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By Dennis C. Parker

The Porters Creek clay is mined for its absorbent properties. The formation is part of the Upper Mississippi embayment and is recognized in Alabama, Mississippi, Tennessee, Kentucky, Illinois, and southeast Missouri. Major minerals in order of abundance are Montmorillonite, Quartz, Illite, Kaolinite, and Chlorite. Mining consists of open pit operation utilizing track loaders or scraper. The clay is dried or hardened in rotary kilns and crushed to size by roll crushers. The clay granules are sized and air classified prior to storage for shipment or packaging. Granules are sold for pet absorbents, oil absorbents, anti-skid material, fertilizer, and pesticide carriers.

Jan 1, 1979

By R. Bernard

This paper will discuss innovative strategies that combine the capabilities of an Enterprise Asset Management (EAM) solution, sometimes referred to as a Computerized Maintenance Management System (CMMS) and E-Commerce solutions. Strategies discussed include solutions that minimizes the costs of operations through maximized equipment productivity and availability. Thusly, achieving the ultimate goal of keeping the cost per production unit as low as possible.

Jan 1, 2001

By J. Loredo

The region of Asturias, located in the northwest of Spain, has an extensive mining history; coal, gold, zinc, lead, copper, cobalt, mercury, iron, manganese, fluorspar and others have been extracted from the antiquity. In the Asturian Central Coal Basin, the closure of all open pit coal mines and their restoration, the progressive closure of underground coal mines that is happening from the 1980?s, and the restoration of spoil heaps, provides post mining lands for alternative uses. In relation to metallic mining, the abandonment of all mercury mines without restoration in the 1970´s, has left significant quantities of wastes and mining works. More than thirty years later most of them remain without restoration. In these sites the legacy of the historical mining activities is apparent in the form of shafts, galleries and transversals, old mining installations and spoil heaps. Mine wastes have eventually become important Hg and As pollution sources, resulting in a widespread contamination of the surrounding soils and surface waters. Abandoned mines of other metals such as copper, cobalt, iron, etc. and industrial minerals such as fluorspar, have also left a mining legacy to take into consideration. In this context of declining mining areas, some remedial options have been applied to specific areas resulting in alternative uses as pastures, agro-forestry, industry and socio-cultural activities.

Jan 1, 2008

By S. R. Clark

"INTRODUCTION Of all the natural resources being taxed by the needs of the modern world, perhaps the most important is the continually expanding demand for water resources. As water becomes scarcer, and increasingly important, new technologies are needed to find innovative ways to preserve this precious resource. In Chile, for example, the mining industry is investing billions of dollars to build desalination plants and pipelines; bringing ocean water as far as 200 kilometers inland to meet their demand and maintain operations. It is a full-blown crisis for that nation and a top priority for their government and economy. It has been reported that world water consumption will increase by 40 percent in the next 10 years, representing nearly exponential growth. In the U.S., as more and more communities continue to be built, more drain on the current water infrastructure is created. For 25 percent of people and operations that rely on water from aquifers, this source is being consumed at a rate that will create significant problems meeting the demand in as few as two generations.1 A PROACTIVE APPROACH When it comes to controlling dust at your operation, whether a landfill, a transfer station, a haul road or another ancillary area, what are the options? We know watering is not the answer, but at the same time, we need to prevent dust from flying to ensure a safe environment and keep our skies clear of pollution, for both regulatory requirements and neighbors. Creating a Dust Mitigation Program instead of looking to buy the first dust control product off the shelf is a first step to conserve water and, at the same time, maintain the operational demands and environmental standards for a given site. The program concept is straightforward enough. However, the process of effectively constructing and executing a program is quite involved. When undertaking a program, each manager needs to work with their team and their partners/vendors in analyzing the following elements: 1. Site Expectations—It is important to understand how to balance your internal standards with your regulatory requirements, as well as how to keep your neighbors satisfied. 2. Site Aggregate—Variations in native soil, such as clay content or gravel levels, greatly affect the approach that will yield the highest results. 3. Climate—Relative humidity and seasonal variations are critical to achieving predictable results through product choice, application frequency and timing. 4. Daily Traffic—The type and frequency of traffic is an essential variable for site management. 5. Environmental Responsibilities—If you have additional, specifically defined responsibilities, the approach to your site may vary. 6. Budget—While efficiency is the goal of any program, some sites will have more stringent restrictions than others. 7. Current Usage Rates—Document and understand where you’re starting from, both with water, supporting products, and maintenance so that effective measurement of results is possible."

Jan 1, 2018

By M. J. Lowe

National Institute for Occupational Safety and Health (NIOSH) studies show that 43.5% of surveyed coal preparation plant workers had noise exposures exceeding the Mine Safety and Health Administration Permissible Exposure Level. Sound levels around vibrating screens in these plants often exceed 90 dB(A). NIOSH is currently developing noise controls for horizontal vibrating screens. To characterize noise sources, NIOSH researchers performed sound pressure level (SPL) measurements on a vibrating screen at their Pittsburgh Research Laboratory. The results show that the entire screen contributes to noise below 1 kHz and the vibration mechanism housings are most significant above 1 kHz. Constrained layer damping (CLD) treatments and an enclosure were used to reduce mechanism housing noise. These were evaluated using sound power level measurements according to ISO 3744. The CLD treatments reduced the A-weighted sound power level by 3.1 dB in the 1 to 10 kHz one-third-octave bands. A panel-on-frame vibration mechanism enclosure using various types of panels further reduced the A-weighted sound power level from the CLD configuration in the 1 to 10 kHz one-third-octave bands by 3.7, 4.0, and 3.9 dB for aluminum, steel, and Dynalam panels, respectively. The combination yielded a 7 dB reduction from baseline in A-weighted sound power for the same frequency range.

Jan 1, 2010

A PDP 11/34 computer has been inter- faced to existing instrumentation in a 400 tph rod-mill/ball-mill grinding circuit and programed with a Kalman filter to estimate several unmeasured variables. A dynamic two-size- fraction model of the circuit is used to predict the complete state of the circuit including particle size distributions around the circuit, mass holdups and flowrates, the ball-mill grinding rate, water additions and cyclone parameters. Online measurements of sump level, slurry densities and product particle size are used to update the model values sequentially on a 20-second interval. This procedure results in optimal estimates of circuit variables given the relative reliability of measurements and the accuracy of the model.

Jan 1, 1983

By R. D. Williams

Several hydrometallurgical leach processes have been recently proposed for the recovery of copper from copper concentrates. These include the Cymet Process of Cypress Metallurgical Processes Corporation, the Arbiter Process of the Anaconda Company, and the Treadwell Process of Treadwell Engineering company(1). These processes and similar processes for recovery of other minerals, have several phenomenological similarities which make their quantitative description difficult at best. These include (a) the presence of more than one phase, (b) non-uniform mineralization of the feed concentrate, (c) surface and diffusional effects, and (d) a particle size distribution which varies with time. Semi-theoretical, rather than purely empirical, treatment of such processes in their developmental stages will result in a better understanding of the physico-chemical mechanisms in effect. This, in turn, will allow reliable process designs to be made on reasonable time scales for reasonable development costs. Once a production unit is built, such an approach will provide straightforward methods for process control and optimization. A research and development effort to determine criteria and procedures for semi- theoretically characterizing such mineral leach recovery processes has been initiated in a joint venture by the Arizona Bureau of Mines and the College of Mines at the University of Arizona. This group has as its task the mathematical characterization of hydrometallurgical leach recovery processes using semi- theoretical mechanisms for the underlying phenomena. The resulting models are experimentally verified and parameterized on the laboratory scale in such a way that they can be utilized with similarity criteria to provide reliable scaleup to production designs. This discussion will be centered around the elements of such an approach and how they fit together.

Jan 1, 1975

By Richard Campbell, MEHMET KIZIL, Ismet Canbulat, Serkan Saydam

The design and effectiveness of ground consolidation to regain stability of longwall faces vary widely and are often based predominantly on-site precedence or what were considered successful applications at other sites in similar situations. Little is known regarding product migration characteristics or change in rockmass conditions as a result of the application of consolidation chemicals. This paper presents the in-situ testing rationale designed and implemented recently across several longwall operations in the Bowen Basin, Queensland, Australia to provide quantitative measurement of the actual zone of influence of various resin injection products. Product migra- tion was physically measured by monitoring the change in rockmass temperature as a result of the exothermic chemical reaction of the various strata consolidation chemicals used. In conjunction with strata coring and Lugeon transmissivity testing pre- and post-injection to characterise the improvement in rockmass conditions due to consolidation product injection. The results of the testing programme, migration measurements, and rockmass assessment are presented, along with a discussion on how site- based Rock Mechanics Engineers can incorporate the data into the design of strata consolidation plans.

Jun 25, 2024

By J. E. Murphy, L. A. Walters, F. H. Nehl, G. B. Atkinson

The US Bureau of Mines investigated the selective electrowinning of Ag and Au from cyanide solutions contaminated with Cu with the goal of decreasing the amount of Cu codeposited. Decreasing Cu codeposited will reduce refinery costs. Direct current was applied to the cell in pulsed and square wave voltages at 0.7 A h/150 mL of solution. Times tested for each cycle ranged from 1 to 10,000 msecs. Graphite, lead and stainless steel were evaluated as electrode materials. Square wave electrowinning at 70°C (158° F) gave the best separation of Ag and Au from Cu. Applying 2.5 V during the duty cycle, 0.0 V the rest of the period, a duty cycle of 10% to 30%, and a period of 100 msecs to 1000 msecs gave the following results: Ag concentrations decreased from 34 µg/mL to 0.1 µg/mL. Au concentrations decreased from 54 µg/mL to 0.2 µg/mL and Cu concentrations remained almost constant at 560 µg/mL.

Jan 1, 1995

By R. A. Cummings

From before the turn of the century until as recently as the 1950s, relatively shallow coal reserves near the margins of the Illinois Basin were extracted by room- and pillar methods. Subsequent development has, in many cases, extended onto ground with high subsidence potential. The same state of affairs exists in many other historical coal mining districts, as well as in Illinois. Pit subsidence in Illinois is particularly common in the towns of Streator, Carterville, and Herrin, although there are others. Pit subsidence is characterized by distinct circular or oval depressions and normally is associated with shallow mining and thick soil relative to the thickness of rock.

Jan 1, 1985

By B. Derin

In this study, the Reddy-Blander model was applied to predict the sulfide capacity (CS) values of FeOx-CaO-SiO2, FeOx-MnOx-SiO2 and FeO-MgO-SiO2 ternary slags, which were experimentally studied in the literature within the temperatures between 1,673 and 1,923 K. As expected, sulfide capacity values of the slags increased with increasing temperature and decreased with increasing acidic content. The model was found to be in agree-ment for all slag systems at the temperature range of 1,773-1,923 K. However, a disagreement occurred when the basic content was relatively high, at 1,673 K for FeOx-CaO-SiO2 and FeO-MnOx-SiO2 slags. The effect on the CS of high amounts of Fe+3 and Mn+3 in the slags is discussed.

Jan 1, 2011

By R. K. Agarwal

In this paper a simple three-layered medium is considered. A circular hole is centrally located in the intermediate layer. The layered sheet is loaded uniaxially perpendicular to the stratification. The Young's modulus of the intermediate layer is lower than that of the outer layers. The stress distribution around the circular hole in a stratified medium is significantly different when compared to the case of a continuous homogeneous medium. The distribution depends upon the ratio of the height of [the] intermediate layer and [the] hole diameter. A comparison of stress the distribution and procedures for preparation and testing of [the] model are given. The potential of the technique is outlined.

Jan 1, 1968

By Jerry R. Riding

Metallurgical process methods have seen dramatic improvement over the past fifty years. As these improvements have come about, more and more emphasis has been placed on obtaining accurate and rapid analysis of the metallurgical processes. Well-defined conventional laboratory analysis procedures which have proven to be reliable were developed early in the mineral industry's history; however, these conventional procedures, which have not changed appreciably in fifty years, have the serious drawback that they are too slow to be of appreciable value in automatic control of the processes. For example, the assay results normally become available to a mill operator from eight to twenty-four hours after a sample is taken. Since the desired mineral separation can only be made while the minerals are in the flotation circuit, conventional assay results provide information similar to postmortem reports. Consequently, using conventional procedures, the mill is operated with information from an earlier period of time, which may not reflect current conditions. In recent years there has been a steady increase in the volume of required samples. At the same time, labor, material, and overhead costs have continued to rise causing the cost per assay to reach an alarming level. This rising cost per assay, plus the increasing demand for rapid analysis necessary for control, has caused the mining and metal processing industries to look toward other techniques to solve these problems As a result, X-ray fluorescence which can provide on-stream analysis necessary for control, as well as perform numerous laboratory assays at lower cost and at a much greater speed than conventional methods, has gained wide-spread attention. In addition, multichannel X-ray fluorescent instruments are now available which have been perfected to the point where the analysis of the most important chemical constituents is available within one minute after a sample is presented to the X-ray analyzer. Because of these obvious advantages, extensive use is being made today of X-ray analysis in the mining industry to analyze slags, ores, and mineral content of rocks. The results are used to make quick decisions for both mining and beneficiation of metals. For example, X-ray systems which provide rapid on-stream analysis of the slurries at desired points Fn metallurgical processes have recently been developed. The successful application of these systems has moved the milling process a step closer to fully automatic control.

Jan 1, 1969

By W. R. Dearman, N. Turk

A seismic fissuration index (K) is defined as the ratio of the difference in the P and S wave velocities obtained when a dry rock specimen is tested both under a load equal to half the uniaxial compressive strength of the rock (Vo) and without an applied load (Vd) to the velocity obtained without an applied load (Vd), as K = (Vo - Vd)/Vd. A similar seismic fissuration index is also proposed for classifying the dry rock mass in terms of field seismic velocities. The field equation is extended by including the intact rock seismic velocities. K is found to be related to the porosity of rocks. The proposed equation can equally be used for characterizing saturated rocks, using S-wave velocities. However, the time average equation should be used for characterizing saturated rocks, using P-wave velocities, even though this equation gives upperbound estimates of the rock material and fracture porosities.

Jan 1, 1986

By Richard J. Fantel

This paper addresses the impact of declining world rutile resources upon the production of titanium products and their asso¬ciated costs. Titanium is used primarily for the production of pigments; in its metal form it is considered a strategic and critical material to the U.S. defense and aerospace industries. There are two major mineral sources for titanium: ilmenite and rutile. Both these mineral types can be used to produce titanium pigments. Only high grade titanium concentrates, such as rutile, high-grade ilmenite, and synthetic rutile (which is produced through further processing of ilmenite), can be used in the production of titanium metal. This paper draws upon the data and analyses of a recent Bureau of Mines Minerals Availability Program appraisal that evaluated the international availability of titanium from market economy countries. The paper will show that production from economic rutile mines will decline sometime after the turn of the century and that rutile shortages could be alleviated by production from other high-grade titanium resources such as higher cost rutile deposits and anatase deposits, or through an increase in world synthetic rutile capacity.

Jan 1, 1984

By J. L. Fuller

Thousands of mine air samples are taken underground each year by MSHA inspection personnel in order to further assure that miners have a safe and healthy environment in which to work. While most air samples are taken with stain tubes, many samples are obtained in evacuated containers and returned to a laboratory for more accurate analysis on a gas chromatograph. In order to enhance the accuracy, reliability and repeatability of the samples taken with evacuated containers, improved procedures have been developed, which are described in this report, for filling two different types of evacuated sample containers using either mechanical or electrical pumps. In those instances, such as when sampling strata gases in drill holes, where mathematical calculations may be required for proper sampling, example calculations are provided. The use of a third type of evacuated container, which is generally restricted to non-specific sampling of the ambient mine atmosphere, is also described.

Jan 1, 1986

By Frederick P. Agterberg

It can be useful to model the mean grade values for a metal in mineral deposits containing that metal as representing the extreme value tail of a lognormal frequency distribution for the concentration values of the metal in rocks of all types. Results for copper and zinc in the Abitibi area of the Canadian Shield are compared to results previously obtained for the Canadian Appalachian Region. The lognormal model is also applied to a set of 162 large gold deposits in the Abitibi area. In the second part of the paper, 1311 large and small gold deposits in the Abitibi area are modelled as discrete events. By means of a newly developed spatial clustering model it is possible to predict the variances of random variables for frequencies of deposits in cells of different sizes.

Jan 1, 1979

The Bureau of Mines, U.S. Department of Interior, is currently investigating strata interactions associated with the mining of multiple coalbeds. Strata interactions due to subsidence are a result of undermining. This study involves underground investigations at a mine where room and pillar panels are actively being developed through an area of the Sewickley Coalbed which was subsided by undermining of the Pittsburgh Coalbed. Research to date indicates that undermining had little effect on upper mine pillar stability, but had a more severe effect on the development and maintenance of entries. Roof-to-floor measurements recorded over four times more convergence in entries developed over gob as compared with entries developed over support pillars in the lower mine. Consequently, this has led to major roof falls in the active panels, resulting in considerable production delays and supplemental roof support costs.

Jan 1, 1985

By J. K. Wilmshurst

Absorption, emission and reflection techniques for the study of [molten] inorganic materials at high temperatures have been critically examined. In general, the reflection technique is the most satisfactory for tine study of pure materials, while the absorption, and possibly also the emission techniques, may be useful for studies of certain dilute solutions. In the present investigation infrared emission spectra for sodium nitrate and silver chloride were obtained together with absorption spectra derived from reflectivity data by the method of Robinson and Price for sodium nitrate, silver chloride, lithium and potassium fluoride and their 1:2, 1:1 and 2:1 mixtures and for solutions of zirconium tetrafluoride in lithium-potassium fluoride (1:1) and sodium-potassium fluoride (1:1). It is concluded that vibrational spectroscopy cannot give unambiguous information concerning the existence of complex ions in fused salt, mixtures.

Jan 1, 1963

By R. Bruce Sheibach

The Picher Mining District, located principally in north-eastern Oklahoma, was one of the world's largest lead-zinc mining areas during its 55 year life. The field covers an area of approximately 72 square miles (186 km.-); an estimated 1.6 x [103 yds3 of material (1.22 x 103m3)] worth in excess of one billion dollars, has been mined. Mining activities were typified by surface exploratory drilling identifying ore distribution and extension of underground workings to the lead and zinc deposits outlined. Exploration holes were either left unplugged or plugged at the surface with a section of a telephone pole. Low grade ore and waste rock were discarded in mined out portions of drifts. These waste piles containing pyrite and marquisette were left underground and oxidized during the many years of active mining. Upon cessation of mining activities in the mid-1960's, the drifts and shafts of the abandoned workings began to flood as the cone of depression filled in, leading to the dissolution of the oxidized sulfides and the formation of large volumes of acid mine water in the mined out openings. The resulting poor quality water, with high concentrations of cadmium, iron, lead and zinc, began discharging at the surface in 1979. Contamination of the underlying aquifer supplying local residents was first detected on a localized scale in 1980. The present surface water and ground water contamination have lead to the area being classified as one of the top ten hazardous waste sites in the U.S. by the EPA under the superfund program.

Jan 1, 1982