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By H. Nan

Using the case of Qianqiu Mine, Yima Coal Mining Administration, theoretical analysis, laboratory physical simulation, and underground observation were performed to study the major parameters for fully mechanized sublevel caving mining method, including drawing spacing, drawing sequence, drawing numbers, and number of shields performing simultaneous drawing. The effects of those parameters on coal recovery and amount of waste rocks were also investigated. The optimal coal drawing technology for this case was obtained.

Jan 1, 2006

By J. A. McCamley

Gypsum scrap generated from wallboard manufacturing, construction and deconstruction activities in North America, Europe and Japan is a recognized environmental problem. Landfill disposal of this gypsum scrap is problematic, with deposits often creating hydrogen sulphide emissions and metallic sulphide groundwater leachates. Of these regions, Europe is the most advanced in dealing with the issue having enacted legislation, which will come into effect in July 2005 that will strongly encourage gypsum recycling throughout the EU. An estimated 10% to 17% of all gypsum used in the wallboard industry becomes recyclable scrap, which represents approximately 1% of the total waste stream in North America. In the United States, 2.5 to 4.5 Mt of gypsum scrap is generated each year; the volume is similar in Europe (the percentage of total tonnage is less because of the higher use of brick and concrete). The Greater Vancouver region of British Columbia has banned gypsum from its landfills, and as a result, all gypsum scrap is now recycled. New West Gypsum Recycling, a Canadian firm, uses its proprietary technology to process large quantities of gypsum scrap that is reincorporated into new wallboard, at percentages ranging up to 25%. The operation of New West Gypsum Recycling Inc. of Langley, Vancouver is examined as a case study and recommendations are provided as to how other urban regions can implement similar gypsum scrap recycling programs.

Jan 1, 2004

Prediction of fragmentation by blasting is most commonly based on theassumption that a single distribution of pre-existing discontinuities is present within a blasted rock volume and that the underlying mechanism of failure is tensile failure. It is assumed that the tensile stress field created by a blast initiates and extends radial cracks around the blastholes. Interaction between radial cracks from different blastholes and the free surface creates rock fragments. In reality, fragmentation of the rock occurs due to two mechanisms.One is related to the compressive-shear failure of the rock (mainly rock matrix) close to the blastholes, while the second mechanism is the previously mentioned tensile failure of the rock mass. The secondmechanism of failure occurs in the form of extension of the larger cracks in the region beyond the crushed rock, and this type of fragmentation occurs after the crushing phase. In the case of hard rock or blasting where the extent of crushing is minimal, the currently used prediction methods give a reasonably good result. However, there are many blasting conditions where the amount of rock crushing is significant. In the case where fragmentation of the given rock volume occurs dueto two different mechanisms, modeling of the rock fragmentation with a single distribution function is not appropriate. To model the fragment size distribution generated by two different mechanisms, it is necessary to use a two-component fragment size distribution function and a scaling parameter that will determine the proportion of the fragmented volume created by each mechanism. The purpose of this paper is to present results of blast fragmentation modeling based on two mechanisms of failure. The two-component model (TCM) utilises experimentally determined parameters from small scale blasting and parameters of the Kuz-Ram model, for more accurate prediction of the complete rock fragment size distribution curve. The methodology is such that it is possible to predict complete fragment size distribution, including fines, of ROM product for a future mine, at the feasibility phase of mine design.

Jan 1, 1999

CHAPTER 1 - GENERALIn the introduction to this chapter a general account is given of the growth of the mining industry in Western Australia from J88G, when the output of gold for the whole State was only £1148, to 1908, when: the output had risen to £6,999,885. In 1903 the output reached £8,770,719.It is quite evident that the discovery of gold in Western Australia was the means of opening up the road to broader industrial expansion, and it is doubted if any other portion of the British Empire more clearly exemplifies the nation-building forces of metalliferous mining than this State.The chapter includes an account of the following situation and history of the field.CHAPTER 2 - GEOLOGYIn this chapter the classification of the rocks of Kalgoorlie, but particularly those on the Golden Mile, is considered. Each rock is described in detail, and microphotos are shown to indicate the most important features in each type. As far as the Golden Mile is concerned, it is held that, notwithstanding the general chemical and more or less dynamical metamorphism which the rocks have suffered, it is possible to divide them into six groups...

Jan 1, 1912

By Mary C. Nodine, Michael P. Walker, Paul Eggers, Donald E. Aubrecht

The CANALSIDE commercial development in Buffalo, New York serves to revitalize the former site of the Buffalo Memorial Auditorium, adjacent to Lake Erie. The Auditorium was constructed in 1940 and founded on steel H-piles driven to limestone bedrock. After decades of professional sport and entertainment events, the “Aud,” as it was locally known, was closed in 1996. It sat vacant until it was demolished in 2009, at which time plans were made to revitalize the area with shops, restaurants, and a historic replica canal. The only portion of the Aud that was left intact was a subbasement boiler room. The subbasement was renovated in 2014 and has since been used to house water and ice making equipment for the historic replica canals, which boast recreational ice skating in the winter. The subbasement floor was about 10 feet below groundwater and the Lake Erie water level. The floor consisted of an approximately 4-foot-thick layered inverted waffle slab system, with reinforced concrete grade beams and concrete infill between the grade beams. A waterproofing membrane was located near the base of the slab. There were no major seepage issues in the subbasement, so the existing waterproofing membrane was assumed to be intact and performing adequately. A four-story building housing a children’s museum was proposed to be constructed directly above the subbasement. The loads imparted by the new building would exceed the capacity of the existing piles, so it was determined that drilling micropiles through the subbasement floor would be the most practical means of supporting the new building. Drilling through the existing slab and waterproofing system was a concern due to the challenges of controlling water during construction and the importance of maintaining the integrity of the permanent waterproofing system.

Jan 1, 2018

By J. L. Moreno, A. L. Williamson, R. D. Bartlett

Large open pit mines in desert climates, such as the Phelps Dodge Morenci copper mine in Arizona, can create groundwater cones-of-depression of considerable size and stability. The hydraulic containment provided by the groundwater depression prevents migration of process solutions into the surrounding regional aquifer. Copper leach operations that fall within the groundwater depression may not require costly lining if passive containment can be demonstrated. An approach is presented in this paper that was successfully used to demonstrate passive containment. The approach includes a combination of groundwater modeling and a water balance analysis of leaching operations failing within or immediately near the open pit.

Jan 1, 1999

By GUY C. RIDDELL

ZINC, manganese, and aluminum received attention at the two nonferrous metallurgy sessions at the Annual Meeting. L.P. Davidson, general superintendent of the rebuilt Monsanto zinc plant, described its operation, which reflects Polish practice and is really a combination of electrolytic, Waelz, and retort procedure. Briefly, it embraces leaching of roasted concentrate with sulphuric acid, electrolysis of sulphate solution using Tainton lead-silver anodes with ?goulac? added to the electrolyte, treatment of tailing in Waelz kilns, and retorting of the recovered zinc oxide, casting furnace dross and residues. Recovery is good, equipment and maintenance costs low. Ferrate zinc that might be lost in the electrolytic process appears to be recovered as oxide in the Waelz treatment.

Jan 1, 1942

By Charles L. Kimbell

For the world mineral industry as a whole, the year 1981 was a period of continuation and, in some instances, an acceleration of negative trends extending back into 1980. Most available statistical data reflected stagnation or downturns in activity. Levels of production, trade, and consumption declined for a substantial number of leading mineral commodities, including, most notably, steel and petroleum. Investment, if not lower than in 1980, was evidently increasing at a more modest rate. Prices for major mineral commodities were generally lower, at least in terms of constant dollars, and in some cases even in terms of current dollars. Prospects of a major reversal of these patterns seemed dim. The mineral industry, however, was far from alone in this general downturn; most other elements of the national economies of the world's nations fared little better. General conditions of inflation, recession, and reduced industrial product consumption were reflected in most other sectors of the total economy. International political events continued to influence mineral output and flow but had less influence on overall levels of activities than on the geographic distribution of these activities. The Iran-Iraq war certainly played a role in reducing mineral industry activities in those nations, but the commodity most affected, petroleum, was available from other sources in sufficient quantity that, in the face of reduced demand, a substantial surplus developed.

Jan 1, 1983

By Jacques J. Eksteen

Metallurgical accounting around toll treatment smelters pose a number of challenges. This paper reviews the requirements for good sampling practice, and how conflicting requirements for good furnace operation and design often makes reliable closure of the metallurgical balance tenuous at best. Typical physical causes of variance and bias will be identified. The propagation of error (in the form of variance) will be discussed for a copper smelter.

Jan 1, 2006

One of the important directions of further increase of quality and efficiency of control of mining companies and branches is the creation of the operation and development monitoring systems of such facilities. The main purpose of these systems is to provide managers with reliable and timely information on the current state and typical tendencies of operation of the facilities under control. However until the present time no scientific and methodical ground for system monitoring of the mining companies and branches has been created. Therefore, the authors of the report have aimed to assess the current situation with regard to the researches in this field and to do analysis of the most important aspects and ways of solution of the issue under consideration.

Dec 6, 2010

Poorly designed sampling protocols generally result in high project risk by artificially increasing grade variability (ie the nugget effect). Sample collection, preparation and assay protocols that suit the ore type, together with QA/QC systems, will reduce this risk. All reporting codes (eg JORC, 2004) require the Competent Person to consider the quality and implication of sampling and assaying programs. High sampling errors beget higher project uncertainty; despite this fact, sampling does not receive the attention it deserves. The case studies presented show that many sampling issues frequently go unrecognised or unaddressed, resulting in poor project decisions during exploration through to feasibility and production. The overall conclusion is that correct sampling is critical to mining project success and that there is often a need for its optimisation.

Jan 1, 2007

By Thomas. L. O.

Apart from a few sketches and incomplete maps, mainly topographical, and one or two detailed maps of placer-creeks, there is little information on the topography and geology of most of the country adjacent to the sections of the Alaska Highway in the Liard River area, particularly that part east of Kechika river. In 1943, the Geological Survey of Canada made a recon-naissance from Fort Nelson clown the river of that name to the Liard, thence up the latter to Hell Gate, and also up Beaver river for a distance of fifty miles. The whole of the area covered was found to be underlain by sedimentary rocks, not a single igneous dyke being seen. The British Columbia Department of Mines began reconnaissances near the highway both in and north of the drainage basin of Prophet and Muskwa rivers with a view to finding structures favourable for the accumulation of oil. In Liard River valley near the mouth of Smith river and at intervals from there clown to Devil' s Portage occur warm springs whose character and origin are not definitely' known, since they have not been investigated (21, p. 38A). Similar springs are said to occur at several localities over a broad belt extending from Muskwa river across the Liard to the Nahanni River country (26, p. 11). On Liard river below the mouth of Dease river, stratified sands, gravels, and clays of Pleistocene (?) age are constantly met with and in one or two places are underlain by sandy clays. The distribution of the latter, however, is very limited in the section cut by the river west of the Rocky mountains. The only range of these mountains that reaches the Liard is the high limestone ridge which approaches the mouth of Vents river from the southeast and then almost vanishes a few miles to the northwest of it (27, pp. 43-45). In general, the ranges of the Rockies in the area under consideration have been but little explored, but they are undoubtedly very largely sedimentary and, with the exception of some volcanics and intrusives on their western flanks, are probably almost entirely so. Unlike the high, deeply incised ranges in southern British Columbia, they dwindle in elevation north of Terminus mountain to low-wooded ridges separated by wide swampy valleys, and practically lose their identity between it and the Liard. The foothills, which, along the Liard, have a width of 38 miles (from near the mouth of Trout river to Hell Gate) are composed of a great series of alternating shales and sandstones, with some limestones, all folded closely together, which resemble those found in the foothills farther south (27, pp. 50, 19-20).

Jan 1, 1944

Coal mining in Indiana is limited to the south-western portion of the state, with coal currently being recovered in 19 counties. The coal-producing area of the state covers approximately 6,500 square miles. Although most of the coal in Indiana is recovered by surface mining methods, a small percentage is recovered through underground mining. To date, 40 percent of the known coal reserves have been removed. Indiana has about 33 billion tons of identified coal reserves, of which approximately 17 billion tons are recoverable using current technology. Of this recoverable coal, about 15 billion tons are recoverable by underground mining and 2 billion tons are recoverable by surface mining methods. The State of Indiana has regulated the environmental impacts of coal mining since 1941. Indiana was the second state in the nation to pass legislation requiring mined land reclamation. Its SMCRA regulatory program was approved July 29,1982, and its Abandoned Mine Land Program was approved July 29, 1982.

Jan 1, 1992

Jan 1, 1944

Jan 1, 1944

By Douglas D. Reynolds

Intense vibration can be transmitted to the hands and arms of workers who use hand-held percussive or vibrating devices, tools, and work pieces. Continued habitual exposure to vibration directed to the hands can cause patterns of various symptoms associated with hand-arm vibration syndrome (HVAS). The International Organization for Standardization (ISO) first published ISO 5349 in 1986.3 This standard specified methods for measuring and evaluating vibration directed into the hands from hand-held vibrating devices, tools, and work pieces. The American National Standards Institute (ANSI) published ANSI S3.34 the same year.1 This standard was modeled after ISO 5349-1986 and specified methods for assessing exposure to hand-arm vibration. The Parliament of the European Union has issued the European Union Human Vibration Directive-2002/44/EC, which specifies vibration daily exposure action values (DEAV) of 2.5 m/s2 and daily exposure limit values (DELV) of 5.0 m/s2. These values have generally been accepted by medical experts, scientists, and engineers in governmental agencies, research institutions, and industry in the USA and other countries.2 When they are achieved, they will reduce the potential for the development of symptoms related to HAVS among workers exposed to hand-arm vibration. Significant improvements in measurement and analysis instrumentation, miniature and subminiature accelerometers, and medical diagnostic and assessment protocols have being introduced since 1986 when ANSI S3.34 was first published. In response to these improvements and the introduction of the EU Human Vibration Directive, ANSI Working Group S2.39 developed the revision to ANSI S3.34, which has now been published as ANSI S2.70-2006.2 Method ANSI S2.70 specifies the use of the hand-arm vibration measurement procedures outlined in ISO 5349, Parts 1 and 2.2,4,5 It requires the measurement of ISO frequency-weighted acceleration values in three mutually orthogonal axes of vibration. These values are then vectorially added to obtain the vibration total value, ahv: [ ] where ahwx, ahwy, and ahwz are the measured r.m.s. ISO frequency-weighted acceleration values in the x, y, and z directions, respectively. If multiple vibration exposure events are experienced during a work day, the overall vibration total value is obtained from: [ ] where ahvi is the vibration total value of the ith operation, Ti is time duration in hours of the ith operation, n is the total number of operations, and T is total time in hours associated with the n

Jan 6, 2006

By F. S. Boericke

"INTRODUCTION The mineral found in natural-chromite deposits is never pure Fe0.Cr203, but rather one in which the Fe0 and Cr203 are in part replaced by Mg0 and A1203, respectively. The purest gravity concentrates from many domestic de¬posits consist of a mineral referred to as ""picotite,"" in which this isomorphous replacement is such that the ratio of chromium to iron is low. The Bureau of Nines has investigated methods of chemically beneficiating ores that contain too much iron to be classed as ""high-grade"" chromite 3/ Early investigations 4/ demonstrated that high-iron chromite or picotite ores can be roasted with carbon to obtain selective reduction of the contained iron, and that most of this reduced iron can be removed by acid-leaching the roast products to produce residues of higher chromium-to-iron ratios. tests 5/ indicated that commercially acceptable reaction rates cannot be obtained at roasting temperatures below 1,3000 C., using solid carbon as reducing agent. By this high-temperature reduction and subse¬quent acid-leaching, however, all ores investigated, regardless of the original composition, readily yielded residues considerably better than the minimum specifications for high-grade chromite.In an effort to obtain satisfactory reduction of chromite at lower temperatures, liquid and gaseous seducing agents were tested with varying success. Of the several reducing agents used, methane appeared to be the most promising and was shown to be highly effective at temperatures between 1,000º and 1,100º C., roughly 300º below the roasting temperatures necessary in solid carbon reduction. Further experiments indicated that mixtures of methate with some diluent (hydrogen or other nonoxidizing gas) gave better reduction than did methane alone."

Feb 1, 1946

By R. D. Lawrence

"Comparable transaction analysis is the best known of the market approaches to valuation of exploration-stage mineral properties. The analysis of option and farm-in agreements can also provide useful guidance to valuators. While such approaches can be distorted by incomplete analysis, market-based methods are capable of providing consistent, credible results when carried out carefully with due consideration paid to all factors which buyers and sellers consider when dealing in the real market. IntroductionMineral properties without defined resources present one of the most challenging tasks to the mineral valuator. This paper will concentrate on market-based approaches to valuation of such properties. Other authors at MM2000 presented papers on cost and income approaches. Sorentino (2000) also provides a useful overview with some provacative commentary on methods.Market based-approaches are based on the principle of substitution and include such techniques as: comparable transaction analysis (sometimes referred to as sales comparison analysis); farm-in commitment (or option agreement) analysis; rules-of-thumb; and comparable market value analysis.Are there any valuation standards available to assist the valuator? In Canada there are none that apply to the valuation of mineral assets or securities. This problem is being addressed, at least in part, by the CIMVal Committee of the Canadian Institute of Mining, Metallurgy and Petroleum (CIM)1. Further, the recently established Canadian Association of Mineral Valuators will be giving consideration to the adoption of valuation standards."

Jan 1, 2002

By C. M. Harrer

Reconnaissance investigations were made of 129 iron occurrences in Arizona to determine their extent, attitude, and potential; character samples were analyzed to determine their quality and impurities; and pioneer metallurgical investigations were made on character samples to present their metallurgical problems. Some factors influencing past and potential western iron markets are discussed. The location, features, qualities, extent, and potential of iron occurrences and some associative resources--limestone and dolomite, coal, petroleum and natural gas, power, and water are discussed. The most abundant iron minerals are magnetite and hematite. The higher grade deposits are extensive contact-metamorphic or pyrometasomatic replacements of calcareous Paleozoic to Proterozoic rocks associated with intrusives. Large low-grade deposits of great potential are present as Precambrian taconite, semitaconite-, and jaspilite-like iron formations of magnetite-hematite. Iron occurs also as low-grade concentrations of magnetite in extensive alluvial deposits. Nonferrous metallurgical slags, nearly 100 million tons, are considered a potential source of iron. Various accessory elements are associated with the iron minerals and these pose metallurgical and economic problems.

Jan 1, 1964

By C. M. Harrer

Reconnaissance investigations were made of 129 iron occurrences in Arizona to determine their extent, attitude, and potential; character samples were analyzed to determine their quality and impurities; and pioneer metallurgical investigations were made on character samples to present their metallurgical problems. Some factors influencing past and potential western iron markets are discussed. The location, features, qualities, extent, and potential of iron occurrences and some associative resources--limestone and dolomite, coal, petroleum and natural gas, power, and water are discussed. The most abundant iron minerals are magnetite and hematite. The higher grade deposits are extensive contact-metamorphic or pyrometasomatic replacements of calcareous Paleozoic to Proterozoic rocks associated with intrusives. Large low-grade deposits of great potential are present as Precambrian taconite, semitaconite-, and jaspilite-like iron formations of magnetite-hematite. Iron occurs also as low-grade concentrations of magnetite in extensive alluvial deposits. Nonferrous metallurgical slags, nearly 100 million tons, are considered a potential source of iron. Various accessory elements are associated with the iron minerals and these pose metallurgical and economic problems.

Jan 1, 1964