[en] The Rossing uranium deposit is the only one currently being mined in Namibia. Construction began in 1974 and production started in 1979. Current production is close to 4800 s.t. U3O8 per annum. About 160 000 mt of ore and waste are removed from the open pit every day. Each truck load is radiometrically scanned to determine ore grade and is discharged either directly into the primary crusher or into low-grade stockpiles. The uranium is extracted in a sulphuric acid leaching plant and upgraded in an ion exchange and solvent extraction plant. An ion exchange plant recovers uranium from the tailings solution. Three thousand people are employed at the mine, most living in the nearby town site. Employee training and development are emphasized. Employee health is carefully monitored; no occupationally-related disease has been reported. Rossing contributes one third of the GNP of Namibia. (L.L.)

[en] A list of U₃O₈ production facilities compiled by the Nuclear Assurance Corporation is reproduced. Reference to the list should be made with the knowledge that it is possible for the status of a given mine to change quickly, depending on a variety of commercial, financial or political factors. The material presented reflects the information available to, and the judgement of, the Nuclear Assurance Corporation as of 30 June 1987. The status and ownership of mines throughout the world is given country, by country. (author)

[en] This paper discusses the device itself, the mechanism by which it functions and compares this mechanism with more common devices such as the mechanical roof bolt and the resin rebar system. A Friction Rock Stabilizer can be pictured as a split pipe, set into the geologic mass to be reinforced; thus, the trade name ''Split Set.'' The configuration is shown. Friction Rock Stabilizers are 1-1/2'' outside diameter as manufactured and normally are put into 1-3/8'' diameter boreholes in rock. Depending on the smoothness, diameter throughout its length, straightness of the hole and frictional coefficient, and anchorage of 4/4 to 1-1/2 tons is obtained per foot of borehole contact upon installation. The device can be easily installed with any common air percussion impact drill. The steel used in the fixture is a high formability steel with approximately a 70,000 psi yield. Wall thickness is near 0.090 inch. The stabilizer is tapered on the upper end for insertion into the borehole and on the other end a ring is welded to the unit as a retainer for the roof plate. Upon installation it provides a yieldable support and, with time, becomes more rigidly anchored in the rock to provide the restraint necessary for long term stability. It is a full contact system which preloads the rock in compression to increase stability. The yieldable aspects of Friction Rock Stabilizers without loss of restraint against the rock cannot be overemphasized. Also, the preload of the rock by the device during and after installation is very important. The preload acts in a plane perpendicular to the axis of the device and also along the axis as it is driven in. This combined effect produces a zone of triaxial compression around the device and, when coupled with the pressure bulb which is present in the rock form the plate, we end up with a unique pear-shaped compression zone around each device

[en] The 1978 issue of the Mining International Year Book marks the 91st year of publication and contains particulars of the principal and other international companies associated with the Mining Industry. The book is recognized as the foremost reference work of its kind with a coverage both wide and detailed. The many companies registered abroad are distinguished by an entry immediately beneath the title giving the date and place of incorporation; where the date of registration alone is mentioned, the company is registered in the United Kingdom. As in previous years each entry has been reviewed and, where necessary, revised in the light of additional information received since the previous volume. The information thus recorded is the latest available at the time of going to press. Special features of value and interest include cross-reference index to all principal, subsidiary and associated companies in this edition, geographical index, suppliers' directory and buyers' guide, world production table, mining areas of Australia, and professional services section

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[en] This article features the planned autumn 1983 start-up of the Key Lake uranium mine and concentrator in northern Saskatchewan. Key Lake mine has an average grade of 2.62%, and contains 28% of Canada's proven uranium reserves. Ownership is shared between the Saskatchewan government, a subsidiary of Eldorado Nuclear, and private German interests. Each of the partners is doing its own marketing

[en] The mining method by room and pillars is described there. The filling will be of high resistance. Granulates, hill-sand, water and cement will be use for that purpose. A plan of the setting-up is proposed. Pillars will be recovered after the filling-up

[en] The principal economic impacts are the result of three flows of money from the industry into the remainder of the state's economy. These are: money paid to individuals (personal income); money paid to other businesses (business income); and money paid to state and local governments (government revenues). Growth has come in a largely rural, seven-county area that lies within the triangle formed by the Laredo, San Antonio, and Corpus Christi metropolitan areas. 4 refs

[en] Thanks to some innovations and effective measures, the rope guides have been successfully used in multi-level operation in some uranium mines since the year of 1968. These innovations and measures are as follows: (1) by the use of the intermediate fixing grips of guide ropes, etc., to increase the rigidity of the guides and restrain swaying of the hoisting conveyance. (2) by the use of modified screw tensioning device to replace the weight tensioning one to cut down operation cost apparently. (3) By the use of mobile platform in the form of arc plate, or the shiftable guides as the cage stabilizer for intermediate levels to firm the cage horizontally and prevent it from vertical tilting owing to impulsive force from the motion of mine cars, etc. (Author)