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By J. Visman

"SummaryThis paper is presented as part of a programme to show the steps taken by industry and others interested in supplying a solid fuel of constant quality to 'satisfy a consuming market. The paper deals with the general principles underlying quality control in coal preparation plants, namely, constant quality and close adherance to acceptance limits. It also describes how control of ash content is ""generally hampered by the problem of coal sampling .and the long duration of the ash analysis and how these difficulties may be overcome.Quality control can be effected in several ways. Thorough blending wll reduce variations appreciably, except those of long trend. The latter can be detected by automatic sampling and quick ash analysis. At present, under favourable conditions, a system of half-hourly ash determinations with an accuracy of 0.5 to 1.0 per cent can be realized, to the effect that trends with a 'wave length' of more than two hours cu be eliminated within the limits of accuracy of the ash figures. The general solution of the problem is a combination of blending, accurate sampling, quick ash determination, and statistical analysis of the pattern of ash distribution.The use of statistical methods of analysis, such as the t test and F test, is •discussed at some length in order to emphasize the importance of the correct evaluation of observational data if there is to be confidence in the validity of test results.General ConsiderationsCOAL, as a fuel, is too cheap for a long haul across the country. The limiting distance depends on the price of the local competitive fuels, and, as the price depends to a great extent on quality, so does quality, to the same extent, command the market."

Jan 1, 1952

By M. J. Hannan

Considerable interest has arisen in developing analytical methods suitable for measuring resource commodity substitution patterns. some of this work has applied the Translog method to estimate actual elasticities of substitution. Recent examples incl.uae Privolos and Dunietz (1987), Kopp and Smith (1983), and Moroney and Trapani (1983). Another method, one which has received attention earlier in the work of Fisher and Pry (1970), is that of the logistic or diffusion function. We believe that the latter method has properties suitable for analyzing current problems of material substitution. The present study thus evaluates this method in its original logistic form as well as an extended version incorporating additional explanatory influences. The analysis is applied to copper/aluminum substitution and iron ore beneficiation. Substitution for copper by aluminum is examined in the building wire and cable, and magnet wire end-use markets. For iron ore, the substitution of pellets for sinter is considered for the U. S. market.

Jan 1, 1990

By T Day, I G. Robertson, G J. Lyman

"Various approaches are used in the industry for establishing procedures (sample mass estimation and method of subsampling) for sampling and analysis of gold ores. The key factors that determine the accuracy of the results that can be expected for a given set of procedures are widely misunderstood.Recent developments in sampling theory show that the estimation of the accuracy that can be expected for a given gold ore as a function of sample mass is actually a simple matter. For a given sample mass, the accuracy that will be achieved depends only on the grade of the ore and the range of masses of the grains of the gold in the ore. This, of course, demands that a reasonable estimate of the distribution or spread of gold grain masses in the ore be known. But this is something that should be known if the gold is to be efficiently recovered in the processing plant.This paper provides a simple explanation of the real facts about sampling of gold, either in the field or in the plant, and provides results for a number of cases of combinations of fine and coarse gold in an ore. The prerequisites for accurate gold sampling are:correct sampling with no loss of sample or contaminationsample preparation procedures that recognise the impact of the gold grain mass spreadpractical analysis of the sample masses required to provide acceptable accuracy.Issues of corporate governance are also discussed.Citation:Lyman, G J, Robertson, I G and Day, T, 2016. The Simple Facts about Sampling Gold Ores, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 159–172 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

In the past decade, the increased engagement of business in debates around sustainable development has prompted recognition of the importance of biological diversity at the local, national and global scales. Driven by increasing populations that demand rising real incomes, a range of human induced pressures are modifying natural habitats and diminishing their ability to support life. Public policy changes have struggled to arrest the loss of habitats such as wetlands or tropical forests, and the related extinction of plant and animal species. Although conservation legislation and regulation were once the exclusive responsibility of government, new partnerships are now being forged that increase the role of the private sector and non-government organisations (NGOs) in developing and delivering conservation initiatives. Since the mid 1990s Rio Tinto has had to adapt to meet the demands of a rapidly changing conservation landscape. When Rio Tinto adopted its statement of business practice in 1998 The way we work, it explicitly recognised the need to take account of relevant environmental factors in obtaining access to lands, particularly in designated areas of high conservation value. With the revision of The way we work in April 2003, the policy on land access was strengthened through removal of the word ?designated?, thereby signalling recognition of the importance of biodiversity outside of protected areas. In addition, Rio Tinto?s revised land access policy explicitly refers to the use of land that is surplus to operational requirements for habitat protection and biodiversity conservation, subject to social considerations. In late 2003 Rio Tinto further strengthened its commitment to biodiversity with the promulgation of its biodiversity strategy and related position statement, biodiversity principles? (See Appendix 1.1) and technical guidance documents. This commitment is also embodied in a variety of initiatives at the corporate and operational levels, which are reported on annually in Rio Tinto?s Social and environment review. This guide has been prepared to support the practical implementation of Rio Tinto?s biodiversity strategy. The purpose is to provide guidance on how to effectively integrate biodiversity into Rio Tinto?s operations. It is applicable to all Rio Tinto exploration, new development projects and operations, irrespective of whether they have been operational for some years or are at the beginning or end of their operational life cycles. This guidance has been developed to support the Rio Tinto Environment Standards and the Rio Tinto Community Standard and any additional supporting documents as they are developed.

Apr 1, 2005

By B. P. Watson

The Bushveld platinum group metal deposits are two distinct, shallow-dipping stratiform tabular orebodies which strike for many hundreds of kilometres. Mining is extensive, with depths ranging from close-to-surface to 2 300 m. The mining method is a variation of planar open stoping. Pillars are widely employed to support the open stopes. In the deeper levels, in-stope pillars are required to fail in a stable manner soon after being cut, and the residual pillar strength is used to stabilize the hanging wall. These pillars are commonly known as crush pillars. Little work has been done in the past to determine pillar peak and residual strengths, and pillars have been designed using experience and formulae developed for other hard-rock mines. This has led to over and undersize pillars with consequential loss of ore, pillar bursts and potential collapses. This paper describes a crush pillar design methodology, and provides design charts. Three mining environments were incorporated in the investigations, which included underground and laboratory measurements, analytical solutions, numerical model sand back analyses. The results of the study are suitable for the areas where the research was carried out, and may also be applied with caution in other similar environments.

Jan 1, 2010

Prof. Henry S. Jacoby, Cornell University,Ithaca, N.Y. (communication to the Secretary): When a simple beam supports any given load, the lower fibers me in tension while the upper fibers are in compression, and if its cross-section is rectangular the neutral surface, where the stresses pass through zero from tension to compression, is at mid-depth, provided the elastic limit is not exceeded. In addition to the longitudinal stresses, there are horizontal shearing-stresses between the fibers which have their maximum value in the neutral surface, and which equal zero at the upper and lower surfaces, while there are also vertical shearing-stresses. Let another beam of the same dimensions be placed on top of this one, and the load be doubled, it then produces stresses in each beam of the same character, magnitude and distribution as in the preceding case, provided there be no friction between the adjacent surfaces of the beams. Next let these two beams be so firmly united that there will be no motion between them when the same load is again applied. All the fibers in the upper beam are now in compression, and those in the lower beam in tension, while the maximum stresses in the outer fibers are only one-half as large as before. The strength of the combined beams is therefore doubled. If, however, some motion occurs between the beams, then the stresses in some of the lower fibers of the upper beam pass from compression to tension, and those in some of the upper fibers of the lower beam from tension to compression, while the stresses in the outer fibers have a magnitude between the two values previously stated. These fundamental facts relating to the flexure of beams indicate the necessity of carefully designing the keys or brace-

Jan 1, 1898

By J. K. Gustafson

Since prehistoric times, gold has been sought for its beauty and its unusual physical and chemical properties. Early in the dawn of civilization it became the ultimate unit of value, and for at least 6000 years it has been used to barter for other commodities. It has been prospected for, treasured and made into works of art and personal adornment. From time to time, it has even been the object of conquest. Because of its predominant role as a basis for money in recent centuries, economists have come to think of gold solely in these terms. Gold, however, has physical and chemical properties that make it one of the most useful metals in the modern world. It is the most ductile metal known. An ounce of it can be drawn into a continuous wire over 35 miles long. It is also so malleable that an ounce of it can be beaten into films 0.00001 in. thick covering 68 sq ft of surface. It has a density of 19.3 and is so heavy that 1 cu ft of it weighs more than half a ton. Gold is nonmagnetic and has a high electric conductivity that is only slightly less than that of silver and copper. Gold is so inert to all the chemicals found in nature that gold coins and jewelry buried beneath the soil or at the bottom of the sea for thousands of years appear to be as bright and perfect as when they were first immersed. Finally, gold has an extremely high reflectivity of both light and infrared rays.

Jan 1, 1971

By Alfred Bellows

The objective was to develop and design a remotely operated temporary roof support system that provides a safe working environment between a freshly cut coal face and the last line of permanently supported roof in which to perform roof bolting activities. This system was to take the form of a retrofit package which could be adapted to a majority of the bolters currently in service. The result is an integrated piece of hardware which will retrofit onto virtually all single boom bolters by removing the drill boom and relocating and modifying the hydraulic controls. The system is composed of three basic components: a pair of cantilevered roof supports which reach forward to the desired line of support, a mast type drill unit for drilling holes and torquing bolts, and a transverse slide assembly to carry the drill from hole to hole across the entry without relocating either the bolter or the roof support. A converted bolter not only provides a much safer operation but is projected to increase the production speed as well as reduce the manpower required to operate a section.. This improvement in productivity is shown to make the job of retrofitting a bolter cost effective in less than two months and provide a potential profit thereafter. Based on the findings presented in this report it is recommended that a proto-type be built and tested in an underground coal mine to demonstrate its effectiveness.

Jan 1, 1976

By Alan E. Gallie

One of the requirements for the successful waging of war is an unlimited supply of iron ore. In the spring of 1941 the demand for iron ore was expected to exceed the supply. This was particularly so in the case of high-grade lump iron ore, essential to the open-hearth process of making steel. The bulk of Canada's iron ore was imported from the United States. At this time, Canada was making every effort to conserve United States funds for more vital purchases. For these reasons, the development of Canadian iron ore resources became of prime importance. Several companies undertook investigations and one of these examined the old Josephine deposit. Location The Josephine property is in the district of Algoma, in the Michipicoten area of the Sault Ste. Marie mining division of Ontario. It is 120 miles north of Sault Ste. Marie and 20 rail-miles east of Michipicoten harbour, on lake Superior (see Figure 1). Transportation in the area is furnished by the Algoma Central and Hudson Bay railway. The Michipicoten branch of this line passes within a mile of the Josephine mine. Michipicoten harbour provides a port through which iron ore is currently shipped. Power in the area is supplied by the Great Lakes Power Company, with generating plants on Michipicoten river, on Montreal river, and on St. Mary's river at Sault Ste. Marie. A series of transmission lines cover the district and one of these is connected to the Josephine mine by a 3 ½-mile branch line. History The Josephine property was staked by Alois Goetz in 1899. Before the claims could be recorded, the township in which they are located was given to the Algoma Central & Hudson Bay railway as part of a land grant. As a result, the ownership remained in dispute until August 24th, 1906, when a settlement was arbitrated by the Honourable Frank Cochrane. His ruling is interesting and is quoted in part.

Jan 1, 1947

By H. B. Hill

Virtually from the date of its discovery in December 1928 the Oklahoma City oil and gas field, Oklahoma County, Okla., has attracted national and international attention. The history of the field has been associated closely with rules and regulations pertaining to production control and proration practices. Early development was rapid, and Oklahoma City soon attained the distinction of being the first major field in which the producing wells were over a mile in depth. Before the structural features of the reservoir had been disclosed every outpost well was considered a "wildcat", so complex appeared the underground geology. The wells not only were deep and the reservoir pressures high, but the production from the early wells was a high A.P.I. gravity oil, accompanied by large volumes of gas. Several "blow-outs" and fired occurred during the early development, and the close proximity of these now unusual events to a large city gave the field much publicity, both local and national. Later, when its production threatened to demoralize the market for oil and its products, the Oklahoma. City field again attracted wide publicity. The then little understood geology of the underground reservoir and the diversity of ownership of the land overlying the producing structure made orderly development and production difficult to enforce. Proration was enforced with difficulty, and the rate of production from the field continued to increase until, on August 4, 1931, martial law was declared in all prorated fields of the State, and most of the wells in the Oklahoma City field wore shut in. On October 9, 1931, permission was granted to reopen and produce the wells in the Oklahoma City field. The order permitting production of the wells provided that during the period beginning October 10 and extending to October 20, 1931, all wells in the field that had not produced more oil than specified under the earlier proration orders and that had been shut in for the required 65-day period were permitted to produce 5 percent of their last potential during that 10-day period.

Jan 1, 1936

By A D. Price, W J. Germs, O Patterson, T R. Weaver

"Understanding controls on groundwater and surface water flow and quality at mine sites throughout all mine stages is critical to effectively manage environmental impacts over the entire mine life. Monitoring forms is an essential component of this proof of understanding. Typically, monitoring programs at mine sites have been developed in the framework of existing conditions. However; recognition of the challenges of climate change and the performance of mines during recent extreme events in Australia has highlighted the need to develop monitoring programs that are resilient and responsive to changing environmental conditions. Water monitoring programs need to be effective under a range of environmental conditions, potentially not historically experienced.This emerging challenge requires cross-disciplinary teams to work together to understand issues including: representativeness of background conditions to longer-term conditions at the mine site sensitivity of mine and closure designs to changing climate and hydrologic conditions methods of performance (eg water quality or quantity) failure during extreme climate events such as flood or extended drought.These understandings come together in a detailed conceptual and, in many cases, numerical hydrologic model that considers the mine-water environment under a range of conditions. The groundwater, surface water and water quality monitoring programs that are developed from the conceptual model need to be sufficiently responsive to be effective in the face of such changing conditions, with results in turn informing the conceptual model. Extended drought, major floods and changing weather patterns can alter recharge and discharge areas, oxidation profiles and ultimately, the contaminant flux estimates that would have contributed to mine design parameters and performance. Unless these effects are considered in the spatial and temporal design of the monitoring program and within the parameters monitored, the resultant program may fail to capture data that are critical to evaluating environmental impacts from mine sites.Developing and implementing a water monitoring program that considers these issues can build confidence in mine performance under a range of conditions, leading to increased confidence by all stakeholders in long-term mine performance during and after closure.CITATION:Weaver, T R, Price, A D, Patterson, O and Germs, W J, 2013. Developing resilient water monitoring programs in changing climate conditions, in Proceedings Water in Mining 2013, pp 109-114 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 26, 2013

By Eric Bain Wasmund, Lance Christodoulou, Julio Jairo Carmona Franco, María Fernanda Castillo, Jose Concha

"A number of technologies are in practice for selectively removing coarse gold from conventional grinding circuits. These circuits are often designed so that the grinding mill output is size classified, with large (or high density) particles being removed before the tails are returned to the mill. Because of the high relative SG of gold, and the fact that some forms of gold such as free gold do not break apart during conventional grinding, coarse gold can accumulate in the circulating load, and eventually be lost.Eriez has developed a flotation cell that uses fluidized water to enhance flotation of coarse particles. More than 40 units have been sold in industrial minerals, and we are now exploring applications for the HydroFloat® in the gold industry.Mineros S.A currently produces approximately 120,000 oz of gold per year by gravity concentrating alluvial gold ore with a mean particle size of 330 microns, followed by further concentration using a Falcon separator. A 400 mm diameter pilot-scale HydroFloat® was added to the tails of the Falcon to test whether additional gold could be captured. Enrichments of 50-600 times and recoveries normally in excess of 95% were achieved. This allowed direct smelting of the gold concentrate. Metallurgical results and operating parameters such as water addition and power will be discussed during the presentation.This result opens the possibility that the HydroFloat® could be used directly in the grinding circuit, for removing coarse gold in the circulating load. This work also shows the possibility that the HydroFloat® can produce a throwaway tail, which will reduce the size of the circulating load stream and the grinding requirements of the circuit."

Jan 1, 2015

By F. Stober, D. Wanblad, J. Ndlovu, L. R. Nelson, L. P. S. de Villiers

The single six-in-line furnace of the Polokwane Smelter is the largest installed high-intensity furnace for platinum group metals (PGM) base metals sulphide smelting in the world. The furnace employs state-of-the art technology to deliver a planned throughput of 650 000 t/a dry concentrate at a design 68 MW power input. This furnace, at double the capacity of previously existing PGM furnaces, offers low unit operating and capital cost through the resulting economies of scale. Key features of the design include:

Jan 1, 2005

By William P. Blake

The ancient city of Guanajuato, the capital of the State of that name, has been built up and sustained chiefly by the milling industry based upon the veins of the Veta Madre and La Luz. It is distant about twelve hours, by rail, from the City of Mexico. Its elevation above the sea is about 6300 ft., and it has a salubrious climate. The population, at the date of my visit in 1891, was estimated at from 80,000 to 100,000 persons. The place is justly celebrated for the antiquity, depth and extent of the mines, the magnitude of the deep shafts, and the enormous total yield of the district in silver and gold, which is comparable with that of the Comstock Lode in the United States. Several important public institutions are located at this center. The State office for the records of claims and of the statistics of mining and production is known as the Deputacion de Mineria. The Mining College, with its fine collection of ores and minerals from the mines of the region, is highly interesting to mineralogists. A mint for the coinage of silver, but not of gold, coins from four to twelve millions of' silver dollars annually. The silver received at the mint is melted in an open-hearth furnace, and is ladled out and cast into long and thin bars, which are rolled down to the proper thickness for the blanks. The bars contain some gold which is not parted. There is an export of dore bars to Germany, amounting in value to from $1,000,000 to $1,500,000 annually. There were, in 1891, upwards of forty reduction-works in and about the city where the silver ores were treated, chiefly by the ancient patio method. In these works were 65 Chilean mills, 301 arrastres of large size, and 936 of smaller dimensions. There were 36 steam engines, but mule-power was generally used at the ar-

Jan 1, 1902

By F. D. Everett

This report, based on information made available by four uranium-producing companies, describes the geology, exploration, open-pit development and mining, and shaft sinking in the Gas Hills uranium district of Wyoming. Open-pit stripping features motor-scrapers push-loaded by crawler or rubber-tired tractors. The ground generally can be ripped, and little blasting is necessary. Detailed data are given on grouting for ground stabilization in sinking a small-diameter shaft in the relatively unconsolidated sandstone and siltstone, Cost and performance data are presented as made available by the companies.

Jan 1, 1963

By F. D. Everett

This report, based on information made available by four uranium-producing companies, describes the geology, exploration, open-pit development and mining, and shaft sinking in the Gas Hills uranium district of Wyoming. Open-pit stripping features motor-scrapers push-loaded by crawler or rubber-tired tractors. The ground generally can be ripped, and little blasting is necessary. Detailed data are given on grouting for ground stabilization in sinking a small-diameter shaft in the relatively unconsolidated sandstone and siltstone, Cost and performance data are presented as made available by the companies.

Jan 1, 1963

By T. Adamcewicz

The province's lignite resources lie mainly in the south, extensions of the much larger deposits in Montana and North Dakota. Because of planned additional capacity, conventional steam power generation will probably remain as the dominant resource usage for many decades. Conversion of coal to other energy forms is receiving emphasis and in the future will compete with steam power generation in terms of quantities used.Economic deposits, minable by present-day technology, have been generally defined. Because a large percentage of the total lignite resource is in seams containing multiple partings, future extraction will become much more difficult and capital intensive.Increased public involvement will ensure that the impacts of future coal mining and usage operations are compatible with environmental and social objectives.

Jan 1, 1982

By K. Adham, C. Lee

Over the last forty years, a number of specific fluidized bed applications in nickel extraction have been developed for commercial use. Five important processes have gained particular acceptance, namely, sulphide ore roasting, nickel sulphide (matte) roasting, nickel oxide reduction, laterite ore pre-reduction, and nickel chloride pyrohydrolysis. These applications involve different feed materials and process conditions, however, all benefit from fast reaction kinetics and high heat and mass transfer rates in the fluidized bed reactors. They have been studied, tested, and implemented by various nickel producers, who have published their results in many papers and patents. This paper examines the design issues surrounding the application of fluidized bed technology to the above nickel processes. Based on the available data in the open literature, computerized process modelling is used to provide generic flowsheets that illustrate the key features of each process.

Jan 1, 2004

By G. Stecklein

This report summarizes the results of research into the areas of the fragmentation and entrainment of Airborne Respirable Dust (ARD). The objectives of this program were four-fold: first, to review the present state of knowledge regarding ARD; second, to expand this state of knowledge through the identification of hypothetical microscopic mechanisms by which the coal is fragmented and the dust becomes entrained; third, to specify the informational requirements to verify or nullify these hypotheses; and fourth, to relate experimental techniques that will produce that required information. Additionally, insights are provided regarding potential methods of extraction and/or treatment which may reduce the concentration of ARD.

Jan 1, 1982

By Evelynn Stirling

Agenda ? Emissions legislation ? Cummins Tier 4 Technology ? Cummins Experience with Technology ? Operation and Maintenance Impact The Emissions Challenge ? The 2014/5 emissions regulations present the most significant challenge to our customer?s diesel powered equipment design and operation in recent history? ? ?and Cummins has the solution.

Aug 1, 2013