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By Sam H. Patterson

Australia has led the world in bauxite production since 1976, and only the Republic of Guinea has larger bauxite resources. India has a small integrated aluminum industry, and deposits containing more than 1 Gt (billion metric tons) of bauxite were discovered in the 1970's. The Peoples Republic of China has large bauxite resources scattered in several regions, but it is a monohydrate type that is difficult to process for aluminum. Indonesia and Malaysia both have long histories of bauxite mining, and both have limited resources of high-grade bauxite. Districts containing bauxite resources in the 10 Mt to 150 Mt (million metric tons) range are scattered in countries along the eastern rim of the Pacific Ocean, on islands in this ocean, and on the western and northern rims of the Indian Ocean.

Jan 1, 1982

By J. Geisler

When addressing Germany’s resource supplies, we need to distinguish between those domestically available and imported ones. Resource extraction ostensibly competes with the designation of protection areas. However, the parallel existence of wildlife and plant life, and operations in the areas used for resource extractions is continually underestimated. The European Commission has compiled guidance documents facilitating the extraction of resources from protected areas. With regard to resource productivity, the market appears to be the appropriate instrument for minimising resource consumption. Policy makers are now called upon to create a legal framework leading to a consensus accepted by society.

Jan 1, 2011

By W. E. Wallace, P. S. Raghootama, M. S. Seehra, C. A. Hill, M. J. Keane, P. Mike

"Dipalmitoyl glycerophosphorylcholine (lecithin) dispersed in physiologic saline, a model of the primary component of pulmonary surfactant, is adsorbed by respirable quartz and aluminosilicate dusts. Dust cytotoxicity as measured by erythrocyte hemolysis and pulmonary macrophage enzyme release is suppressed by this adsorption. The degree of suppression of hemolytic potential versus specific adsorption of lecithin from dispersion in saline by respirable quartz, kaolin, and alumina dusts are compared with dusts' BET specific surface areas to interpret the prophylactic effect cf lecithin adsorption. Dust hemolytic potential versus media pH are presented. Fourier transform infrared spectroscopy and photoacoustic spectroscopy of lecithin on quartz and of lecithin on kaolin are presented and reviewed with results of studies of the time course of removal of lecithin adsorbed on mineral surfaces by digestion by phospholipase enzyme. Results are discussed in terms of a model of prompt neutralization of respired mineral dusts by pulmonary surfactant, and a gradual re-toxification by digestive processes acting on the adsorbed prophylactic surfactant coating following phagocytosis.Introduction Quarts dust of respirable size is well known to cause fibrotic lung disease, but numerous questions persist in the understanding of the initiation and' progression of this disease. Our approach concentrates on physical and chemical aspects of mineral dusts early-on in their interactions with living organisms, and we have chosen simplified models to investigate that interaction. In the alveolar spaces of the lung, tissue is coated with a surface-active material (pulmonary surfactant), which, sagas other functions, mechanically stabilises the lung from collapse by reducing the surface tension of water in the alveolar sacs.(1) This surfactant is also the material that is first contacted by a mineral particle that is transported to an alveolus and is impacted there. This surfactant material has been studied extensively. The primary components are known to be proteins (about 11% in dog lavage fluid). and phospholipids (about 88%).(2) Fhosphatidyl cholines constitute roughly 80% of the phospholipid fraction; about 70% of the phosphatidyl choline fraction is dipalaitoyl lecithin (DPL).(2) Respirable aluminosilicate particles are capable of adsorbing dipalmitoyl lecithin from dispersion in physiologic saline, a model for a possible initial event occuring upon deposition of a particle in a pulmonary alveolus.(3)"

Jan 1, 1988

By M. Fiset, D. Belley

"To better understand the wear process of various materials that may be used as blades on snow removal equipment, the first step is to evaluate the influence of the load applied and the moving speed on road wear rates of one type of steel and three types of polymers. While the behavior of steel conforms to Archard's law, wear rates of polymers increase to a power of ex of the load applied according to a model implying that the wear of these materials is due to fatigue. The wear rate of some of the polymers varies considerably in terms of speed, unlike the steel. The wear resistance of some of these polymers outclasses the steel tested as long as the speed is not too great. They, therefore, present interesting alternatives for snow removal on more fragile surfaces such as sidewalks and zone made of inter-block slabs.IntroductionSince the dawn of the Industrial Revolution, the massive use of machines has brought with it a number of different problems regarding wear. Snowplowing roads, parking lots and sidewalks is an activity that generates enormous expense in a country such as Canada. To better understand these wear processes and in the hope of stimulating new approaches designed to reduce the costs related to this sector of activity, this paper presents the behaviour of several materials (steel, polymer and rubber) as they wear on an asphalt-fines matrix surface lubricated with water. Also discussed is the effect of various parameters such as the load applied and speed."

Jan 1, 1990

By K. A. Natarajan

Interaction with microorganisms results in significant surface chemical changes on minerals. For example, chemolithotrophs such as Thiobacillus ferrooxidans and Thiobacillus thiooxidans significantly alter the surface chemistry of several sulfide minerals such as pyrite, chalcopyrite, sphalerite and galena. Heterotrophic bacteria such as Bacillus sp. could alter the electrokinetic properties of oxide minerals such as hematite, alumina, silica, kaolinite and calcite. Microbe-mineral interactions could thus be beneficially utilised in mineral beneficiation as different from bioleaching. Microbially induced mineral beneficiation unlike bioleaching deals with interfacial phenomena at mineral-solution-bacteria interfaces and surface chemical changes are brought about at very rapid rates amounting to a few minutes resulting in mineral separations in an aqueous medium.

Jan 1, 2003

By H. J. Sloman

Mining laws of the several coal-producing Stat e with respect to safety catches on mine cages and their testing are extremely variable and generally indefinite in scope. The most specific requirements are contained in the Coal Mining Laws of Washington,3/ as follows:

Jan 1, 1944

By J. H. Bassarear, P. F. Thomas

Large-scale equipment can reduce both capital and operating costs for concentrators. Large semiautogemus (SAG) mills can be effectively utilized in big mills but they must be kept fully loaded to tab advantage of their great potential. With varying hardness ores, controlling throughput is difficult and careful design must take this into consideration. A variable speed drive on large primary semiautogemus mills can overcome this problem to a considerable degree. This paper provides a base case using standard accepted technology of two wound rotor single speed 4476 kW (6000 hp) motors to drive the primary SAG mills of a hypothetical 36,364 t/d (40,000 stpd) typical porphyry copper mill. One other fixed speed drive will be described and jive variable speed drive configurations will be reviewed. Capital costs for the entire grinding circuit, from crusher product to flotation feed, were developed for the base case and each of the alternatives. A technical evaluation comparing the advantages and disadvantages of each drive is presented.

Jan 1, 1987

By D. William Tedder

Several bauxite residue sands and muds produced by Bayer plants in the U.S. and overseas have been fractionated using dry and wet magnetic separators. The magnetic sand fractions typically contain about 60 wt% iron and the bulk of the radioactivity in this waste. The muds are more difficult to process than the sands, but some fractionation is possible using a combination of flotation and magnetic separation techniques.

Jan 1, 1984

By Ramkrishna Agarwal

The problem of the measurement of in situ stresses in rock masses has, in recent years, become one of the prime concerns of investigators and researchers in the field of rock mechanics. Numerous instruments have been developed for that purpose and various techniques have been used to determine the absolute values of these stresses at a point.l The "stress-relief" technique has gained the widest acceptance. In its usual application it relies on one of the two following principles: (1) Measurements of the changes in a "solid inclusion" in a borehole,2 or (2) Measurements of the diametral deformation of a borehole with a free boundary." The theoretical development, in the case of the latter, is based upon an evaluation of the deformation of a circular hole in an infinite plate under the action of a uniaxial stress field. Expressions for the deformations may be obtained by using either the plain strain or the generalized plane stress theoretical approach of the classical theory of Elasticity, which assumes that the material is linearly elastic, homogeneous and isotropic. The solution for the case of a biaxial stress field is obtained by the Principal of Superposition. The circular hole becomes elliptical after deformation takes place under the action of a uniaxial or biaxial stress field applied to the plate. In the practical application of the technique, the reverse procedure is applied. A borehole is drilled in the rock and a deformation-measuring

Jan 1, 1968

By Paulo Couciero

Since explosives are the source of all energy used for rock blast fragmentation and heave, multidimensional effects in the detonation driving zone become essential to better describe the detonation process. In order to use the explosive as an energy source-information for more realist blasting performance simulations, a simple and effective modelling strategy is desirable. Facing this challenge, an engineering approach to two-dimensional unconfined non-ideal detonation is proposed. Based on the elliptical construction of the shock locus, the model combines the axial cylindrical stick Q1D solution with some additional limiting conditions to determine the sonic edge of the charge. For a given set of rate law parameters and velocity of detonation, a complete axial solution is firstly computed through the Q1D model. From this solution, a vital relationship between the axial shock curvature with the shock shape parameters can be stablished. Once this relationship is found, the problem simply reduces in finding the shock shape parameters subject to the sonic edge condition. As a result of this calculation, the corresponding charge diameter can be found. Consequently, the proposed model can map the diametereffect curve by relating the unconfined velocity of detonation with its corresponding diameter. Finally, because of its low computation cost, the proposed engineering approach can be also used for characterizing the rate law parameters by fitting to data from unconfined detonation experiments

Jan 1, 2019

By A. W. Jolliffee

ANY attempt to forecast the mineral resources of a largely unknown region is hazardous and, in the case of the Northwest Territories, such a task is even more hazardous than usual. This is not merely because of the immense territory involved (over a million and a quarter square miles), only a small fraction of which has ever been explored or prospected, but also be-cause both the geology and mineral deposits thus far examined show many unique features, and, finally, because the region is being actively prospected at the present time. However, in view of the present widespread interest in Canada's mineral resources, a brief compilation of what is known regarding mineral occurrences and geology in the explored parts of the far north seems timely. From these assembled data, a few inferences are warranted as to future mineral production from this region. HISTORY The story of mineral discovery in the Canadian northwest is a fascinating one. As well, it abundantly illustrates the importance of mineral occurrences in indicating future mining possibilities. The same sequence of events has repeated itself too often to be merely fortuitous.? In most cases, the dis-covery of a mineral deposit of possible economic value has been foreshadowed by the finding of the valuable mineral or an associated mineral in the same district, generally in small quantity, by an early explorer or traveller. Thus, John Franklin reported oil seepages from the base of Bear Rock, near Nor-man, at almost the very spot where oil was struck nearly one hundred years later. Again, some would-be Klondikers, deterred by the hardships of the route, remained to prospect around Great Slave lake, and were the first to report the Pine Point lead-zinc occurrences there and the gold-bearing veins on Yellowknife bay. Sporadic prospecting followed at the latter locality for over thirty years before the recent rich strikes were made. Similarly, in 1847, Dr. John Rae picked up a boulder of copper ore south of Rankin inlet, on Hudson bay. More than eighty years later, a body of copper-nickel sulphides carrying values in platinum metals was found at this locality. Also, the report of cobalt bloom on the east coast of Great Bear lake brought back by a Geological Survey of Canada party in 1900 was a factor in the events leading to the discovery of silver and radium there in 1930.

Jan 1, 1937

By C. R. Hopkins

"The petroleum refiners of the United States made rapid strides in fuel economy in 1928, when the calculated number of B. t. u. required to refine a barrel of crude petroleum was 637,000 as compared with 698,000 in 1927, a decline of 9 per cent. The major portion of this indicated increase in fuel efficiency was undoubtedly due to the gain in use of the pipe-still and the continuous process of refining as contrasted with the old batch method of distillation.,Almost without exception the new refineries are equipped with one or more pipe-stills, and many of the older plants are changing over to this type of equipment. The refineries of the Appalachian area are among the oldest and most conservative of the country, yet a number of them dismantled their old shell and cheese-box stills and installed pipe-stills in 1928.The more extensive use of the pipe-still was not the only way in which the refiners lowered their fuel requirements in 1928. The use of heat-exchangers, in which the heat from hot vapors to be condensed is used to heat the incoming cold oil, also increased in 1928, and in addition the refiners have kept abreast of the times in saving fuel through better insulation and improved burners.For the year 1928 the refiners burned as fuel the following: 46,400,000 barrels of-fuel oil; 3.362,000 short tons of coal; 114,950,000,000 cubic feet of natural gas; 77,313, 000,000 cubic feet of refinery or still gases; and 470,000 short tons of coke, in addition to a little electricity. This fuel was calculated to have produced a grand total of 582,156 billions of B. t. u., as compared with 578,784 billions B. t. u. in 1927.The total of 46,400,000 barrels of fuel oil burned represents an increase over 1927 of about 5,000,000 barrels, which made it about equal to the 1926 figure. Practically all of the refinery districts used more oil as fuel in 1928. The most important increase - over 2,000,000 barrels - occurred in the East Coast district, where greatly expanded throughput of foreign crude was instrumental in increasing fuel-oil production.The use of coal for fuel at refineries again registered a material decline, the total for 1928 of 3,362,000 short tons being 33 per cent below that of the previous year. The outstanding decrease in the use of coal in 1928 occurred in the East Coast district, where coal was probably replaced by oil. The use of coal for fuel at refineries in the States of Ohio, Pennsylvania, and West Virginia declined materially in 1928; the substitute used in the majority of cases was oil burned in pipe-stills."

Nov 1, 1929

By Butt C. R M

Resurgence in Au exploration during the past decade has been characterised by a considerable emphasis and dependence on geochemical procedures. This has been made possible, firstly, by marked improvements in analytical sensitivity over those previously available and secondly, of particular importance to exploration in Australia, by a better understanding of the distribution of Au in the regolith, which has led to the optimisation of sample media. These developments have given exploration companies the ability to seek and detect subtle and widespread geochemical signatures of concealed Au mineralisation and provided an enhanced capability to interpret the data. As a consequence, several new discoveries have been made, even in areas that have been intensively explored in the past. In the deeply weathered Yilgarn Craton (WA), and in equivalent areas elsewhere in Australia and overseas, Au has accumulated in the upper lateritic gravels and duricrusts of the regolith, probably during humid climatic periods in the Tertiary. The laterites may not only be Au ores in themselves, but research by CSIRO and CRC LEME has shown them to be very important sample media, (eg Anand and Smith, 1992). In many areas, however, the laterite has been eroded and hence is unavailable as a sample medium and chemical modification under more and conditions since the Tertiary has leached Au from the upper saprolite. This has greatly increased the difficulties of exploration, particularly where reliance was placed on sampling between 2 and 15 m of the surface. Further research, however, has demonstrated that, despite this leaching, recent remobilisation of An has caused it to concentrate in a specific soil component, pedogenic carbonate, usually in the top I - 2 m, thereby giving surface expression even to mineralisation that is concealed by over 20 in of leached overburden. Secondary carbonates, commonly referred to as calcrete, may precipitate as calcite and/or dolomite in regoliths where the average annual rainfall is less than about 600 mm. Pedogenic carbonates are those that form in unsaturated (vadose) soil horizons. They are widely distributed in the Gawler and Yilgarn Cratons. In the Yilgarn Craton south of about 30¦S ('the Menzies Line'), they are seemingly more abundant over more basic rocks and towards the south east (Figure 1). In contrast, groundwater calcretes form in saturated (phreatic) environments, typically in the axes of major drainages north of the Menzies Line. These are known to accumulate economically-significant grades of U but not, apparently, An.

Jan 1, 1997

Two coal seams were selected and the conceptual designs were based on the geological and physical conditions typical of these seams. As a result of the screening process presented below, the two coal seams selected were the Lower Kittanning Seam in central Cambria County, Pennsylvania and the Pittsburgh Seam in northwestern West Virginia and southwestern Pennsylvania. SELECTION PROCESS FIRST SCREENING OF LONGWALL OPERATIONS The list of longwall operations prepared in Phase I and included in the Phase I report, was used as the basis for a first screening. From this list it was determined which longwall operations were not in the Appalachian coal fields and not in a coal seam of the thickness range of 42 to 72 inches. The first screening eliminated 30 of the listed operations, leaving 48.

Jan 1, 1976

By Wencheng Gao

An attractive way to beneficiate magnesium chloride and aluminum chloride is to prepare Mg-Al spinel, an excellent refractory material. Mg4Al2(OH)14?3H2O, the precursor of spinel, can be prepared using a co-precipitate method from aqueous MgCl2-AlCl3 solutions. The co-precipitation process of magnesium-aluminum from acidified chloride solutions by using NaOH or NH4OH as base neutralization agent was studied. Co-precipitation was conducted from different mixed solutions ? at initial CAl=0.0625M and Mg/Al molar ratio from 0.5 to 10, the temperature range from 30 to 90 °C. The effect of other parameters, including base type, method of base addition, base addition rate, aging time, background electrolyte and concentration were also investigated. The co-precipitation process was monitored by potentionmetric(pH) measurements. The experimental pH curves were characterized by two platforms separated by a steep jump in pH at Mg/Al molar ratio 0.5~6. The first platform was centered at about a pH of 3.8 and the pH of second platform was varied with different conditions. When the Mg/Al molar ratio was up to 6~10, the first platform in pH was almost disappeared. Furthermore, the shapes of pH curves were also affected by base type, base addition rate and method of base addition. Experimental results showed that the first platform in pH was connected with Al precipitation, and the second platform was involved with Mg. The final co-precipitates were characterized by XRD, TGA-DTA, particle size analysis, SEM and TEM. We found both Mg/Al molar ratio and temperature proved to be the key parameters controlling the formation of Mg4Al2(OH)14?3H2O phase. At solution Mg/Al ratio=0.5~4, the main precipitate phase was Bayerite (Al(OH)3) admixed with Mg4Al2(OH)14?3H2O; at Mg/Al ratio=4~6, the main phase was Mg4Al2(OH)14?3H2O admixed with some Mg(OH)2; while from Mg/Al ratio=6~10, the systems were mixtures of Mg(OH)2 and Mg4Al2(OH)14?3H2O.

Oct 1, 2011

By B. S. Terry, C. L. Harris

Reduction kinetics from slags containing CuO(0.5), ZnO, PbO, NiO and SnO into a Cu-based metal phase were subjected to computer simulation using a previously developed model for the kinetics of metal-slag-gas reactions that assumes mass-transfer control in all phases. The effects were examined of changing bulk Fe oxide activity, gas reducing potential, temperature, Fe content of the Cu phase and metal/slag ratio. The results permit practical conclusions to be drawn about industrial slag-cleaning practice, but the model is still limited in terms of thermodynamic inputs and the idealisation of reaction conditions

Aug 1, 1995

By L. P. Bayvel

The method of spectral transparency was investigated. A device for measuring particle sizes based on this method was developed, tested and applied. The device affords measurements of particle size distribution in the range from 0.1 to 4 µm. It proved possible to measure sizes not only of spherical particles but also of non- spherical ones. The spectral range in which it is necessary to determine transparency for particle size measurements was found.

Jan 1, 1980

By Kenneth W. Luke

In the development of the ultimate pit limits for a narrow ore body, pa¬rameters necessary in the design of a functional, or working, pit become highly sensitive factors in the determination of ore reserve levels and their associated waste to ore stripping ratios. Through the use of geologic cross sections, ore reserves can be roughly calculated by utilizing a straight line approximation for pit wall slopes. The optimum position of the pit floor can be substantially altered from such a preliminary design though with the introduction of functional mining parameters, such as a ramping network, and working bench heights, berm widths, and bench to bench wall angles. Originally a computer program was developed to quickly evaluate changes in cross-section pit design with minimal alteration of input data. After developing a satisfactory technique of cross-section evaluation which incorporates working mine parameters, an optimization algorithm, or procedure, was developed and included in the program to eliminate much of the tedious manual decision-making required in determining the optimum location of the pit floor on each cross section. Optimization in this case implies the maximum profit pit. When pit and processing costs are defined or hypothesized, this computer program can be used to design the maximum profit pit, constrained by the recognized functional mining parameters. A second way of stating the optimization is that the program can be used to develop a pit design which minimizes waste stripping at any desired ore reserve level. The basic method of cross-section evaluation parallels present manual methods. Program input is a combination of data obtained directly from cross sections developed for, geological interpretation and pit design parameters selected by the mine planner. As a result it is easy for the mine planner to comprehend what the program is accomplishing, and thus participate in the development of the computer assisted design.

Jan 1, 1971

By Luan Monteiro, Francisco Biulchi

The AngloGold Ashanti - Cuiaba mine sought innovative approaches to minimize lateral development and stope extraction time while maintaining optimal gold recovery and minimizing dilution. The stope 8GAL EXT 30 was selected as a case study. Traditionally, conventional blasting methods in such a scenario would necessitate either a single mass blast or slot development at each end of the stope. These methods typically compromise recovery and dilution or increase development time and risk. Additionally, conventional wired detonators require workers to re-enter the stope between blasts to load blastholes and connect detonators. The wireless initiation system offers a solution by initiating blastholes using magnetic induction signals that can penetrate rock, air, and water. This technology allows a pre-charged stope to be mined without requiring workers to re-enter the area between blasts to charge and connect blastholes. Engineers from Orica and AngloGold Ashanti designed a new extraction sequence utilizing the wireless initiation system. The process began with the opening of one end of the stope using a conventional slot and wired electronic detonators. Subsequently, pre-loaded rings were fired in three blasts to extract the opposite end and the intersection. The 8GAL EXT 30 stope was successfully mined using this technology enabled method. Each blast was meticulously monitored, and the stope void was scanned to assess blast performance. The results demonstrated a 4.6% improvement in recovery and a 16% reduction in dilution compared to the initial plan, and reduced exposure of people to hazardous locations in the stope. These results represent an additional value of USD 200k, gained from implementing wireless initiation to enable this particular blasting schedule.

Jan 21, 2025

By Donald H. Matthews

The Society of Explosives Engineers is an international organization of over four hundred members involved in the explosives industry, with most members being active in the United States. The regulations imposed by regulatory agencies on the explosives industry have drastic effects far beyond the industry. Since explosives are used in mining, manufacturing, construction, entertainment, and art, all phases of man's activities, including fundamental needs for survival, are affected by how efficient the industry uses explosives. We, as members of SEE, must be sincerely concerned with both the quantity and quality of government regulation, and this paper spells out some of the problems caused by regulations and offers a solution.

Jan 1, 1980