Search Documents

By Kenneth S. Johnson

Oklahoma is a region of complex geology where a mobile belt of Paleozoic geosynclines and uplifts on the south abuts against the margin of the North American craton to the north. The state contains many classic areas where fundamental concepts of sedimentation, stratigraphy, structural geology, historical geology, mineral investigation, and petroleum exploration have been formulated through the years. In the southern Oklahoma mountain belts, there are exposed a great variety of igneous and sedimentary rock units seen at few other places in the Midcontinent area. Major geologic provinces of Oklahoma (Fig. 1) include: (1) the cratonic and relatively stable northern shelf areas, including the Ozark uplift; (2) the Ouachita geosyncline (now the Ouachita Mountain belt) and associated Arkoma basin in the southeast; and (3) the southern Oklahoma aulacogen (geosyncline), comprising the area of Anadarko, Ardmore, Marietta, and Hollis basins, as well as the Arbuckle and Wichita Mountain uplifts. The three principal fold belts, the Ouachitas, Arbuckles, and Wichitas, all originated from a series of Pennsylvanian orogenies (about 300 million years ago) in the two Paleozoic geosynclines.

Jan 1, 1999

By Andrzej Wala, Tom Altman, Tom Hughes

The University of Kentucky Mine Ventilation Manager (UKMVM) is a system that contains Level Five knowledge bases and comprises an expert mine ventilation management system. The package uses production rule language (PRL) to interpret data monitored from sensors, e.g., for airflow, temperature, and concentration of gases, in an underground mining environment. Activated from the PRL knowledge bases are Pascal subprograms which (1) organize the monitored data to set up emergency consultations, (2) display graphic representations of a mine's ventilation network with the latest sensor readings, (3) provide interactive updating of mine ventilation parameters, e.g., resistance changes, revised flow requirements, and new regulator and fan settings. Also activated from these knowledge bases are programs which (1) monitor airflow, temperature and gas concentrations from a physical mine ventilation model and (2) adjust regulator openings and fan rpm's. Thus, as an expert system the UKMVM not only presents advisory consultations for underground environmental emergencies, but also serves as an interface between the monitoring and responsive control aspects in the continuous maintenance of normal mine ventilation.

Jan 1, 1989

By Robert J. Auber, Thomas R. Scotese

The West Leg Interceptor is part of a new sanitary sewer system in the southwest suburbs of Cleveland. The first two construction contracts were excavated in glacial soils varying from hard tills to pressurized silts and flowing sands. These soil and groundwater conditions were locally problematic during shaft and tunnel excavations and final lining construction. A variety of solutions were developed primarily during construction. During the WLI-1R Contract, subgrade pressures, continued ground losses, and displacements necessitated extra eductor wells and modified inverts for stabilization of shafts. At the WLI-2Contract, one shaft excavation in similar ground required only one extra well. In the WLI-1R tunnel, localized inflows of groundwater, silt, and sand through the geotextile fabric were stopped by cement grouting. In one WLI-2 connector tunnel, damage to the TBM flood doors combined with wet, flowing silt and sand led to ground losses, surface settlements, plugging, patching, and chemical grouting. The concrete lining in the main WLI-2 tunnel required remedial work to improve watertightness at joints.

Jan 1, 1999

By W. S. Urbanski, A. L. Devernoe, M. S. Walker

Theory and practice are described for a new processing method capable of precise mineral separations based primarily on differences in particle specific gravities at specific gravity split points from 1.5 to 21.0 and beyond. Separations are analogous to those achieved using rotating heavy media, except that the effective specific gravity of the fluid is created magnetically using a relatively dilute, low-viscosity, water-based magnetic fluid. Results reported here for a large, laboratory flow-through separator include: 1) 99% grade with 97% recovery in single pass separation of a suite of heavy minerals from quartz at I0 kg/h, 14 tph/rm2 of duct cross section, 2) 90% grade and recovery in single-pass separation of mixtures of sand-size, non-magnetic rutile (4.23 specific gravity) and zircon (4.72 specific gravity) at throughputs of 35 kg/h, 47 tph/rm2 of duct cross section, 3) partition curves having Ep90-10 transition widths 5% or less of mineral specific gravities, and 4) essential confirmation of the theory.

Jan 1, 1991

By W. A. Hustrulid

Introduction A problem that has faced mining engineers and mining geologists for many years is how to best explore a particular prospect so that the basic decision as to whether the material present is ore or only high-grade rock can be made with some confidence. It is obvious that one could not begin a large scale mining program on the basis of tests made on a few hand samples. On the other hand, one could not be 100 percent certain as to the average grade or tonnage before beginning development, as this would require the orebody to be mined out in the sampling process. The basic objectives of the exploration program can be stated as (1) to reduce mining risk; (2) to lessen the cost of development; and (3) to increase the profits of mining. The exploration program should be terminated when these objectives are no longer being met. The construction of tunnels is a specific mining operation. In the exploration program one should gather the data needed to determine (1) the type of excavation technique(s) to be used; and (2) the rate of advance that might be expected. As in the evaluation of an orebody, with the data collected it should be possible to estimate mining costs and project life. Unfortunately, at the present time, it is not possible to do this at least when dealing with medium to hard rock types. The reason for this, it is felt, is basically the inability to identify what specific rock mass properties are of use in tunnel design and to specify how these may be obtained in an exploration program. In short, the exploration program should be designed to give information regarding both the volume (length) and 'grade' (in

Jan 1, 1997

By John D. Smart, John W. Sager

The following paper is an evaluation of the instrumentation programs on recent Corps of Engineers tunneling projects. The authors have first-hand knowledge of the NORAD Cheyenne Mountain Complex (NCMC) Expansion Project. Information on the other projects comes from conversations with those directly involved in the instrumentation programs and from referenced reports. The specific objectives of this paper are: (1) to state the purposes of the instrumentation programs, (2) to discuss the benefits gained from the instrumentation, and (3) to present conclusions from this study that will provide guidance to those planning instrumentation on future projects. Presentation of detailed descriptions of the projects and instrumentation data is limited to that necessary to the accomplishment of the above objectives. NCMC EXPANSION PROJECT The NCMC is located at a depth of approximately 800 feet in Cheyenne Mountain near Colorado Springs, Colorado. For the current expansion project new chambers were mined to accommodate a new diesel power plant and associated cooling and air handling equipment. During 1971 some 55,000 yd3 of granite were mined through existing access tunnels for this expansion. A model of the new excavation is shown in Figure 1. The light shaded areas are new openings, and the dark areas are portions of the existing operating complex. The large chamber to the right is the power plant chamber and has a span of 67 ft, a height of 50 ft, and a length of 172 ft. The other large chamber on the lower level is the cooling tower chamber and has a span of 38 ft, a height of 45 ft and a length of 185 ft. The small chamber on the upper level has a span of 20 ft and is 27 ft high and 140 ft long. Other major excavations are the 18 ft diam air tunnel

Jan 1, 1997

By J. C. Norman

The boron review did not arrive in time for publication in the June issue. The United States was the world's largest producer and consumer of boron compounds during 1992. The US Bureau of Mines estimated that boron mineral concentrate and chemical production in the United States totaled 1Mt (1.1 million st) in 1992, yielding 521 kt (574,000 st) of B203 for a total estimated value of $333 million. That was about 20% less than 1991 revised production figures, and less in value by $107 million. The United States continues to provide essentially all of its own boron supply while maintaining a strong position as a source of sodium borate products and boric acid to foreign markets. Domestic employment in the mining and beneficiation of boron products in 1992 was about 900 people, the same as in 1991. In 1988, 1250 people worked in the boron industry. The Bureau estimated that total world production of boron in 1992 was about 3 Mt (3.3 million st), or about 1.2 Mt (1.3 million st)of B2O3. World production in 1992 was about equal to revised 1991 levels. US production Mines and processing operations in southern California were the only domestic sources of boron mineral concentrates and chemicals. US producers, in order of quantity of production, included:

Jan 1, 1993

By J. David Lowell

This paper describes the geology of the Kalamazoo copper orebody discovered in the course of an exploration project carried out by Quintana Minerals Corporation under the author's direction in an area immediately southwest of the San Manuel mine, Pinal County, Arizona. In the period 1943-1947, exploration projects were carried out in the San Manuel area by the U.S. Bureau of Mines and Magma Copper Company which resulted in the development of the San Manuel underground block-cave mine which is now in production at a rate of 41, 000 tons per day. Mining claims covering the area immediately west of the San Manuel orebody were staked in 1946 by Frank F. Salas, R. A. Buzan, H. G. Buzan, and W. C. Buzan of Mammoth, Arizona. These claims were optioned to Martha Purcell in 1946, and in the period of 1947-1958 seven churn drill holes ranging in depth from 1,400 to 2,950 feet were drilled by Mrs. Purcell. These holes did not intersect ore and no further deep exploration was attempted prior to the Quintana Minerals project which began in August, 1965, and which is described in this report. The Kalamazoo deposit is in Sections 3, 4, 9, and 10, T 9 S, R 16 E, Pinal County, Arizona, and it is reached by driving seven miles east from Oracle, Arizona (Figure 1) . The writer is indebted to Corbin J. Robertson and Ronald B. Thompson who participated in the exploration planning of this project and to a number of other individuals who contributed to its execution and management. Petrographic work by J. M. Guilbert was used as a basis for rock and alteration classifications.

Jan 1, 1968

By C. O. Brawner

Geotechnical theory is reasonably well developed to evaluate the stability of rock slopes for surface mining projects. It is recognized widely that structural geology, groundwater pressures and seepage, and blasting are key factors that influence the stability of such slopes. However, our capabilities to model the structural geology, to determine rock strength along discontinuities and to model groundwater pressures and profiles are still very approximate. Plus, practical experience of the rock mechanics engineer is one of the most important inputs to the design of open pit mine slopes. To emphasize the use of practical experience, a number of case examples are reviewed here to illustrate key factors that must be evaluated. These case examples comprise a continuation of other examples presented in the Jackling lecture to the SME in 1986 by the author (Brawner, 1986). Example no. 1 In situations where the orientation of geologic discontinuities will not influence rock slope stability, extremely steep slopes can be developed, providing blasting and groundwater are controlled adequately. An excellent example of this condition is the Republic Pit of Cleveland Cliffs in Michigan. The rock slope in Fig. 1 isover400fthigh with a face angle of approximately 80". The rock is hard and massive, and blasting was carefully controlled. The original design of this slope was at45", a standard design angle at that time. The competency of the rock and the lack of critical geologic structure subsequently was recognized, and the much steeper slope angle was developed successfully. The rock proved to be so competent and the slope sufficiently stable that an underground crusher station was developed with entrance and exit tunnels excavated at the toe of the steep wall.

Jan 1, 1991

By N. S. Tanious

Three water-spray ventilation systems were tested to determine their effectiveness in diluting methane at a room and pillar coal mine face. These systems were: the shrouded nozzle, the spray fan, and the conventional nozzle system that is normally supplied with continuous miners. The testing was carried out in two stages. The air-moving capacities of the nozzles were first evaluated in a duct. The duct tests showed that: (1) the volume of air moved by the nozzle is controlled by the type of nozzle, the space around it, and its location relative to the duct wall; (2) the spray fan nozzles or the shrouded nozzles are both capable of moving air quantities up to 6400 cfm (3.02 m3/s); and (3) when the shroud was removed from around the shrouded nozzle, its bare nozzle moved between 9 and 65 percent more air. In the second stage of testing, a full-scale evaluation of the three systems was conducted. The three spray systems were mounted on a continuous miner which was positioned in an aboveground simulated mine entry. The simulated face tests gave the following results: (1) the standard nozzle system, which is mounted on the front end of the miner, is inadequate for diluting methane; (2) under the best testing conditions (lowest methane emission rate, highest primary ventilation airflow, and closest brattice set back), the slight improvement given by either the shrouded system or the spray fan is the same; and (3) under the worst testing conditions (highest methane emission rate, least primary ventilation airflow, and farthest brattice set back), the spray fan gave superior performance.

Jan 1, 1987

By Matias Pentinnen, Wayne Dickinson

Electrowinning is a key process for copper production contributing roughly twenty percent globally and thirty to forty percent of production in the Americas1. Copper grade is assessed largely on deposit smoothness and on level of impurities in the metal. Smoothing aids are essential to create dense, low porosity deposits and guar has long been the material of choice for this purpose. Guar is, however, poorly stable under the strongly acidic electrowinning conditions, underlying ongoing research to identify an effective, acid-tolerant replacement. Current efficiency is also a critical factor in controlling copper production costs and chemical additives should ideally improve current efficiency as well as improving deposit smoothness.

Feb 1, 2025

By Edmund W. Murphy

At the first workshop on Surface Subsidence Due to Underground Mining (1 981 ) , Yarbrough delivered a paper (1 ) describing the mine subsidence insurance program in Illinois operated as the Illinois Mine Subsidence Insurance Fund (IMSIF) . In this paper we will present claims data and describe changes that have occurred in the Illinois Insurance Code during the first six years the IMSIF has been in existence. The change in the original Illinois Public Act 80-1 41 3 that most affected the public was an amendment increasing the maximum amount of mine subsidence insurance avail- able on a structure from $50,000 to $100,000. Seventy-two counties in Illinois have been undermined for minerals, primarily bituminous coal. In Franklin County (.in the southern part of the state) 36 percent of the land area has been undermined for coal extraction. In St. Clair and Madison Counties , two counties that include the St. Louis Metropolitan area along the western border of the state, 10 percent and 7 percent of the land surface have been undermined. Most of the undermined area in the two counties is beneath urbanized land. In 34 counties, approximately 1 percent or more of the land surface has been undermined (2). The first shaft mine in Illinois was sunk in the city of Belleville (east of St. Louis) in 1842, and the mines of early vintage have initiated the majority of the mine subsidence claims. Data compiled from the first six years reveals that most Illinois mine subsidence events that affect structures occur over abandoned mines where early methods of high- extraction mining practices were used. Maps of these mines operated in the 1800s reveal irregular development of room and pillar areas and poorly defined production areas (panels). Rooms in the mines varied from 15 to 40 feet in width and the pillars varied in width from 5 to 40 feet. The pillars were often long and narrow. Recovery rates in mines that operated prior to 1900 generally averaged 50 per- cent, and extraction rates as high as 80 percent have been documented (2). Some pillar robbing occurred.

Jan 1, 1986

By J. C. Agarwal

Major scientific discoveries cannot be programmed. New or frontier technology, however, can and should be planned. It is the vital force underlying the business strategy of a vigorous and profitable mining and metals company. Generally, a radical departure from existing technology is required to 1) Enhance the competitive value of ore reserves, i.e., to turn low grade or marginal reserves into competitive reserves. 2) To increase yield and decrease costs. 3) To decrease investment. 4) To increase mine life. 5) To improve product quality to meet market demands. The very definition of frontier technology implies that it is so different that the old plant, if already in use, will not be directly suitable to use the new technology. Therefore, a priori, we know that the commercialization of frontier technology would very likely involve new investment. The recommended technique of economic and technical analyses, I propose to call "Success Analysis.'' Simply stated, it forces us, by step- by-step procedure, to ask "what is needed to succeed in this particular project." Therefore, the first step is to identify what is meant by "success." The definition of "success" requires an agreement with top management or sponsors of the project as to what constitutes "success" in their minds as contrast to the technical people perception of "success." In general, top management would define success as meeting: 1) The technical objectives, i.e., technology being developed would produce the desired product at the acceptable quality. 2) Financial objectives, i.e., when commercialized, the project's capital cost, operating costs and return on investment are better than the projects they would normally fund. The return has to be better because new technology is inherently riskier. 3) Marketing objectives in that the project will produce product of acceptable quality in timely manner, i.e., scale-up to commercial plant would not cause undue delays in start-up and that large fix-up expenditure would not be required to protect the projected return on the investment. Many projects are started in the laboratory to develop "Frontier Technology" in mineral processing. Most of these efforts are never commercialized. There are many causes of these failures. The major causes are listed below: 1) Inadequate communication with the sponsors of the project so that project objectives are defined and agreed to by all. 2) Ill-defined technical problems. 3) Incomplete development of technology. This has two major components: a. Incorrect scale-up and engineering. b. Inadequate start-up and maintenance planning. 4) Incomplete and over-optimistic process economics. 5) Lack of understanding of the future behavior of the marketplace. 6) Failure to complete R&D effort by the time it is needed. 7) Incorrect projections of human resources required; that is, technical, managerial and operating. 8) Lack of realistic forecast of the expenditures required for commercialization of the R&D effort. These pitfalls can be avoided by comprehensive planning and the use of success analysis technique. The major elements in "Success Analysis" are: 1) Identification of the "need" for new technology. 2) Unbiased and complete scale-up engineering. 3) Acceptable economic feasibility with enough margin of error in the sale prices and operating costs to justify the inherent risks in frontier technology. 4) Timing for availability of investment capital and markets. Many failures in the development of frontier technology are preordained because the initial selection of the research project has been without adequate attention to the needs of the industry. Many very innovative hydrometallurgical processes for recovery of copper from concentrates were developed in the past twenty years. They have not adapted except to a very minor extent because they did not satisfy the success analysis criteria. The copper industry in North America needed a process to compete against high grade ores and to avoid

Jan 1, 1985

By Yu. A. Polozov, V. A. Lagunov, O. Yu. Lushinkova, Yu. I. Svirskiy, Eh. Ya. Kipko, Roy A. Williams

The reliable quality assessment of grouting operations is one of the key issues in establishing impermeable grout curtains around shafts, drifts and tunnels. Reliable opera¬tional information on the decrease in the permeability of rock during the grouting process facilitates the assessment of the effectiveness of the completed curtain and assures production quality. Quality control and assurance also fa¬cilitates the early detection and elimination of possible de¬fects in the grout curtain. Thorough control of the grouting process provides the capability to evaluate decreases in the permeability of water-producing fracture zones prior to the beginning or the continuation of excavation of the shaft, tunnel or drift. In order to achieve this objective, post¬grouting hydrodynamic investigations are conducted prior to the initiation or re-initiation of work on the underground workings to measure the decrease in the permeability coef¬ficient of aquifers during grouting operations. 8.1 QUALITY ASSURANCE AND CONTROL OF THE ISOLATION OF ROCK BY GROUTING THROUGH HOLES DRILLED FROM THE SURFACE Quality assurance and control are based on measuring the decrease in the permeability coefficient of water-pro¬ducing horizons as a result of injecting grout into the drill¬holes. For this purpose, the value of the acceptable residual permeability coefficient is calculated beforehand based on the acceptable value of ground water inflow into the shaft, drift or tunnel as specified by the "construction norm and integrated practice (SNIP)" (Anon., 1976). Having ob¬tained the values of aquifer thickness, permeability, and head distribution for each aquifer from flowmetric data (dis¬cussed in Chapter 3), the average value of the permeability coefficient of all aquifers intersected by the shaft is calcu¬lated as [ ] where Ki is the permeability coefficient of the "ith" aqui¬fer; Pi is the pressure of the "ith" aquifer; and M; is the thickness of the "ith" aquifer. The total expected inflow of ground water into the shaft is [ ] where RK is the radius of the contour of influence; RCFB is the radius of the shaft; and p is the coefficient of dynamic viscosity of the ground water. The necessary reduction of the coefficient of permeabil¬ity of the aquifer [ ] where Q is the expected inflow of ground water into the shaft from eq. 8.2; Q.-fin is the acceptable inflow of ground water; and a is the safety factor. By knowing the average permeability value of the rock and the permeability reduction coefficient, it is possible to determine the value of the acceptable residual permeability coefficient for all the aquifers [ ] The values of the permeability coefficient, pressure, and thickness for each aquifer are determined from the data gathered during the hydrodynamic investigations conducted in grout holes prior to beginning the grouting operations as discussed in Chapter 3. After injecting the grout into the first of the holes, the injection into each of the following grout holes is preceded by repeated hydrodynamic investi¬gations. Using the data obtained for each water-producing zone, a graph is constructed where the numbers representing the grout holes in their order of grouting are placed on the abscissa, and the values of the aquifer permeability coeffi¬cient are placed on the ordinate (Fig. 103). This curve char¬acterizes the change in permeability of the given hydro¬stratigraphic unit as grouting operations are completed, one hole at a time. The results of grouting operations are considered to be positive when each sequential observation records a steady decrease in the permeability of the aquifer. The permeabil¬ity measured prior to the injection of the grout into the last hole must be lower than or equal to the acceptable perme¬ability as determined by the application of eqs. 8.1 through 8.4. Table 8.1 presents illustrative data on the hydrogeo¬logic properties of aquifers at a mine shaft prior to the initiation of grouting operations. Data also are presented on the reduction in the permeability coefficient during the in¬jection of the grout. The shaft in question intersects eleven aquifers. Based on data concerning aquifer pressure, thick¬ness, permeability, and the expected inflow rate of water for each of the strata, the average permeability coefficient is calculated according to eq. 8.1 as K = 0.2 x 10-12 m2. The

Jan 1, 1993

By R. W. Utley

Over one half billion tons of coal per year is scalped, classified, deslimed, drained and rinsed, dewatered and final sized on rotary, vibrating, shaking or stationary screens. The vibrating screen is the industry work horse and performs the bulk of the screening functions in the coal preparation plant. There are two major types of brute force mechanical vibrating screens used in coal preparation plants: (1) the two-bearing one-shaft inclined screen and (2) the four-bearing two-shaft horizontal screen. Both of these types are familiar to coal producers.

Jan 1, 1966

By H. Evans

It is well known that iron-ore pellets are considered one of the best blast-furnace burden materials used today. The demand for pellets is demonstrated by the increase in pellet output from one million tons in 1955 to approximately 37 million tons in 1964. This growth continues as new plants are placed on-stream each year. The consumer generally specified (1) the acceptable content and range of chemical constituents, (2) a minimum strength determined by some standard testing procedure, (3) the size range of pellets, and (4) perhaps a measure of reducibility.

Jan 1, 1966

By Gerald J. J. Aleva

Lateritization is a surface and near-surface process enhanced by a humid and warm climate and by good drainage. It closely follows the development of the regional landscape. The cyclic landscape development on the Guiana Shield is accompanied by a progressively thicker and more evolved laterite mantle the older, and hence in most instances the higher the planation level. The known, economically interesting bauxite and aluminous laterite eposits of the Shield are restricted to the remnants of the oldest of the Cainozoic planation levels (level I1 and 111).

Jan 1, 1984

By Robert Dunne, Paul Gelfi, Vernon Martins

The New Celebration Gold Mine is located 32 km south of the regional mining centre of Kalgoorlie. The current mill throughput is 1.7 million tonnes per annum with a gold production of around 120,000 ounces per year. The main source of ore for the mill comes from the Hampton Boulder and Pernatty pits. Over the last two years the oxide reserves from these pits have been depleted and the harder primary sulphide ores are now being processed. This change has led to a decrease in cyanide extractable gold.

Jan 1, 1991

By Peter Krag, Rob Henson

It is well known that titanium and zirconium alloys offer superior corrosion resistance in the oxidizing sulfuric acid environments present in sulfide pressure leaching operations. The use of these materials is limited, however, due to their pyrophoricity; several accidents attributed to titanium equipment have been described in technical literature, and other, minor incidents·occur regularly1 • We describe an application of a commercial titanium alloy, Nb-55 Ti, with suitable mechanical properties, corrosion resistance similar to Grade 2 Ti, and featuring a significantly reduced field of ignition conditions

Jan 1, 1992

By Peter A. Dawson, Rod L. Leonard, Karen S. Christensen

An investigation has been completed of the technical and economic feasibility of construction of a processing facility for gold extraction from arsenical tailings, grading nearly 12 g/t, stockpiled near Snow Lake, Manitoba, Canada. The tailings dump is comprised of arsenopyrite (45%), pyrrhotite (12%), and gangue constituents. The majority of the gold occurs as fully encapsulated particles or as a solid solution in the arsenopyrite grains. The chemical composition of the Snow Lake tailings (referred to as "ore" throughout the remainder of the text) is shown in Table 1.

Jan 1, 1990