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By R. W. Raymond

HAVING had recently the opportunity of examining a transit and a plummet-lamp, manufactured by Messrs. Heller & Brightly, of Philadelphia, and intended for the use of mining engineers in under

By Frank F. Aplan, Robert S. Thomson

A placer ore jig, typically used to recover fine gold, tin and diamonds from alluvial ores, has been modified to remove fine pyrite from minus 6.4 mm (-114 inch) coal. In parallel tests, it proved to be far superior to two conventional coal jigs, the Baum and the Baum-feldspar, in removing fine pyrite from coal. The Pan-Am placer jig was found to remove essentially all of the +28 mesh pyrite and from 99% to 90%, decreasingly, in the 28 to 200 mesh range. This jig also showed a superior performance to the Baum-Type jigs in removing fine coal from its associated refuse. The superiority of the Pan-Am placer jig is related to the strong emphasis given on the suction stroke and, hence, on consolidation trickling, whereas the Baum jigs principally emphasize the pulsion stroke during jigging.

Jan 1, 1995

By Charles R. Keyes

In the dry regions of the globe many silver-deposits display certain remarkable features, which at the same time are so totally unlike anything met with among ore-bodies elsewhere that they hare long presented exceptional dificulties, not only to a satisfactory explanation of their origin, but to economical milling. A most striking peculiarity of these ores is the haloid character of many of their bonanzas. To this fact more than to any other may be ascribed most of the unusual uncertainties of mining-operations in desert countries—the marvelous local richness of the ores under certain conditions and the often abrupt transition to utter poverty; the inadequacy of ordinary prospecting customs and the constant devising of new exploratory methods; the unaccountable losses in smelting and the continual change in treatment-practice. For these anomalies certain climatic conditions seem to be chiefly responsible.

Jan 1, 1912

The confusion caused by the different numerical representations of time in the ever-increasing international exchange of information has underlined the need for a world-wide uniform representation of time.

Jan 1, 1989

Publications of the 13th CMMI Congress, by J.T. Woodcock (editor-in-chief). Melbourne, Australasian Institute of Mining and Metallurgy, 1986. Set $A90,00. Reviewer: J.D. Austin

Jan 1, 1988

By Dominigue Francois-Bongarcon

This paper presents a step by step vulgarized review of the applications of geostatistics to the estimation of the mineable, recoverable reserves of the Cinola gold deposit in British Columbia.

Jan 1, 1988

By J. B. Nau

A short time ago some interesting experiments concerning a new steel-making process in the open-hearth furnace were made by the writer at the Croton magnetic mine, N. Y.

Jan 1, 1892

By Martin JD, McNicol JH

The electrolytic zinc plant at Port Pirie South Australia, was designed and constructed to treat zinc oxide fume recovered by treatment of lead blast furnace slag in two fuming furnaces, The plant was commissioned in late 1967. The equipment installed and the oper- ating procedures adopted,'are described in some detail.

Jan 1, 1975

By Michael Brittan

The Delkor Linear Screen represents an important screening innovation in the minerals industry. Applications geared to the enhancement of gold processing efficiency through coarse screening are presented. Recent developments in the use of the Linear Screen as a fine screening classification device in mill circuits are also discussed.

Jan 1, 1998

Book news 1. Book reviews ? Prospecting in areas of desert terrain. London, The Institution of Mining and Metallurgy, 1985. 283 pp. £28 (members £25,20). Reviewer: J.S. Mostert This publication records the proceedings of a con¬ference convened to deal exclusively with prospecting in areas of desert terrain. The meeting, organized jointly by The Institution of Mining and Metallurgy (London) and the Ministry of Energy and Mines, Morocco, was held in Rabat from 14th to 17th April, 1985, and generated considerable international interest. Exploration cam¬paigns and case studies of successful discoveries in the desert areas of more than 14 lands are described. Since large areas of South Africa, Botswana, and Namibia are characterized by and and semi-arid terrains, this publication should be of considerable interest to explorationists and mining engineers engaged in the search for and development of mineral deposits in southern Africa. The fact that the desert terrains of southern Africa are host to a number of important base-metal (Aggeneys, Gamsberg, Prieska, and O'Okiep) and diamond deposits (Orapa, Jwaneng) has ensured continued interest in these areas from the viewpoints of exploration and mining.

Jan 1, 1985

LUTHER B. EAMES, Pueblo, Colo. (written discussion*).-In reading Mr. North's interesting paper, several points have been noted that appear to warrant discussion. With a feed all through 20 mesh, I feel inclined to question the use of steel balls as large as 2 in. in a tube mill. I have seen balls as small as-3/4 in. used for the dry grinding of cement clinker, and surely many more points of contact would result from smaller balls. This would seem to be desirable in a mill as short as 6 ft. The heavy load in the classifiers would also indicate a high proportion of returned pulp. I hope that some discussion by Mr. North -and others may develop this point. The flow sheet on page 1181 shows the solution returning from the dam valued at 40 c. per ton being added to the last decantation tank. Theoretically, this solution should not be added to that of a lower value. As I calculate it, if this solution were added to tank X the solution finally discharged from tank Z would be reduced in value by nearly 4 c. per ton.

Jan 10, 1919

By J. A. Muñoz

In this work, short and long-term tests were performed using different massive mineral sulfide specimens (chalcopyrite, pyrite, sphalerite, galena, covellite and chalcocite) of museum grade and quartz of analytical grade in an acid medium containing silver ions. After attack, the samples were observed by SEM and products characterized by EDS. Parallel, massive specimens of pyrite (FeS2) and chalcopyrite (CuFeS2) were embedded in an epoxy resin, either electrically isolated or in electrical contact, and treated with silver ions in the presence of bacteria. Finally, massive chalcopyrite and pyrite electrodes were subjected to electrochemical measurements in an acid medium under different experimental conditions (addition of silver ions and inoculation). The results showed that silver deposition takes place preferentially on specific mineral surfaces: chalcopyrite, galena, covellite and chalcocite. The chemical reaction of silver ions with pyrite and sphalerite was negligible at low silver concentration (8 ppm). But sphalerite reacted with silver ions at higher silver concentration (100 ppm). In a mixture of chalcopyrite and pyrite, silver was deposited on the former surface creating new cathodic sites which sped up the electrochemical reactions of chalcopyrite dissolution.

Jan 1, 2007

Ranger Uranium Mines Pty. Ltd. operates an open pit mine and ore treatment plant in the Northern Territory designed to produce 3 000 tonne/yr of U308 in yellowcake from 3 500 tonne/day of mill feed. The construction of this project was completed in 1981, 12 years after the discovery of the orebody. Wright-Davy, a Joint Venture of Wright Engineers and Davy McKee Pacific, were the Project Managers and Designers of the $270 million ore treatment plant and associated infrastructure. The project was designed in Sydney in -an office integrated with the Client, staffed by 35 key personnel drawn from Wright Engineers and Davy McKee, supplemented by personnel hired for the project. The peak Wright-Davy workforce in Sydney of 200 contained 113 design staff. The design principle of using the best practicable proven technology resulted in a plant which easily produces its design output using ore types outside the design criteria. The structuring of the project systems and industrial relations policies contributed to construction being completed within time and under budget. The plant was built without any major industrial dispute occurring and no dispute arose due to the uranium issue.

Jan 1, 1983

By Larry Whittle

Gold milling activities generate waste streams containing dissolved metals and cyanide, among other contaminants, that require some form of treatment prior to discharging to the environment. To date, this treatment has involved the destruction of cyanide through natural degradation, chemical oxidation, or a combination of both followed by the precipitation of metal hydroxides. Although these processes have been proven to be capable of achieving. regulatory levels for metals and cyanide, they often generate significant levels of cyanate and, at times, ammonia, that may be toxic to rainbow trout and thus undesirable for regulatory compliance. Tallon Metal Technologies Inc. (Tallon) has developed Vitrokele™, a chelating resin that has the ability to capture metals (including gold), both total and weak acid dissociable cyanide, as well as thiocyanate from both slurries and solutions. The loaded resin is eluted and returned to the recovery circuit while metals and cyanide are recovered from the eluent stream. This process was demonstrated at pilot scale at B.P. Resources' Hope Brook Gold Mine in Newfoundland, and more recently at Canamax's Bell Creek Mine near Timmins, Ontario. The results from these pilot programs showed metal and cyanide recoveries of 99% or more with the concentration of cyanide and metals in the effluent reduced to levels with minimal or no toxicity to rainbow trout. Furthermore, neither cyanate nor ammonia were generated from the process. The loaded resin was effectively stripped and re-introduced to the recovery circuit; cyanide was captured in the eluent stream and made available for recycling to the mill leaching circuit; and metals were captured for re-use, sale or disposal. This paper summarizes the results obtained from the pilot tests at the Bell Creek and Hope Brook Gold mine sites.

Jan 1, 1992

By E. O. Mixon, Jack D. Kennedy

INTRODUCTION This contract is the most northerly portion of the Metropolitan Sanitary District of Greater Chicago's Tunnel and Reservoir Plan. (TARP) The project begins at Addison Street in Chicago and proceeds northerly approximately ten miles to end at Wilmette Harbor and Lake Michigan. The project which consists of 2 work shafts, 32 drop shafts, 7.322 km (24,020 ft.) of 6.7 m (22 ft.) diameter circular rock tunnel, 8.458 km (27,750 ft.) of 9.2 m (30 ft.) diameter circular rock tunnel and miscellaneous rock bolting and grouting, was bid for a total cost of $63,140,480. The tunnel invert elevation varies from 65.5 m (215 ft.) to 77.4 m (254 ft.) below the ground surface, which places the tunnel in a rock formation of dolomite limestone. At the tunnel invert, the unconfined compressive strength of the limestone varies from 96 MPa (14,000 psi) to 152 MPa (22,000 psi). The 6.7 (22 ft.) diameter tunnel required the mining of 10.9 cu m. (14.2 cu yd.) of rock per lineal foot of tunnel while the 9.2 m (30 ft.) diameter tunnel required the mining of 20.1 cu m (26.3 cu yd.) of rock per lineal foot of tunnel. The total cubic meters of rock required to be excavated from both tunnels was 818,821 cu m (1,070,978 cu yd.). All of this will be mined by tunnel boring machines (TBM). These tunnels were not to be lined with concrete. The thirty two drop shafts have upper portions that are cylindrical in the overburden and rock sections. They were divided into two groups, depending on diameter, with a different construction method for each group. The first group consisted of twenty three of the

Jan 1, 1979

By Noah Fields Drake

During July and August, 1899, the writer took advantage of an opportunity of going to Shansi to gather some information concerning the geology and value of the already famous coalfields of that province. The long journey, mainly on slow river-boats, and the limited time at command, allowed only about ten days of work to be done in the coal-fields around Tsê Chou. The geologic structure and the rock-formations were found to be simple and quite regular, so that in that time the accompanying sketch-map (Pig. 1) was made, and a fairly good idea of the distribution of the coal and general geologic features was obtained. The map was made by measuring a base-line about three-quarters of a mile long, triangulating for principal points over the field, and filling in the details by rapid sketches. The few elevations marked on the map were taken with an aneroid barometer. Only a few of the great number of towns and villages that are within this densely populated area are shown; and the coal-mines indicated are not the only ones within the area, but the ones where most of the following information about the coal was obtained. The value of this coal-field was first clearly set before the scientific and commercial world by Baron von Richthofen,* who made a geologic reconnaissance of Shansi in 1870. Since that time the hostile attitude of the Chinese government and people towards foreigners and their enterprises has kept the coal-fields from being developed. But the last few years of rapid change in the conditions of China have at last apparently opened a way for the exploitation of this coal-field. The Peking syndicate, a joint English-Italian company, now has concessions from

Jan 1, 1901

By Alexander Pomerantsev

In recent years, bucketwheel excavators have found wide application in open pit surface mining not only because of their large production capacities, but also because they easily lend themselves to automation. Krupp, Orenstein & Koppel, Buckau-Wolf, Mechanical Excavator, Lauchhammer, Manufacturers in Eastern Europe designed and installed many models of bucketwheel excavators that can excavate any type of materials, could be used in any climate conditions and for any type of technological schemes in open pit surface mining, (Photo I, II and III)

Jan 1, 1979

By Larry Ng, Keith McDonald

The benefits of controlled blasting techniques have gained increasing recognition by the mining industry in recent years. The utilization of an effective controlled blasting programme can result in a safe work environment with less loose rock and a reduced level of scaling and ground support.

Jan 1, 1994

By R. A. Pasternak, B. Evans

In an ultrahigh-vacuum study of the sorption of nitrogen by niobium* resistivity data for this metal have been obtained as function of temperature and of low nitrogen concentrations. The ultrahigh-vacuum system in which base pressures of about 5 x l0-10

Jan 1, 1965

By B. J. Arnold, B. W. Parker

Rosebud Mining Company added a classifying cyclone/spiral concentrator circuit addition to its McVille Preparation Plant, Freeport, PA, in mid-2002. This paper will describe the plant addition, which was implemented fully by plant staff, and review improvements in cleaning plant performance and economics.

Jan 1, 2003