia pipe at a depth of 1350 m.The exploration history of the deposit has been complex, focussing on both porphyry-style mineralization and precious metal veins and stockworks on the periphery of the porphyry system. Exploration to date has defined an attractive porphyry molybdenum system with uneconomic grades at great depth; however, there remains significant potential to define economic mineralization elsewhere in the Keystone porphyry system and adjoining occu""ences."

Jan 1, 1995

By Anthony Spencer

The mining industry internationally seems on the verge of a major underground support revolution as suppliers, mines, consultants and researchers develop, test and use thin support (structural) membranes (or superskins) Membrane support in the form of shotcrete has been used since the 1950s in underground mines. Shotcrete (sprayed concrete) is generally applied at a thickness depend on the need. There is, however, considerable confusion concerning such support technology, and this paper attempts to clarify certain aspects, and dispel certain misconceptions and myths about the support membrane needs and advantages influence the thin membrane uses underground.

Sep 13, 2001