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By A. S. Speirs

Over the last few years, the never-ending search for mineral wealth has taken the exploration efforts of Canadian mining companies further and further into the High Arctic and isolated locations where regularly scheduled transportation and communication facilities are nonexistent. Names such as Black Angel, Nanisivik, Asbestos Hill, New Quebec Raglan, Rabbit Lake, and Arvik are today frequently mentioned in mining publications. Twenty years ago, mining in these locations was unheard of, mainly due to logistic problems. However, improvements in the design and use of helicopters, STOL aircraft, and icebreakers in northern areas have helped to overcome these problems, making these locations more attractive to mining companies. Since 1969, when Redpath completed its first Arctic project at Texas Gulf's Scrathcona Sound property on the northern tip of Baffin Island, Redpath has been actively involved in contracting and engineering projects in three general areas: the High Arctic, Ungava and Greenland. A map showing some of these projects is shown in Figure 1. In these areas, permafrost conditions exist from a depth of 274 metres in Ungava to a depth of approximately 610 metres in the Little Cornwallis Island area, with rock temperatures ranging from -5°C to -13°C. Outside temperatures range from a low of -50°C in the winter to a high of 21°C in the summer. High winds in the winter result in wind chill factors lower than -73°C

Jan 1, 1980

By Arthur S. Radtke

The structural setting of disseminated-replacement gold deposits of the Carlin-type and other aspects of their genesis are closely related to events which took place during the evolution of the Basin and Range province. The deposits formed as a result. of chemical and physical processes which took place at shallow depths in the roots of hot spring systems at moderate temperatures (about 200°C) and low pressures (about 25 bars) (Radtke and Dickson, 1974). Locations of Carlin-type gold deposits in the Basin and Range province are shown in Figure 1. Most of the block-faulted mountain ranges in the Great Basin formed by tectonic activity that happened since Miocene time, although faulting in some places probably began in Eocene to Oligocene time (Hamilton and Myers, 1966). The Carlin-type deposits are spatially related to Basin and Range-type faults: Many deposits, such as Getchell, Pinson, Preble, and Cortez, occur along the flanks of ranges, while other deposits, including Carlin (Radtke, 1974) occur within the ranges in areas characterized by crosscutting and intersecting high-angle or Basin and Range-type faults. The association of the ore deposits with Basin and Range-type faults is evidence that ore deposition is young, Miocene or later. The steep, high-angle faults played three roles: first, they provided deep channels for upward-flowing solutions; second, in preparing the rocks for fluid penetration by brecciation and general rock dislocation; and third, they moved sedimentary carbonate rocks, favorable for ore deposition, from deep levels to near-surface positions where the physico-chemical conditions were more suitable for the deposition of ore.

Jan 1, 1976

By D. L. Monroe

Technical service is assuming an increasingly important role in the sale of asbestos fibre,, Manufacturers are examining raw materials more closely than ever before in order to, obtain the most efficient usage in their processes. Asbestos is one of the more difficult materials to evaluate and consequently has been are of the last to be subjected to evaluation. The main problem encountered in the evaluation of asbestos fibre is that minor differences in grade and texture are not shown up by chemical analysis, and are identified only by specialized physical analyses or actual production use. However, such minor differences become more critical as manufacturing processes are made more efficient, and many purchasing agents and plant chemists are applying a closer scrutiny to their supply of raw asbestos fibre. Many processes have been formulated around grades and qualities of asbestos fibre, which were standard some time ago, but which may now be subject to modification and improvement.

Jan 1, 1959

By . A. J. Erickson

The Park City District, one of three major mining districts in Utah, is located approximately 20 miles southeast of Salt Lake City on the eastern slope of the Wasatch Mountains. The district has been in near continuous production since 1869. Production has been sustained from exceptionally long bedded replacement ore bodies in the Thaynes, Park City, and Humbug formations and also from several major veins. District production is summarized below. TABLE NO. 1 Park City District, Total Production, 1869 thru 1968 (Source r Various Company Records) [ ]

Jan 1, 1970

By Duk-Won Park

The stability problems of back- filled spoil banks became more important since the Federal Surface Mining Control and Reclamation Act of 1977 was enacted. The material properties of spoil banks were categorized as the first part of the study and spoil slope stability was evaluated using computer programs as a second part. Emphasis was placed on the effects of natural barriers, which is required in the federal law.

Jan 1, 1982

By K. K. Wu

In some cases, coal barrier pillars must be relied on to withstand high hydrostatic pressures in order to prevent inundation of active mine workings. Such barriers are particularly important in areas, such as parts of West Virginia, where much of the future mining is down dip of mines which have been abandoned, or are currently being worked. Also, where multiple seam mining is conducted, a barrier pillar in one mine may be critical to safety in a mine in a lower seam. MSHA's Coal Mine Safety and Health district offices and the Mine Waste and Geotechnical Engineering Branch of the Pittsburgh Technical Support Center, have recently been involved in the study of barrier pillars in Kentucky, Virginia, West Virginia, Ohio and Oklahoma. In this paper, the factors involved in determining the required width of pillar are discussed, past practices for sizing barriers are reviewed, and related current Federal regulations are examined. In addition, the results of laboratory testing of bottom rock are presented.

Jan 1, 1980

By Henry R. Tiedemann, Eugene H. Skinner, George E. Wickham

Improving the state-of-the-art of tunneling is a continuing challenge to those involved in underground construction. New methods and procedures are usually evolved over a relatively long period of time as compared to advancements in other types of construction. To a large extent this is probably due to the fact that tunneling deals with a material or medium - the rock structure - whose physical properties are not only extremely varied, but in many instances virtually unknown until time of penetration. This hovering of the unknown tends to make "non believers" of many and at best leads to a general reluctancy of accepting new ideas or procedures. The situation is further complicated by: 1) discrepancies in terminology and respective meanings as used by different disciplines to describe, define or evaluate pertinent factors and their relative effect on the tunneling process and 2) the fact that no two tunneling situations are identical with respect to either geological conditions or construction and contractual requirements. In spite of the above there have been many successfully completed tunnels which make it apparent that both the technical and practical expertise needed to develop or project improvements is available within the industry. It is with this in mind that the RSR concept was developed. BACKGROUND This paper presents the findings and results obtained from contin-

Jan 1, 1974

By Frank W. Bowdish

Studies of sulfidization and flotation of chrysocolla involving the use of pH and sulfide ion instruments, a Zeta meter, microflotation techniques, and sensitive determinations of adsorbed sulfur have given new insight into the mechanism of the process. Factors that affect the recovery of sulfidized chrysocolla by flotation appear to be the pH at which it is sulfidized, and certain alterations of the surface that occur during aging after sulfidization. Such aging results in increased recoveries. The surface charge, as measured by electrophoretic mobility, of chrysocolla shows an unexpected negative increase as pH values are changed from 6.0 to about 4.5, and this appears to be correlated with increasing sulfur adsorption and flotation recovery over the same or even wider pH ranges.

Jan 1, 1970

By David A. Summers

Historically, the presence of methane has been a problem, mainly in and around the working areas of active coal mines, and only in these area has drainage been considered. Drainage, where practical, has been achieved through the drilling of holes forward into the coal and the surrounding strata from the working area. These holes generally have been short in length, although where methane drain- age operations around a longwall face have been undertaken, the holes have had to be longer in order to adequately drain from the center of the face into the access gate roads. In recent years, attempts have been made to degasify the coal seams in advance of mining, without disruption of the mining cycle. This is done by drilling much longer horizontal holes through the coal in advance of the working area. Under the aegis of the Federal Government, methods have also been developed for draining seams of coal of their methane content in advance of mining, but from shafts sunk from the surface, without using the active area of the mine as the location for the drill holes.

Jan 1, 1979

By Ande&apos, Bengt n

The first Model 480 SALA-HGMS R carousel high gradient magnetic separator was recently manufactured (Figure 1). The carousel's design was based upon the high gradient magnetic separation technology developed and owned by Sala Magnetics Incorporated, Cambridge, Massachusetts. After a short (approximately 300 hours) in-house mechanical and electrical test and break-in period, the carousel was ready for a long term demonstration test. This paper describes the demonstration plant and operational performance of the Model 480 HGMS treating a low grade iron ore tailings. A location convenient to Sala International's main office in Sala, Sweden was desirable because Sala engineers and technicians were to operate the demonstration plant. The Strassa iron ore mine in central Sweden was chosen because it fit most of the criteria that was important for a good demonstration site. The Strassa mine is part of the state owned Svenskt Stal AB. The mine produces about 320,000 tons of iron concentrate per year consisting of 200,000 tons of magnitite concentrate and 120,000 tons of hematite concentrate.

Jan 1, 1980

By John S. Burton

Mineral policy in Canada has been in a state of transition and change over the past several years. 1976 has witnessed some settling of troubled waters and the pattern of the currents of change is becoming more clear. The provinces play a key role in this process and have provided much of the thrust for new initiatives. On the other hand, the federal government in Canada in recent years has taken a much more active interest in mineral affairs than previously and has asserted its powers on a number of key policy questions. Some of the initiatives from the two levels of government in Canada have come into conflict with each other and, thus, contributed materially to a state of affairs that includes change, uncertainty and conflict.

Jan 1, 1976

By M. A. Bouchat

The Kipushi deposit, where the Prince Leopold Mine has been installed, belongs to Union Miniere du Haut-Katanga and is located in the Belgian Congo, 20 miles SW of Elisabethville, at the vicinity of the Northern Rodhesian Border. The deposit is of the hydrothermal metasomatic vein-type; mineralisation took place, through the limestone of the, lower Kundelungu. This is a special fea¬ture of the deposit, compared to the other copper deposits of the neighbourhood, both in the. Belgian Congo and in Rhodesia. Actually, the primary mineralisation of these other deposits; is directly related to the stratigraphic systems: schistous dolomitic in the Belgian Congo and Roan in Rhodesia. Both facies are older than the Kundelungu and separated from this formation by a tectonic cataclysm. The valuable elements occuring at Kipushi are principally copper; and zinc. The deposit also contains smaller quantities of lead, precious metals and other elements including germanium.

Jan 1, 1960

By T. D. Oulton

The only known attapulgite clay deposits of any considerable extent and purity in the United States are roughly bisected by the Georgia. Florida state line between Decatur County, southwest Georgia, and Gadsden County, northwest Florida. Although attapulgite clay occurrences both farther East and South are known and have been mined to some extent in the past, at the present time it can be said that substantially: all of the commercial attapulgite clay mining and pro¬cessing is concentrated in a roughly rectangular area some 25 miles long by 15 miles wide,, in the general region of Attapulgus, Georgia, and of Quincy and Havana, Florida. Within this area are located the clay processing plants of the four major producers as well as most, if not all, of the currently active mining operations. The approximate location of the plants and of some of the open mines are shown in the local area map, Figure No. 1, for the purpose of orientation only.

Jan 1, 1965

By John A. DesLauriers, Hans J. Broennimann

INTRODUCTION The early record of tunnel excavating machines in hard rock tunneling has not been one to particularly brag about. We have all heard the stories of major difficulties when trying to break hard rock with machines at promised advance rates of several times that of conventional drill and blast. Unfortunately, sometimes this has not happened. It has been through this trial of the past generations disappointments that today's TBM's have evolved to their present high level of performance in a wide range of ground conditions. Today's machines offer much increased reliability and durability. This translates into high availability to the tunnel contractor. Although there still are occasional disappointments being reported, the state of the art is that reliable and predictable machine excavation of rock now is both a reality and well founded expectation. The most recent editions of Atlas Copco's MINI/MIDI Fullfacer, we feel, make a strong contribution to the reliable performance of todays TBM's---especially in small-size rock tunnels. This report will, 1.) explain the equipment and effect of rock both on the cutting technique and machine performance; 2.) list advantages of the non-circular shape, during and after construction; 3.) list applications in civil and mining industries; 4.) discuss North American experiences, performance and costs; 5.) list advantages over drill and blast and; 6.) discuss briefly lease arrangements.

Jan 1, 1979

By E. A. Rychkun

With the aid of modern computer automation, certain mathematical techniques are easily adapted to geophysical, geochemical and geological data analysis. First and second derivative filtering (or transformation) of raw data, in many cases, gives a better indication of anomalous conditions than conventional methods of analysis. The calculations involved, which are tedious manually, are simple, accurate and fast with the assistance of Fourier analysis and modern computers.

Jan 1, 1968

By Keith A. Heasley

The objective of this paper is to back-analyze the August 6th ,2007 collapse at the Crandall Canyon Mine in order to better understand the geometric and geo- mechanical factors which contributed to that collapse. In this work, the LaModel boundary-element program along with the best available information is used for the back- analysis. To initiate the analysis, a six step base model of the mining in he Main West area was developed. This base model included a step for each of the critical stages in the mining of this area. Next, calibrated values for the critical input parameters: rock mass stiffness, gob stiffness and coal strength, were developed and optimized based on the best available information. Finally, the model was used to simulate the final mining scenario. As a result of this back analysis , a number of conclusions can be made concerning the mine design and the August 6th collapse: 1) Overall, the area was primed for a massive pillar collapse because of the large area of equal size pillars, 2) The abutment stress from the active retreat sections and the adjacent longwall panels were significant contributors to the collapse, 3) From the modeling alone, it is not clear exactly what triggered the August collapse, although the active mining is a reasonable assumption.

Jan 1, 2012

By J. L. Vanderbeek

The SAG milling of ores with markedly variable grinding rates presents definite process control challenges. Decisions must be made regarding the selection of the most appropriate combination of mill volumetric load level, percent solids, and mill speed for the combination of ore types being processed at the moment. An investigation was performed concerning the effects of these parameters. General results are presented.

Jan 1, 1985

By Hubert Erik Sherer

Determination of the best time to replace an aging unit of equipment is a recurring problem which is common to essentially all surface and underground mining operations. Virtually all mining equipment is subject to wear and the resulting deterioration that increases with equipment life. This mechanical deterioration results in lower availability and, thus, decreasing, production. Due to decreasing production and increasing repair costs, there is an optimum age at which the replacement of a given equipment unit with a new unit will result in the lowest cost per unit of production for the equipment operation in question (Figure 1). Determination of this optimum replacement age is further complicated by factors such as: possible overhaul alternatives, fleet replacement and expansion alternatives, remaining life of the mine, and technological improvements in the potential replacement or differences in the production capacities of these replacements. Determination of the optimum time to replace an equipment unit becomes more critical each successive year due to the rising capital costs of new equipment versus maintaining old equipment. An incorrect choice of the replacement age for an equipment unit can result in excessive costs to the mining operation. If a unit is replaced too early, the capital cost of the unit is not fully utilized; conversely, replacing a unit too late results in excessive maintenance costs and low production. The economic life of a piece of equipment is the equipment age that results in the lowest total discounted cost per unit of production for that piece of equipment, not considering the cost of future replacements. The economic life of a piece of equipment is usually shorter than the physical life, the maximum age at which a machine is capable of doing useful work. The optimum replacement age for a piece of mining equipment may vary from the economic life of that equipment due to the remaining life of the mine, fleet considerations, costs associated with potential replacement machines, and capital rationing constraints. For example, the equipment life of the current machine that may result in the lowest cost per unit of production might be 10 years; however, when the timing of the future replacement costs are entered into the calculation, a different life for the current machine might result in the lowest total cost per unit produced for the remaining life of the mine.

Jan 1, 1982

By Prakash M. . P. E. Donde

1. INTRODUCTION The Washington Metropolitan Area Transit Authority (WMATA) has often taken a leading role in introducing innovative construction technologies to build its transit system. Most recently, Contract Section E-5a, which included Fort Totten Station and Tunnels was constructed utilizing the New Austrian Tunneling Method (NATM) in soft ground. Along with the station and tunnels, two permanent shafts were also constructed in soft ground employing the NATM technique. This project is located within the District of Columbia on the Greenbelt Route. The subject of this paper is to discuss the unique method of construction of these two shafts, and explore the benefits of applying the NATM technique to the construction of deep shafts. The design of the shafts was performed jointly by Jenny Engineering Corporation of Springfield, New Jersey, and Mayreder Consult of Linz, Austria. The designers also provided construction support services and a resident NATM expert at the site during construction. The construction of the project started in April 1988 by a joint venture of Mergentime Corporation and H. T. Construction, a subsidiary of Hochtief Company from Germany. This $48.7 million construction project has been completed. 2. SUBSURFACE CONDITIONS The two NATM shafts are located primarily in Cretaceous-age deposits that are over 100 million years old. These deposits are intermixed and lenticular in nature

Jan 1, 1993

By J. F. Kvitfkovich, R. L. Bate

Coal production in the Central Appalachian region has a long history, and it remains a major US coal-producing region. The coal industry consensus is that the region is in a state of decline as evidenced by the recent lower regional output. Are Central Appalachian coal reserves adequate for the region to continue as a major supplier of low sulfur coal? To answer that question, this paper focuses on the Central Appalachian coal reserve base estimates and production trends. Central Appalachian (CAPP) reserve evaluations face the difficulty that there are no publicly available databases that provide a thorough analysis of remaining CAPP reserves. Based on best available Energy Information Administration (EIA) data, a coal reserve estimate of 17.6 billion tons is developed. This estimate appears high according to industry perception. Recent United States Geological Survey (USGS), and other state agency coal reserve estimation projects are evaluated as alternative approaches to the re-serve estimation problem. Using the conclusions from these studies, the CAPP reserve base is estimated at 7.1 billion tons. Another perspective on the CAPP reserve base is provided by reserve holdings of major CAPP operating companies reported at 5.2 billion tons. A conceptual mining cost analysis indicates substantial price increases will be necessary to offset this deterioration in the economic viability of the reserve base.

Jan 1, 2004