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By V. A. Melezhik, P. K. Skufin, L. P. Nilsson

these factors into account. Theoretical and

Aug 1, 1994

By John H. Bassarear

The never ending search for lower unit costs led Pima Mining Company's management to study various alternatives shortly after Expansion III was completed. It soon became apparent that a considerable amount of ore assaying 0.35% copper had to be moved in order to maintain mill feed at the desired 0.54% copper content, which is the overall grade of the ore reserves. Detailed investigations revealed that for a period of 8 - 10 years, about 14,000 tons per day of 0.30 - 0.40% copper ore would pass by the crusher en-route to the low grade stockpile. This ore is very hard, very clean and has to be mined at a relatively uniform rate. A six month pilot plant run testing autogenous and semi-autogenous grinding gave very encouraging results. Since no mining costs need to be charged to the extra tonnage (it had to be mined anyway) the only major costs would be against milling. The decision to proceed was made in August 1970 and Fluor-Utah was retained as the prime design construction contractor. Ore was first put through the new mill on December 29, 1971. By March of 1972 design tonnage of 14,000 TPD had been attained. The first three expansions at Pima Mining Company, 20 miles south of Tucson, increased mill capacity from 3,000 TPD to 36,000 TPD. These expansions included a separate, conventional, three stage crushing plant plus additions to the existing concentrator that primarily duplicated the then current flowsheet. Expansion IV, however, consisted of an entirely new and separate primary crusher and a completely new mill building located about 2,000 feet southeast of the 01 d concentrator. The new mill, using semi-autogenous grinding, produces scavenger and rougher flotation concentrates that are pumped to the old mill for regrinding, cleaning, thickening and filtration.

Jan 1, 1973

By S. Ralph Austin

Emanation coefficients of 950 samples of domestic uranium ore were successfully and rapidly determined with fair precision by modifications of the closed-can, gamma-only assay method, using commercially available or similar equipment. Coefficients range from <1 to 91 percent. Emanation varies considerably within each mine and area, but distinct differences among major mining areas were found, ranging from 7.5 percent for Moss Back Member, Chinle Formation, Southwest Lisbon Valley, Utah, to 56.6 percent for Ft. Union Formation (?), Powder River Basin, Wyoming. Coefficients also vary with (1) uranium mineralogy; (2) radium mineralogy; (3) lithology of host rocks; (4) grain size of uranium and radium minerals; (5) comminution of ore; (6) estimated porosity and permeability; (7) moisture content; (8) ore grade; (9) supposed mobility of deposits; age of deposits is unknown but limited by (10) age of host rocks which shows only doubtful correlation with emanation. Data obtained may be used to evaluate effects of investigated parameters on radon concentration in mines and thus to select efficient control measures. Drill-core emanation data allow estimates of probable radon problems in undeveloped deposits.

Jan 1, 1978

By K. H. Coats, M. H. Terhune

Analysis and example applications have been performed to compare the accuracy and computing speed of alternating-direction explicit and implicit procedures (ADEP and ADIP) in numerical solution of reservoir fluid flow problems. ADIP yields significantly greater accuracy and requires about 60 per cent more computing time than ADEP, not 300 or 500 per cent more as reported elsewhere. l,2 INTRODUCTION Several recent papers 1-3 discuss an alternating-direction explicit difference approximation (ADEP) to the diffusion equation. Example applications of ADEP and ADIP4 were reported to support conclusions that ADEP is comparable in accuracy to ADIP and requires one-fifth to one-third the computing time of ADIP. Applications of ADEP in calculation of two-phase flow in reservoirs was also proposed. 3 This study was performed to compare further the relative merits of ADEP and ADIP in simulation of two-dimensional flow of one and two fluid phases in reservoirs. Since two-phase flow equations are often essentially elliptic rather than parabolic, the efficiency of ADEP in solving the elliptic equation was also examined.

Jan 1, 1967

By Garnsey R. G T, Wenk G. J, Toop A, Sowerby B. D

A bulk mineral analyser (BMA) suitable for the determination of Cu or Ni in bulk ore samples has been developed at the Lucas Heights Research Laboratories. This analyser, which uses the nuclear resonance scattering technique, is highly specific to the wanted element. The technique has previously been extensively field tested for copper at Mount Isa, Queensland.The present paper discusses the field trial in 1982 of a commercial prototype BMA for nickel. The trial was undertaken at the lateritic nickel mine at Greenvale, Queensland. The BMA and its shielding, together with a laboratory spectrum analyser, were sited in the sample shed adjacent to the workings. Two hundred and thirty-eight ore samples taken directly from the mine blastholes were assayed by the BMA. The average mass of sample was 12 kg, metal contents varied from 0.2 to 3.5 wt/per cent Ni and 4 to 43 wt/per cent Fe and free moisture varied from 11 to 55 wt/per cent. A measurement took 10 min to complete, although this time could have been reduced at the higher nickel grades. The r.m.s. deviation between BMA and chemical assays was 0.09 wt/per cent nickel. Iron and bulk density were also determined by the BMA, r.m.s. deviations being 1.7 wt/per cent and 0.03 g/cmJ respectively. Similar results could be expected from a BMA in routine industrial use at other nickel mines.

Jan 1, 1983

By R. F. Zaffarano

Intergrated energy balances and energy flows were constructed and quantified for State, regional, and national levels from four separate supply and demand commodity balances for coal, dry natural gas, petroleum and natural gas liquids, and utility electricity. These commodity balances were integrated by source and sectors through conversion and aggregation of their components to energy equivalents expressed in British thermal units (Btu). A summarization of the total gross energy components of supply and demand for commercial energy derived from direct fuels, hydropower and nuclear power, based on individual States and regions, is tabulated for 1960 and 1965. Pertinent computerization details and more than 500 individual State and regional printout tables, in both original commodity units and Btu&apos;s, are shown. Using these data, energy flows between States and regions were calculated to identify surplus and deficit energy areas. Report emphasis is on the conceptual aspects of integrated energy balances, rather than on the development of missing State energy data.

Jan 1, 1969

By T. A. Rundle, K. Kim, W. M. McCabe, E. C. Gregory

Overcoring tests were conducted at the Near-Surface Test Facility(NSTF) to assess the suitability of five techniques (U.S. Bureau of Mines borehole deformation gauge (BDG), Commonwealth Scientific and Industrial Research Organization (CSIRO) hollow inclusion stress cell, Luleå triaxial gauge (LuH gauge), and Council for Scientific and Industrial Research (CSIR) doorstopper) for in situ stress determination in a closely jointed basalt. This effort is in support of the Basalt Waste Isolation Project, which is studying the feasibility of locating a nuclear waste repository in the basalts of the Hanford Site in southeastern Washington. This paper presents the results from the overcoring study that formed the basis for selection of two techniques to be used during the further exploration of the basalt formations at depth.

Jan 1, 1983

By Misra V. N

Davis tube tests were conducted on a Koolanooka magnetite iron ore sample, supplied by Kingstream Steel Ltd, to determine the optimum grind size, maximum iron recovery and the cleanness of the products from low intensity magnetic separation (LIMS). The ore sample contained 38.6 per cent iron, 37.8 per cent silica, 6.5 per cent magnesia and 0.54 per cent alumina. XRD and microscopic examination showed that the main minerals in the ore were amphibole (42 per cent), magnetite (39 per cent), and quartz (14 per cent). Amphibole, (Mg, Ca, Fe),Si8O22.2(OH), containing 50.3 per cent SiO2, 35 per cent FeO and 11.5 per cent MgO is the main gangue mineral in the ore, and about 30 per cent of the total iron in the ore is contained in the amphibole. Heavy liquid separation tests showed that it is very difficult to separate iron from silica by gravity separation to obtain a high quality iron concentrate. Three grind sizes were initially tested, ie 45, 38 and 20 ¦m. It was found that grinding to 100 per cent -38 ¦m (P80 of 29 ¦m) appeared to be the best option for liberating the magnetite from gangue minerals. The iron recovery to the LIMS magnetic product for the 100 per cent -38 ¦m sample reached 73 per cent and the iron content was 65 per cent. Further test work suggested that the optimum grind size was a Psu of 25 ¦m.

Jan 1, 1999

The prevention of silicosis by metallic aluminium has been reported by Denny, Robson, and Irwin in two papers. The first was published in 1937; the second in 1939. The results definitely established that silicosis was prevented in animals by the inhalation of small quantities of aluminium. The present communication records subsequent progress in this field of research.HARMLESSNESS OF ALUMINIUMAnimal experiments having served their purpose, it became necessary to consider means to test the discovery on humans. A question for immediate consideration was: Is aluminium harmful to man when inhaled as a fine powder? While the animal experiments were reassuring, since they conclusively showed the powder to be innocuous when breathed by animals, it was, nevertheless, desirable to have additional reassurance with regard to its effect upon human beings.Through the courtesy of the Aluminium Company of America and especially the valued interest in this problem displayed by that Company&apos;s Director of Research, Dr. Francis C. Frary, a study was made of the records pertaining to the health of a group of 125 employees who had for many years been engaged in the manufacture of finely powdered, metallic aluminium for the paint and ink industries. The conditions were such that these employees had inhaled varying and oft-times very dense concentrations of this powder daily over periods ranging from 6 to 23 years, the average 101 the group being 12 years. X-ray pictures of their chests showed no abnormalities attributable to aluminium. Their general health seemed better than that of the 3,000 workers in other sections of the plant. In fact, the early films of three employees in this group of 125 showed shadows suggestive of minimal tuberculosis, which shadows were not discernible in films taken after considerable periods of exposure to aluminium powder.The harmlessness of aluminium was; by this study, reasonably well established at the outset, a finding subsequently verified by Ontario research on humans.PROPOSAL TO TREAT HUMAN SILICOSISBased upon these findings, a proposal to treat silicotics with aluminium was discussed by officials of the Mclntyre Mine and the Banting Institute.

Jan 1, 1945

By L.L. Wyman

The exact nature of the changes that take place in the iron-nickel alloys, giving rise to the interesting and useful expansion alloys in the Invar range, has yet to be fully understood. Similarly, the ternary iron-nickel-cobalt alloys, which also possess such commercially useful expansion characteristics,1,2 are concerned with transformations that appear to be identical with those found in the parent iron-nickel alloys. The investigations on iron-nickel alloys in the range 26 to 29 per cent Ni have been reported by several authors3-9 wherein it is shown that there are factors other than temperature, such as stress and grain size, which play an important part in determining the temperature at which the low-temperature transformation takes place. It will be shown in this paper that the ternary iron-nickcl-cobalt alloys having nickel contents comparable to the alloys mentioned above behave in a parallel manner. The alloys in the range of 26 to 31 per cent Ni and 16 to 21 per cent Co have a coefficient of expansion of about 4.0 X 10-6 per degree Centigrade, and the alloys in this range of composition find considerable application in making glass-to-metal seals, because these expansion properties so well match commercial glasses. The behavior of these alloys is not a simple matter, for it has been observed in alloys of 28.5 per cent Ni and 18.5 Co that severe working ran cause the appearance of a second phase having a needlelike structure similar to the martensite structure in carhon steels. Fig. 1 shows the change brought about in an alloy of this composition when a strip of this material was cut with tin shears. This second phase has been identified as the body-centered cubic alpha phase, and it is the purpose of this paper to describe the results of some of the preliminary investigations in the study of the changes involved in these alloys. Materials The past work on these alloys has concerned itself primarily with materials made by the usual casting procedure and involving the use

Jan 1, 1939

By L. L. Wyman

The exact nature of the changes that take place in the iron-nickel alloys, giving rise to the interesting and useful expansion alloys in the Invar range, has yet to be fully understood. Similarly, the ternary iron-nickel-cobalt alloys, which also possess such commercially useful expansion characteristics,1,2 are concerned with transformations that appear to be identical with those found in the parent iron-nickel alloys. The investigations on iron-nickel alloys in the range 26 to 29 per cent Ni have been reported by several authors3-9 wherein it is shown that there are factors other than temperature, such as stress and grain size, which play an important part in determining the temperature at which the low-temperature transformation takes place. It will be shown in this paper that the ternary iron-nickcl-cobalt alloys having nickel contents comparable to the alloys mentioned above behave in a parallel manner. The alloys in the range of 26 to 31 per cent Ni and 16 to 21 per cent Co have a coefficient of expansion of about 4.0 X 10-6 per degree Centigrade, and the alloys in this range of composition find considerable application in making glass-to-metal seals, because these expansion properties so well match commercial glasses. The behavior of these alloys is not a simple matter, for it has been observed in alloys of 28.5 per cent Ni and 18.5 Co that severe working ran cause the appearance of a second phase having a needlelike structure similar to the martensite structure in carhon steels. Fig. 1 shows the change brought about in an alloy of this composition when a strip of this material was cut with tin shears. This second phase has been identified as the body-centered cubic alpha phase, and it is the purpose of this paper to describe the results of some of the preliminary investigations in the study of the changes involved in these alloys. Materials The past work on these alloys has concerned itself primarily with materials made by the usual casting procedure and involving the use

Jan 1, 1939

By K. Bounou, K. Komnitsas

"Risk quantification may be used as a sustainable development index in the mining industry, since it encompasses both economic and social factors. In addition, it may assist in the development of a framework, which is also indirectly related to sustainable development, to prevent accidents and improve health and safety standards. However, risk quantification in the mineral sector involves diverse activities and is considered a very difficult task. Although statistical data report accident severity rates, incident rates and accident frequency rates, none of these allow for accurate risk calculations. In this paper, two risk calculation formulas, which may be used to quantify risk, as well as to identify hazardous activities in a workplace, are proposed. Numerical examples are given based on statistical data available through the MSHA database. Also a combination of a decision/fault/event tree that allows risk quantification is presented."

Jan 1, 2005

By E. D. Gardner

This paper is one of a series on milling methods being published by the United States Bureau of Mines. Atlanta is in Elmore County, Idaho, about 80 miles from the railroad at Mountain Home, Idaho. The concentrator is at an elevation of, 6,000 feet and located in a timbered, well-watered region of relatively heavy snowfall. The snow, however, does not seriously affect local operations. The track road to Mountain Home, which passes over a mountain range, is closed each winter from about November 1 to June 15. During this period concentrates are stored and bullion is shipped by airplane. Power is generated by a Diesel engine and by an auxiliary hydroelectric plant. Gold is the principal metal produced; the or also contains an able quantity of silver.

Jan 1, 1935

By C. C. Popoff

The growth of the aluminum-smelting industry in the Pacific Northwest, resulting from national defense requirements, emphasized a need for local sources of alumina to supplement the alumina production shipped from the East. Because supplies of foreign bauxite were being interrupted and our domestic bauxite reserves were inadequate, it was necessary to expedite the investigation of other possible sources of alumina during World War II. A program of investigation of high-alumina clay deposits in the Northwest was carried out jointly by the Federal Geological Survey and the Federal Bureau of Mines. As part of this program the Cowlitz clay deposits near Castle Rock, Wash., were explored by the Bureau of Mines in 1942-43. These deposits are near railroads, tide-water, and Bonneville Power Administration lines and within 22 to 100 miles of 4 aluminum-reduction plants.

Jan 1, 1955

By G J. A Dewar

The Australian Corporations Law generally requires Independent Expert Reports to be presented in support of capital raising or in defence of mergers and takeovers. The introduction of the VALMIN Code in 1995 (and its recent revision issued as the VALMIN Code, 1998) made Assessment and Valuation Reports in these circumstances much more comprehensible than before because of its key requirements for transparency and materiality. By forcing the Independent Valuer to provide an explanation of the reasoning behind the estimation of a particular resource asset, VALMIN allows the reader to clearly see any error or illogicality in the valuation methodology used and to seriously question or even reject the resulting value. Even though many elements of resource asset valuation practice are undeniably subjective, there must be some basis of objective rationality to it. Independent resource asset Valuers are the essential link between mineral explorers/miners on the one hand and brokers/analysts/fund managers/investors on the other. The minerals and financial industries both expect them to not use inappropriate or invalid valuation methods and illogical steps within these methods. This paper examines some of the less sensible ways in which some of the main techniques that Valuers commonly use to assess the fair market value of mineral properties have been applied in recent instances. The authors hope to discourage the adoption or perpetration of the æWhat-number-did-you-have-in-mind?&apos; approach. It is MINVALÆs view that as many methods as possible should be used in any resource asset valuation. If any of the resulting estimates are in approximate agreement (particularly if they were derived using the less subjective of the available methods), ie if they cluster, they are probably more persuasive as being the Preferred Value of the asset than outlier values within the Valuation Range.

Jan 1, 1999

Jan 1, 2001

Abrasivity and wear resistance are not intrinsic properties of materials, but rather parameters describing the interaction between the wear part and the material exerting the wearing action. Moreover, wear or, at least, that part of the wear which is due to the cumulative effect of minute scratches, is linked to the hardness disparity concept. Abrasivity, in this context, is a relative concept, pertaining to a metal-rock pair, rather than to a rock. Based on this assumption, a methodology has been developed and checked against actual cases, enabling description of the abrasiveness of arock or the abrasion resistance of a metal through the ratio of comparable quantitative indicators. The paper describes the methods and provides examples of applications to practical cases(namely: rock cutting, excavation by means of tunnel boring machines (TBMs), rock crushing, and hydro-mill cutting).

Jan 1, 2012

By J. P. Sancho, J. M. Duart, J. I. Verdeja, J. O. García

Following a short review of the history of rails used in the transport of passengers and goods, this paper describes the process for rail fabrication, rail structure, and properties, and summarizes the fatigue test curves carried out on rails used today. Also reported is the process for “continuous rail” production using aluminothermic welding via the introduction of weld metal in onsite casting, as a homogeneous melt. Weld characteristics of aluminothermic welding using different preheating procedures—fusion zone, heat-affected zone, microstructure, hardness, slow bend test, and fatigue test resistance (Wöhler curves)—are related to preheating and welding procedures of 700, 900, and 1,100 MPA rail grades. The Locati method is preferred over the staircase method for ascertaining the fatigue limit due to its simplicity. Macrographic and metallographic inspection of broken specimens reveals the reliability of welding techniques and the good metallurgical quality of welds.

Jan 1, 2007

By M. J. Beus, B. Stewart, S. Iverson

Ore-pass hazards are a significant safety problem in US underground metal mines. From 1975 to 1995, nearly 75% of injuries during pulling or freeing of ore-pass chutes were related to falls of broken rock or the use of hand tools. Risk assessment methods are being used to identify the most probable causes of ore-pass failures and analyse the factors that result in malfunctioning or safety reduction. Static and dynamic loads are being measured in the laboratory and by field testing, with data from test ore passes compared with mine data to characterise true system behaviour. Computer modelling using closed-form solutions, finite element analysis and a newly developed particle flow code are being use to predict loads from ore and waste flow and impact. Preliminary results indicate that dynamic impacts may be much less than expected, as a result of damping factors, normal and shear stiffness and mass frictional characteristics

Jun 19, 1905

By Sergey Ulianov, Arkady Senchenko, Alexey Shvets, Arkady Bakotin

"This paper contains description of research results of technology development for copper recovery from weathered tails of iron processing plant. The predominant host mineral that contains valuable component is chalcopyrite occurring in its free form and in associations with ore and rock-forming minerals. Copper grade is 0.26-0.30%. Emulsion inclusions of chalcopyrite in pyrite and sphalerite were noted. Major problem is low copper recovery (30-35%) by flotation. When studying chalcopyrite in primary concentrate it was determined that the surfaces of many chalcopyrite grains are covered with oxide films which prevented collector attachment onto them. Second issue was deep association of chalcopyrite with pyrite and sphalerite. Sulfidizing reagent addition did not help to reach the required level of copper recovery to concentrate. In the result of research performed the technological flowsheet was developed including preliminary treatment of head material in a special unit aiming at oxide films removal, followed by copper rougher flotation on head size tails, crude concentrate regrinding and a number of cleaner flotation operations. After the treatment of weathered tails according to the flowsheet developed, copper recovery to flotation concentrate became 71.53%, at 23.46% copper grade. The suggested technology allows one to solve the issue with treatment of technology-related copper-containing stockpile material, as well as to include the ores where copper is represented by sulfide minerals covered with oxide films into processing."

Jan 1, 2014