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By James R. Miller

Recent experience over extensive areas of the Basin and Range Province has demonstrated the importance of the basin's (valley's) geology and geomorphology in locating large quantities of good-quality aggregate. First, a geologic map depicting basic geomorphic-geologic units in a valley is made in the office from aerial photography. Next, derivative maps are made from geologic maps and field-derived information such as parent rock type, source area and depositional environment, relationship to adjacent deposits, and Quaternary geologic history. Studying the derivative maps leads to selection of test sites for potential deposits of high-quality aggregates. Subsequent field studies provide more detailed information about geologic processes and samples for laboratory testing. Combining all information allows the characterization of aggregate potential of very large areas. Favorable areas can be further tested. This phased approach has proven to be cost effective. The methodology used in mapping and characterizing basinfill deposits is applicable over much of the western United States. Map units were developed by focusing on the predominate geomorphic process, grain size, cementation, and relative age. The resulting functional map units are of use to engineers and planners. This study led to many conclusions, including the fact that the best quality basinfill aggregates are found in selected alluvial fan deposits and Pleistocene lakeshore deposits. The best quality aggregates are derived from Paleozoic carbonate and quartzitic parent materials that can also provide high-quality crushed-rock aggregates.

Jan 1, 1987

By Rod Heath

The Saskatchewan industry has the advantages of an ore body of a size and consistency unmatched anywhere else in the world, and large, efficient mines with production costs that compare favourably with those in other countries. On the minus side, Saskatchewan is remote from most major markets, and producers face a distribution challenge to reach the offshore markets which is the main focus of this presentation. One of the characteristics of the world potash business is that all of the major sources of production are located in the developed areas of the world, while there is no significant production in any of the highly populated developing countries. The major potash producers are located in Canada and the United States, in West Germany, France, Spain and the U.K., in Russia and East Germany, and in Israel and Jordan. There is currently no significant production in any of the countries in Asia (with the exception of Jordan where a plant is currently in the start-up phase), Africa, Latin America or Oceania, and all of these areas must, therefore, import a11 of their potash requirements from the producing countries.

Jan 1, 1985

By R. L. Teseneer

Pyrite samples from twenty-one locations in the North Carolina Slate Belt were analyzed for cobalt, gold, mercury, and nickel by atomic absorption spectrophotometry. The geographic distribution of relatively high values of certain trace elements in pyrite suggests that, in addition to gold, cobalt and nickel metallogenetic provinces are possible in the slate belt. Northwest trends of province boundaries may be genetically related to subsurface features rather than to surface geology. Within province boundaries gold and nickel exploration programs should be concentrated in areas containing intermediate to mafic tuffs, while cobalt may be more concentrated in argillites and phyllites.

Jan 1, 1979

By Alan J. Michaels

The paper addresses the problem of the high costs of accidents ad how AMAX Inc. - a diversified natural resources company - has managed to control its losses through a tri-thrusted approach of: (1) management commitment, (2) methods of implementation that are tailored to each division or local unit, and (3) a reward system for outstanding performance. Specific attention is focused on the Corporate Loss Prevention Department's "10 Point Program for Loss Prevention Management".

Jan 1, 1981

By Thomas Pollard

It is truly remarkable how the image of longwall as a method of mining has changed. Between 1920 and 19609 viewed on a world wide basis, longwall was regarded as a' system for difficult and deep conditions and associated with intensive labour extraction. Today the world looks on longwall in the hope that it can produce the next really big break through in productivity, Three correlated machinery developments have made this possible, but it is not only the machinery developments, interesting though these be in themselves, but together with developments in control systems of these machines that longwall now looks so much more attractive, The machinery concerned is, of courses:- 1. The Anderton Shearer Loader - A miner that takes a narrow strip off the, face at rates acceptable to modern mining engineers. 2. An Armoured Flexible, Conveyor which can be kept in close contact with the face and still convey coal as it is snaked over to the faces 3. Powered support systems which can be mechanised and controlled with reliability at any distance from the individual support itself.

Jan 1, 1964

By Yuemin Zhao, Daniel Tao, Rick Honaker, Maoming Fan

"Froth flotation is the most widely used method of separating fine coal, especially coal with coking properties. However, froth flotation is not efficient for treating ultrafine coal and coarse coal particles. Our previous fundamental test results demonstrated that cavitation-generated nanobubbles around 700 nm in diameter can significantly improve coal and phosphate flotation performance over a wide particle size range. In this study, the effect of nanobubbles on the flotation performance of different particle size fractions of coal was investigated using a bank of 10-L flotation cells, a specially designed 50-mm inside diameter column and a 152-mm inside diameter column. It was found that nanobubbles that were either directly formed on or subsequently attached to the surface of coal particles during the froth flotation process improved flotation efficiency. The use of nanobubbles in a bank of mechanical cells flotation and column flotation significantly increased the flotation recovery at a given product grade. Nanobubbles increased the flotation rate constants of different coal particle sizes. The presence of nanobubbles in flotation slurry could extend the lower and the upper particle size limits for effective coal flotation.IntroductionFor minus 0.6 mm fine coal or minus 0.15 mm ultrafine coal particles, froth flotation is known to be the most efficient and the most cost-effective separation technique. However, flotation efficiency decreases sharply with ultrafine and relatively coarse coal particles. Studies have shown that the low flotation efficiency of ultrafine particles is mainly due to the low probability of bubble-particle collision (Yoon et al., 1989; Ralston and Dukhin, 1999). Enhanced flotation of fine and ultrafine coal can be achieved by increasing collision and attachment probabilities.The top size of particles that can be recovered by flotation depends on the combination of mineral properties and flotation devices. Turbulence in flotation devices is an important factor that affects the stability of bubble-particle aggregates. Even in the flotation of fine particles, bubble-particle detachment can significantly influence the kinetics of flotation taking place in mechanical cells, which provide intensive turbulent agitation (Deglon et al., 1999). Coarse particle flotation is more difficult, because increased agitation is required to maintain particles in suspension and coarse particles are more likely to detach under turbulent conditions (Mankosa and Kohmuench, 2002; Soto and Barbery, 1991). More efficient attachment of particles and improved flotation rate has been observed when tiny bubbles coexist with conventional-sized flotation bubbles (Attalla et al., 2000; Tao et al., 2010; Fan et al., 2010a, b, c, d; Fan et al., 2012)."

Jan 1, 2015

By Eric Hansen, Todd Wanless, Chris Mueller, Shannon Dunne, Scott Elmer

Between 2010 and 2018, Houston added more than 1 Million residents; the third largest rate of growth in the nation. With growth, the region faces new challenges with water supply, capacity of its wastewater system, and regional drainage. While tunnel construction has been limited in Houston since the Clean Water Program of 1990s, it is about to see a resurgence to improve water supply reliability and to reduce flood risks and sanitary sewer overflows. This paper examines the challenges with “going deep” below the built urban environment and related to high ground water; stiff, fissured clays; flowing silts and sands; faults; hazardous materials; and abandoned well fields.

Jun 13, 2021

By Leslie Thompson, Randy Hiebert, Marietta Canty

A paper is presented in which an innovative biological process is described for the treatment of cyanide-, metals-, and nitrate-contaminated mine process water. The technology is capable of detoxifying cyanide and nitrate and immobilizing metals in wastewater from agitation cyanide leaching as well as heap leaching. A pilot-scale demonstration is described in which a pilot plant was constructed to detoxify cyanide and immobilize several metals from a mine process wastestream at a mine in Nevada. The demonstration was performed jointly under the Mine Waste Technology Program (MWTP), which is funded by the U.S. Environmental Protection Agency (EPA) and is jointly administered by the U.S. Department of Energy's (DOE) Western Environmental Technology Office (WETO) and the Superfund Innovative Technology Evaluation (SITE) Demonstration Program under Interagency Agreement Number DW89938513-01-0. MSE Technology Applications, Inc. (MSE) located in Butte, Montana, was the contractor responsible for conducting the project, and Pintail Systems Inc. of Aurora, Colorado, was the technology provider. The pilot-scale unit was field tested at the Echo Bay McCoy/Cove Mine southwest of Battle Mountain, Nevada. The biotreatment process was con­sidered to be very successful in detoxifying cyanide from the mine process water. The process was also determined to be very effective in removing metals. The pH was consistently neutral­ized and nitrates were successfully removed in the mine process water. As a result of conducting these pilot-scale tests, the biotreatment process was concluded to offer an innovative, cost­effective alternative for the treatment of mining wastewaters.

Jan 1, 1998

By Charles M. Brinckerhoff

Everyone -- especially the engineer -- is aware of the great technological and social changes taking place in our world today, We realize that changes have been taking place since man's beginnings on earth, but the element we now face is the speed of change, rather than change itself. Developments in medicine, in transportation, in space exploration, in global communications, and in many other fields, are constantly being made known. These developments are affecting the lives of each of us, although some may appear remote and unrelated to us as individuals. New developments, almost on a daily basis, affect our work as well as our social, religious and educational lives. The effects are immediate and permanent.

Jan 1, 1967

By I. Edgar Odom

Hectorite is a rare magnesium-lithium clay mineral that occurs at many places in the McDermitt caldera of Nevada-Oregon. Commercial development of several high purity deposits began in 1986. The hectorite that was precipitated in a lake environment formed after the collapse of the McDermitt caldera. Hectorite beds and lenses are associated with volcanic sediments, limestones, dolomites, zeolites and locally sandy bentonites. The high purity deposits appear to be associated with hydrothermal areas. The hectorite consists of extremely small, flake-shaped crystals. Calcium (Ca) is the predominant exchangeable ion. Its color ranges from white to light green. Commercial uses include high-brightness, magnesium-aluminum-silicate (MAS) products, organophilic clays, pulp retention and ceramics. The MAS is used as a suspending agent, binder, stabilizer and thixotrope in aqueous solutions for cosmetics, household cleaners, pharmaceuticals and miscellaneous industrial applications. Hectorite-based organophilic clays are used in printing inks and paints. The McDermitt caldera complex is located astride the Nevada-Oregon boundary west of the town of McDermitt, NV (Fig. 1). The structural complex is elliptical in shape, extending about 43 km (27 miles) north-south and 34 km (21 miles) east-west. This area was the site of extensive volcanism during the Miocene (24 to 18 million years). The complex consists of five overlapping calderas with the oldest at the south end of the complex (Rytuba et al., 1979). Each of the vent areas collapsed and is marked by a ring fracture zone. The ring fractures around the outer boundary of the caldera complex are shown in [Fig.1].

Jan 1, 1992

By B. C. Haimson

The Committee on Rapid Excavation of the National Research Council has recognized in its 1968 report the need for "improvement of rock-mechanics techniques for measuring subsurface stress field in deep boreholes and for determining stress distribution in walls of underground excavations". The technique recommended in this paper as being most suitable for both deep hole and tunnel wall stress determination is Hydraulic Fracturing. Using this method stresses are calculated directly from the fluid pressures necessary to initiate and extend a fracture away from a borehole. Stress determination by hydraulic fracturing is rather insensitive to inhomogeneity or anisotropy, is not limited in depth except by the length of the hole, requires simple equipment which is commercially available, and can be carried out by unskilled personnel. The method has been worked out theoretically and extensively tested and verified in the laboratory. A number of field tests in deep holes ranging from 300 to 6300 ft have yielded surprisingly good results. Preliminary underground tests have been very encouraging and most recent measurements in a tunnel complex at the Nevada Test Site yielded stresses that were both consistent and reasonable when compared with the expected directionsand magnitudes. It is recommended that hydraulic fracturing be considered as a method of in-situ stress measurement both in the pre-excavation stage of design and during tunneling.

Jan 1, 1974

By Philip A. Mattson

INTRODUCTION Engineers involved with rock mechanics know the importance of discontinuities within a rock mass and their effect on its behavior when subjected to loads from structures or construction excavation activities. Various geophysical tools have been developed to provide comparative information on subsurface conditions, such as electrical resistivity, assorted seismic test methods, acoustic tests, etc. While these investigative means have proved invaluable in numerous situations, especially those where site alternatives are being evaluated, they shed little light on the difficult problem of quantifying the rock strength. For that purpose, a laboratory test program of samples obtained in the field is usually undertaken, often in conjunction with a variety of in-situ tests. While standard samples provide sufficient information on the rock properties, questions on the macro-structure of joints, faults, fissures, and their infillings often go unanswered. Presently, attempts are being made to incorporate into rock sampling technology new techniques which are directed towards providing better information on the incidense and orientation of discontinuities. One such device incorporates a scribe knife within the core barrel which scores the sample lengthwise as it is cored. The orientation of the scribe is known, thereby relating the bedding, planes, fractures, etc. to a spatial framework. A second approach, called the Integral Sampling Method, is the subject of this paper. Stated briefly, this method utilizes a grout injection to bond fractured rock to a steel reinforcing bar at the center of the coring. The bar is intended to act as a

Jan 1, 1979

By S. K. Nicol

The results of column flotation tests conducted on a bulk sample of ultrafines discarded from the fine coal desliming cyclones at the Riverside coal preparation plant of Theiss Dampier Mitsui Coal Limited are presented. A 9% ash concentrate was obtained from a 51% ash ultrafine feed at 75-80% recovery of combustibles in a single stage of column flotation. From this result it is predicted that installation of column flotation at Riverside would lead to the annual recovery of additional coal worth $US5.1M. The operating conditions for coal and copper column flotation are compared and some differences which may result in a variation in column design are noted.

Jan 1, 1987

By Michael Davis

In the fairly recent past, with a history of cheap and abundant energy, it has been possible to predict with reasonable confidence that world energy demand would continue to double about every 15 years. Those who attempted to forecast the role of nuclear energy in future electricity generation could also start with the fairly safe assumption that electricity demand would increase even faster : with a doubling in demand about every 10 years. To estimate the likely future world demand for uranium it was then necessary to introduce a number of other assumptions including the rate of penetration of nuclear energy, the timing and the specific fuel requirements. This series of assumptions naturally compounded the uncertainty, but, remarkably, usually led to future uranium demands being overestimated. Such a bias which has almost always been observed in predictions made over the past 20 years has increasingly made uranium producers sceptical when expected to match the forecast demand with increased production capacity and supporting reserves. This scepticism has, of course, been reinforced by the persistence so far of a buyers' market in uranium throughout the entire period of emergence of commercial nuclear electricity generation.

Jan 1, 1974

By Thys B. Johnson

This paper presents a new algorithm for solving the Controlled Flow Mine Ventilation Problem in an optimal manner - minimum power consumption. The use of booster fans and restrictions on the locations of ventilation regulators are dealt with in a straightforward manner. This new approach is based on a common Operations Research algorithm for which there are many fast computer programs available.

Jan 1, 1982

By Robert M. Lewis

Chemically, mica is a complex silicate of sodium, potassium and aluminum. There are no important uses of mica where the chemical analysis is important, except that in some uses of ground mica, the content of iron oxide present as an impurity must be kept to a very low limit. Muscovite mica is frequently found containing black and red "stain" as a homogeneous part of the books or sheets. In most cases this stain or impurity is magnetite or hematite. Some mica contains impurities deposited by infiltration. This is commonly a red stain, less often brown or white. The best mica is free from all such impurities, and the greater their content, the less value does the mica have.(1) It is because of these undesirable impurities that a large segment of the fine ground mica industry relies on weathered pegmatites and alaskite ores as a source of raw material. The mica concentrates obtained from these ores are relatively clean and require moderate beneficiation to meet color and density specifications. One need only to observe the stained and decrepitated condition of the mica recovered from mica schist to appreciate the challenge that processing this material presents. Despite these adversities there are several advantages to be gained by mining and processing mica schist ores. The mica content of these ores are considerably higher than the pegmatites and alaskite ores now being mined, often containing in excess of forty percent mica. This-higher grade mica feed should promote a lower mining and milling cost with its resulting competative advantage. With more rigid government

Jan 1, 1969

By Mike Rhodes, Paul Miller, John W. Neale, Vishal Deeplaul, Barrie Hancock, Tony Pinches

The Beaconsfield underground gold mine is one of only a few new Australian gold projects to come into operation in the current climate of low gold prices. Up to 200,000 tonnes per annum of Tasmania Reef ore will be mined and processed over a minimum eight-year life to a depth of 900 metres below surface. The Tasmania Reef is a gold-bearing quartz-carbonate-sulphide vein occupying an old fault structure which transgresses a series of sedimentary beds. The sulphides are predominantly pyrite with lesser arsenopyrite, and also minor copper as chalcopyrite. Drilling to date below this level clearly indicates that the high-grade orebody is open at depth and that the mine life should be extended significantly over time. Since redevelopment of Beaconsfield mine began in the 1980's, extensive exploration has identified a resource of 1.5 million tonnes within a 450 vertical metre zone beneath the old workings, which extended more than 450 metres below the surface. Installation of an 800 litre per second capacity pump station 180 metres below the surface has been critical in overcoming one of the major hurdles experienced during previous operations in the early 1900's. A multi-stage development program, designed to bring the mine into full production, and incorporating construction of the on-site gold treatment plant incorporating bacterial oxidation, has now been completed. Prior to execution of a detailed engineering design of the Mintek-BacTech bacterial oxidation process, a programme of bacterial oxidation testwork was completed to provide a basis for fixing the process design criteria. A flow diagram of the Beaconsfield treatment plant is shown in Figure l. It comprises:

Jan 1, 2000

By J. J. Schwoebel

Resource Enterprises, Inc. (REI) is exploiting the coalbed gas resource by working in unison with active underground mining operations. At REI?s pilot project at the Soldier Canyon Mine, Carbon County, Utah, REI has drilled nearly 15,250 m of horizontal in- seam and slant boreholes during the initial two years of drilling activity. Produced gas has been sold to a natural gas transmission company on a continuous basis since mid 1983.

Jan 1, 1986

By B. M. Kunar, C. S. N. Murthy, B. Rao K

Rock particle size has a very important significance in the mining industry, starting from blasting till the mineral processing. The present study was carried out to understand the particle size distribution in various sieves after conducting the ball milling process. The time of the grinding process was varied at different intervals. It was observed that 80% of the particles of both granite and marble rock samples passed through the 4800 μm sieve when subjected to grinding time of 40 minutes. Also, it was observed the number of particles that were retained in the smallest sieve of <75 μm was higher in the case of granite sample when compared to a marble sample. INTRODUCTION India is a major exporter of granite and marble stones. The major use of marbles and granites are constructing walls and floors. There are several machining processes that are applied before it is used as floors and walls. During this process, wastes are produced these wastes are used in various ways. These include use of powders for clay products (Segadães, Carvalho, & Acchar, 2005), as an additive in cement production (Aruntaş, Gürü, Dayi, & Tekin, 2010), to enhance the properties of brick ceramics (Saboya, Xavier, & Alexandre, 2007), in constructing bricks (Bilgin et al., 2012) and as an additive in concretes (Aliabdo, Abd Elmoaty, & Auda, 2014). Usually, the powder form of marble and granites are used as an additive in the above-mentioned applications. Powders of marble and granite are obtained through the grinding process. One such process of grinding is the ball milling process. In the ball milling process, a quantity of samples along with the charge quantity consisting of steel ball is subjected to a grinding process within a closed chamber as shown in Fig. 1. An even particle size can be obtained through sieving the material after subjecting it to grinding. The present study is planned to understand the particle size distribution in various sieves due to varying time and charge quantity in the experiment. Only time was varied to understand the amount of particle distribution in the case of granite and marble rock samples and a comparison is drawn. A statistical model was developed for marble rock specimen considering the data obtained by varying time and charge quantity in the ball mill experiment.

Jan 1, 2019

By Joseph M. Denk, John N. Baran, William J. Francart

Filling or sealing shafts of underground coal mines is required when the mine is declared inactive by the operator, permanently closed or abandoned for a period of time greater than 90 days. Although shaft filling requires the use of incombustible materials for the first fifty feet of the shaft, a sparking potential may exist which has been reported to be the cause in at least one shaft-filling explosion. This paper outlines the method used at the explosion site to monitor mine gases within the shaft to assure the safety of the workers involved in the remainder of the shaft-filling operations. Gases which were monitored include methane, oxygen, carbon monoxide and carbon dioxide. Continuous sampling was conducted twenty-four hours per day to determine the methane liberation and accumulation of gases within the shaft. Once gas concentrations were evaluated, the need for ventilation in the shaft was obvious because methane accumulations within the shaft were in the explosive range. Several methods to ventilate the shaft were explored. The most practical seemed to be the dilution of gas concentrations with compressed air to inject a quantity of fresh air into the shaft. But, when the compressed air was stopped, a buildup of an explosive mixture reoccurred. The pattern of gas accumulation was then studied to find the correct combination of ventilation and shaft-filling time periods which would a1 low for the greatest reduction of the potential for an explosion. Gas concentration sampling continued during the remainder of shaft-filling operations at this shaft and four others at the same mine. In conclusion, this paper illustrates some of the problems which are often overlooked in a shaft-filling operation. If addressed, the work can be done in a safe and feasible manner.

Jan 1, 1987