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By Harry Perry

The decline in coal production has been slowed somewhat in recent years, mostly because of the industry's own remarkable success in holding the line on costs, and partly as a result of advances achieved through industry and government research. Nevertheless, the decline has continued. This downward trend combined with the increased productivity of labor through mechanization that has been necessary for coal to retain even its present competitive position, has resulted in a serious reduction in the number of miners required and large scale economic dislocations in mining communities. For coal to regain a more favorable position it must either expand existing markets by reducing the cost of the delivered product and thereby compete more effectively with other fuels or develop new uses that will require large tonnages of coal. New markets involving several million tons, which would look extremely attractive to most other United States industries--including the organic chemical industry--would do little to alleviate the coal industry?s depressed economic conditions, While such small new markets would be welcome, an industry producing over 400 million tons per year must look to large tonnage outlets for solutions to its long range economic problems.

Jan 1, 1964

By C. Fortin

ABSTRACT The subject of gold flotation has been reviewed extensively. Most of these reviews focus on the theories of gold flotation and the physical and chemical effects that may impact the efficacy of the gold flotation process. The current status of gold flotation chemistry as it is being applied in industry has not been widely addressed. This paper reviews current gold flotation practice and research advancements and discusses how these applications tie in with the current understanding of gold flotation chemistry. Survey results from worldwide gold flotation operations are analyzed. Potential future areas of gold flotation research are highlighted.

Jan 1, 2013

By Mory Ghomshei

Pebble Creek Geothermal Power project is associated with a massive recent volcanic eruption in Southwestern British Columbia Canada. Slim holes drilled to depths 1100 m in the prospect area, show very high temperature gradients around 80?100?C/km. The temperature and chemistry of the Pebble Creek hot springs indicate the possibility of a steam reservoir in the prospect area. In addition to high temperature gradients, presence of host rocks with high permeability, along with abundance of recharge waters (from the Lillooet River) provides clear signature of a high-grade geothermal power reservoir at depth 2000 to 3000 m. Data show that over five hundred Megawatt of green power can be generated from the prospect area in a commercially viable manner. The generated power will be base-load, which in comparison with large hydro has the advantage of lower capital costs and a significantly smaller footprint. The final hurdle to overcome, before starting the development phase, is deep exploratory drilling for resource confirmation. This paper is a summary of the data available on the Pebble Creek geothermal power prospect, presented in the context of viability of the resource for large-scale commercial power generation.

Aug 1, 2013

By K J ROSENGREN

Underground rock mechanics was initiated as a formal discipline in Australia by early studies for underground structures for the Snowy Mountains Scheme in the 1950s. These techniques were quickly embraced by underground mining and there has been steady development to the present time. The paper reviews the status of current techniques for rock mechanics studies and discusses some important issues such as ground support, mine filling and caving. It concludes that a considerable degree of engineering judgement is still required for the practical application of rock mechanics to underground mine design.

Jan 1, 1992

By Earle J. Klohn

Tailings disposal has rapidly become an area of increasing importance to both existing and planned mining operations. In recognition of the significance of this topic, MINING ENGINEERING is presenting a series of articles on tailings disposal. The first, published in June, outlined some site criteria that influence tailings disposal and some of the design options available to meet these criteria. The following article explores in more detail important design criteria for tailings dams and provides several case study illustrations.

Jan 7, 1981

By Greg Gosson

These materials are provided for general information purposes only and do not constitute legal advice. Readers are advised to seek specific legal advice from their own counsel in relation to any decision or course of action contemplated. Outline ??What is meant by a ?current technical report? under NI 43-101? ??When is a current technical report required? ??Who makes the decision regarding whether a technical report is current? ??Examples of the types of information that make a technical report no longer current for securities filing purposes.

May 1, 2009

By Nelson Severinghaus

AS far back as 40 years ago management made the initial steps toward utilizing the large amount of reject marble produced by the dimension stone quarries in sized products. In 1947 the Calcium Products Div. of the Georgia Marble Co. was organized to manufacture crushed, ground, and screened products from Georgia marble.* It became obvious early in operations that salability of any products of this type was determined by several factors: high calcium carbonate content, whiteness, dryness, and cleanness. Because no reject material could consistently meet these specifications, Calcium Products Div. now operates three underground quarries for raw material feed. In underground operations no stripping is required, surface contamination and trash are eliminated, weather causes no operational difficulties, and the raw material is maintained dry for plant processing.

Jan 12, 1957

By William E. Torres

The Southern Peru Limited smelter, in Ilo, operates two reverberatory furnaces, seven Peirce-Smith converters, one Teniente Converter, two casting wheels and a single contact acid plant. The Teniente Converter was commissioned in August 1995 and was designed to smelt 744 dry metric tons (820 dry short tons) of concentrate per day. The process off-gas is collected in a water-cooled hood, cooled in a spray chamber, and cleaned in a Joy electrostatic precipitator for further treatment in the Acid Plant. This paper presents the current Teniente Converter operating practices and control philosophy. Relevant improvements and modifications to achieve a 379 day campaign without tuyere replacement and a daily average smelting rate of 862 dry metric tons (940 dry short tons) of concentrate are discussed.

Jan 1, 1998

By L. Gilbert

Recent changes to environmental legislation and trends in the environmental regulation of mining in the Northern Territory are being driven by (among other factors) Federal Government policies and international agreements on the environment. These trends are discussed and the expected application of the NT Water Quality Management Strategy (based on the National Water Quality Objectives) over the next few years is examined with respect to mine environmental management practices. Some of the potential conflicts and changes in approach which may develop are identified and examples discussed. Proactive means of integrating trends in environmental legislation with mine planning and waste management are discussed.

Jan 1, 1994

By Robert B. Parsons

Since 1978, new tax measures affecting the mining sector have been relatively favourable, evidencing a moderately enhanced government awareness and sensitivity towards the industry's concerns. Today, although the industry continues to face a complex and sometimes capricious tax system, a wide range of tax provisions offer some excellent opportunities to the industry. This paper examines the basic features of the present tax environment, discusses some of the more important changes of recent years, and comments on the outlook for mining taxation in Canada.

Jan 1, 1985

By Smith I. T

Mine operators have long recognised that the results achieved in primary blasting are critical to subsequent mining activities. With the introduction of "in the hole" drills under- ground and the advantages offered by the use of water gels in conjunction with ammonium nitrate-fuel oil (ANFO) explosives, new mining methods have been developed and enabled improvements in older methods. Pumpable water gels have been used with varying success underground. These gels allow a high loading density even in ragged bore- holes. The problems encountered with slumping in upholes is recognised so the current trend is to use these gels in downholes where wet holes are prevalent. Cartridged water gel technology has advanced to the point where it has allowed the replacement of nitroglycerin (NG) based explosives and pumpable water gels. Today, gels can be made as a tampable product for use in development headings or as a slump- ing product for downholes to give an effective coupling. With the introduction of the Tovex« pneumatic loaders, the problems associated with a pumpable gel were eliminated and gave the user the ability to alter his loading density.

Jan 1, 1977

By R. B. Throndycraft

"1. Belt-Drop Agglomeration Preferred at Heap Leach Operations. The agglomeration method now preferred at heap leach operations utilizes belt-drops along conveyors. Belt-drop agglomeration is being designed into numerous upcoming heap leach operations. It offers substantial capital cost savings over previously favored drum agglomerators. It has such significant operating and maintenance advantages that some drum agglomerators have been retired in favor of belt-drops.The majority of heap leach operations are now built with crushing included in the flowsheet. If crushing is included, belt-drop agglomeration can be added for almost no cost. The agglomeration equipment is simply a few conveyor transfers, designed to provide the tumbling and rolling action which forms the agglomerates. Controlled water sprays are needed at each of these agglomeration transfers. Cement or lime is added as a binder, to stabilize the agglomerates. This reagent is also needed to raise pH to safe operating levels.Addition of the pH control reagent before stacking the ore offers a reagent cost benefit. In the belt-drop mixing technique, the ore is intimately mixed with the lime (or cement). After stacking on the heaps, when the cyanide solution is sprayed onto the high-ph ore, very little cyanide is consumed. Without the pre-addition of lime or cement, the leach solution is sprayed onto neutral ore. The mixture of high-pH leach solution and neutral pH ore causes the solution pH to drop, releasing cyanide gas. This release is minor from a safety viewpoint, much less than dangerous, but the gas release is a costly waste of the cyanide reagent. Pilot-scale comparison tests were made at Pinson. Ore pre-treated with lime or cement showed 30% less cyanide consumption than untreated ore."

Jan 1, 1989

Ground falls (roof and rib) have historically been responsible for nearly 50% of all fatalities in bituminous underground coal mines. In recent years, the number of some annual ground fall fatalities has approached zero, indicating that significant progress has been made. On the other hand, the twin disasters at Crandall Canyon in 2007, in which nine miners perished in violent coal bumps, provided a stark reminder that complacency is premature. One important success has been a great reduction in the number of miners killed inby roof supports. Throughout the 1990s, these accounted for nearly half of all roof fall fatalities, but there have just been two inby incidents since 2005. Progress has also been made in pillar recovery, where there has been just one fatal incident since 2005. On the other hand, more than 300 miners continue to be injured each year by rock falling from between supports and 100 more are injured by rib falls. Together, these two categories also account for a large percentage of recent ground fall fatalities available technologies such as roof screen, rib bolting and inside control roof bolters could reduce injury and fatality rates if they were used more widely. Further advances in these areas will likely be the next big advance in ground control safety.

Jan 1, 2011

Ground falls (roof and rib) have historically been responsible for about 50% of all fatalities in bituminous underground coal mines. In some recent years, the number of ground fall fatalities has approached zero, indicating that significant progress has been made. On the other hand, last year?s Crandall Canyon twin mine disasters, in which 9 miners perished in violent coal bumps, provided a stark reminder that complacency is premature. One important success has been a great reduction in the number of miners killed inby roof supports. Throughout the 1990?s these accounted for nearly half of all roof fall fatalities, but there have just been two inby incidents in the past 5 years. Progress has also been made in pillar recovery. Safer mining technologies have reduced the number of fatal incidents, but some recent failures have underlined the need for careful management of the retreat mining process. On the other hand, more than 400 miners continue to be injured each year by rock falling from between supports, and 100 more are injured by rib falls. Together, these two categories also account for a large percentage of recent ground fall fatalities. Available technologies such as roof screen, rib bolting, and inside control roof bolters could dramatically reduce injury and fatality rates if they were used more widely. Further advances in these areas will likely be the next big advance in ground control safety. Disclaimer: The findings and conclusions in this report have not been formally disseminated by the National Institute for Occupational Safety and Health and should not be construed to represent any agency determination or policy.

Jan 1, 2009

By V. H. Forsythe

Mr. Chairman, members of SME, and guests It is indeed a pleasure to have the opportunity to appear before this group. The topic of this paper is, "Current Trends in Related Industries and Their Influence on Electric Shovel Design and Size". Before getting into the major items, it is well to point out that this text will deal with loading shovels primarily, since their application is almost universal in major open pit mining operations throughout the world. Related industries influence our design in many ways. For the sake of simplicity, these industries will be broken down into two major categories. The first category to be discussed will include industries that will indirectly influence design and size, while the second category will include industries whose products can directly be incorporated by the engineer in the design of shovels.

Jan 1, 1964

By C. P. Mangelsdorf

The success of the Birmingham roof truss (Figure 1) in supporting some difficult roof conditions, particularly in the Illinois coal basin, has given impetus to the development of a number of alternate schemes. These schemes attempt to alleviate two major problems with the Birming-ham truss, namely, the time required for installation and the cost of material. Because of the difficulty of drilling angled holes and the number of different pieces of hardware which must be handled manually, most operators have been unable to install Birmingham trusses in the cycle and have had to schedule truss crews during the maintenance shift or whenever they would not impede production. Due to this delay the truss has traditionally been viewed as a supplemental form of roof support. In fact, the truss might qualify as primary support and replace at least two bolts if it could he installed in the cycle (and MSHA would accept it as an alternate in the roof plan.) [ ] Figure 1. The Birmingham truss. Two attempts to deal with the first difficulty have sought to streamline the truss hardware while preserving the essential character of the Birmingham truss. One of these, by Peabody Coal, is reported elsewhere in these proceedings by C. Bollier. Another is a contract issued by the Bureau of Mines to Bendix Corporation for the development of a machine, particularly suited for use in low coal, which will automate many of the operations currently executed manually. This machine is expected to be ready for field testing by fall of 1982. Once in place, a truss installed by either of these schemes will interact with the roof in the same way as a conventional Birmingham truss. An alternate approach has been proposed by several different manufacturers independently. Although the hardware details differ. the essential idea consists of two angle bolts, the heads of which are connected by a horizontal chord tightened to some pre-determined tension. Figure 2 shows the generalized concept and does not depict any one of the four systems proposed. The advantage of this scheme is that the angle bolts can be installed and tightened in the cycle, and as bolts, immediately satisfy the roof control plan. The horizontal chord can be added later to achieve almost any initial desired roof loading, the limits of which are defined below this scheme is referred to here as the angle-bolt truss. Because of a fundamental difference in the way in which load is transferred between chords, this design does not interact with the roof under subsequent loading in the same manner as a Birmingham truss. The purpose of this paper is to examine this fundamental difference and its consequences. [ ]

Jan 1, 1982

By G. Karahalios

Industrial minerals have always enjoyed an important share in the technological growth of any country in the world. Today, extraction and trading of industrial minerals has expanded, but is also subject to stricter environmental guidelines. This paper presents the current status as well as the growth potential in the exploitation of industrial minerals in the countries of the south eastern European region, i.e. Albania, Bosnia-Herzegovina, Bulgaria, Croatia, F.Y.R.O.M., Greece, Italy, Serbia and Montenegro, Slovenia and Turkey. More specifically, annual production figures per country are presented for1992-1998. These figures are compared to each other and, where applicable, to world production figures. Trading of industrial minerals from these countries to Europe and the world and its effect to the local economies is also evaluated were such data is available.

Jan 1, 2000

By Robert B. Parsons

"As the 1981 annual reports of Canadian mining companies one by one see the light of day, it becomes clear that softer metal prices and rising costs are the main problems which beset the industry today. These problems are certainly not lightened by that familiar monster lurking in the shadows-taxation! Recent taxation trends in Canada, and the existing tax regimes for the mining industry, continue to be a major bugaboo.This examination by ""Tax Notes"" of the impact of current taxation trends on the mining industry is based on a speech delivered recently by Robert D. Brown, senior tax partner of Price Waterhouse, Canada, to the annual meeting of the American Institute of Mining, Metallurgical and Petroleum Engineers in Dallas.IntroductionThe purpose of this paper is to tell a story-and it is a story with a moral. The first thing to recognize is that, with depressed metal prices and weakening western economies, high taxes, in and of themselves, are not really the cause of the Canadian mining industry's present doldrums. However, the character and level of mining taxes in Canada has had a profound influence on the development of the industry over the past decade, and the expectations of what the future holds for mining men in Canada will equally play an important role in the future development of the Canadian industry. Our tax system has, in the past, served as a negative and destabilizing influence in the mining industry: it has contributed to a major short-fall in investment commitments and hence in the contribution which the mining industry can make to the Canadian economy, and the adverse effect on the industry of previous high marginal tax rates was made far worse by the confusing, contradictory and perverse nature of the tax system itself."

Jan 1, 1982

By Robert D. Brown

The purpose of this paper is to tell a story - and it is a story with a moral. My topic is Present Trends in the Tax Environment Affecting Mineral Development in Canada, and the first thing to recognize is that, with depressed metal prices and weakening western economies, taxes, in and of themselves, are not really the cause of the Canadian mining industry's present doldrums. But the character and level of mining taxes in Canada has had a profound influence on the development of the industry over the past decade, and the expectations of what taxes the industry will face in future years will influence the industry's further growth. My theme today is that, in Canada, our tax system has, in the past, served as a negative and destabilizing influence in the mining industry: it has contributed to a major short-fall in investment commitments and hence in the contribution which the mining industry can make to the Canadian economy, and the adverse effect on the industry of previous high tax rates was made far worse by the confusing, contradictory and perverse nature of the tax system itself. This is a story with some happy parts in it, and, in fact, governments in Canada did learn, haltingly and grudgingly, that there are limits on the amounts that governments could safely extract from the industry, and that some assurances of long term fiscal stability were necessary if investors were to be induced to make massive commitments which could only be recovered over very lengthy periods.

Jan 1, 1982

By A. J. S. Spearing, A. Mueller

The support of intersections in coal mines remains an important safety issue, mainly because the large diagonal span compromises the stability of the roof. This structural weakness is further exacerbated if the intersection is developed incorrectly, the pillar corners fail or the crosscuts are angled (not perpendicular). This report details the current support systems used and investigates unplanned falls of ground in intersections in coal mines throughout the United States. A possible failure mechanism is proposed and some suggestions are made to improve the effectiveness of the support in these vital areas.

Jan 1, 2009