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By William C. Grady

The environmental and economic problem created by pyrite in coal are well documented. The removal of pyritic sulfur prior to, or during, utilization has been the object of considerable research, however, much of this research has proceeded without a proper knowledge of the microscopic occurrences of pyrite in coal. This paper investigates the forms, occurrences, and variations in the distribution of pyrite in major West Virginia coal scan. Twenty-nine samples from twenty-two major west Virginia coal scans were selected for this study (see Table I). The samples were selected so as to be representative of the major coal producing areas of the state. All samples, except five, were collected at active surface mines, as indicated in Table I, and all except one were channel samples. The time interval between sampling and preparation of polished microblocks varied from two months to two years, though most were prepared within three months of collection. Grinding, screen¬ing, and riffling of samples to obtain 250 grams of -20 mesh coal for microscopic analysis strictly followed ASTM procedure D2013-72.

Jan 1, 1976

By Ben L. Seegmiller

The artificial stabilization of a pit slope at the Twin Buttes Mine near Tucson, Arizona has been completed as part of a practical rock mechanics program. The research program began in June 1971 as a result of the three million ton South Slope slide(1) which caused significant economic and operational problems. Hydrological studies, field and laboratory testing and investigation of various stabilization systems(2)occupied the first year of research. In July 1972 a design for an artificial stabilization test using post-tensioned cable bolts was completed and the selection of an outside contractor was made the following month. The project began in mid-September and was completed during the first week of January 1973. The test site is located adjacent to the South Slope slide in a zone of high potential failure. When the site was initially selected it was thought that it would remain stable at least until the test could be completed. However, heavy rains which fell in late October induced displacement in the half of the test site adjacent to the South Slope slide. Prior to this stabilization test it was thought both impractical as well as improbable that a moving slide could be stabilized with an artificial support system(3). Because the project was nearing the half-way point it was decided that an attempt should be made to complete the test as originally planned. This meant, in effect, that an attempt would be made to stabilize the moving section as well as the stable section.

Jan 1, 1973

By Ron Derrick

SX operators have conducted extensive shut-downs and repairs over the years to mitigate solution leaks from failed stainless steel false floors and walls in rectangular mixersettler mix boxes. Hydrodynamic modeling using first principles and constitutive equations of fluid mechanics can inform an efficient structural redesign sufficient to eliminate the plate failures. Updated mix boxes have been performing without failure for over a decade. Given the extensive construction of the original Holmes and Narver mixer-settler design throughout the world that includes stainless steel lined rectangular primary and auxiliary mix boxes, SX operators may benefit from the approach, eliminating costly shutdowns, leaks to containment, and hazardous repairs.

Feb 1, 2024

By Thomas E. Garnar

Mineral sand products have been produced from beach sand heavy minerals for nearly a century. These minerals have specific gravities of 3.0 or higher and are extremely resistant to weathering. The most common economic heavy minerals are ilmenite, leucoxene, rutile, zircon, stauarolite, monazite, garnet, and the aluminum-silicate minerals. Of these, ilmenite is the most abundant. In some cases a deposit may contain only one or two economic heavy minerals whereas in others five or six may be present. Heavy mineral mining began in the late eighteen hundreds when monazite was mined for its thorium content. This was followed by mining activity on the North Florida coast just south of Jacksonville Beach - where ilmenite and zircon were first separated during the WW I (1,8). Modern heavy mineral mining began in Eastern Australia during the late nineteen-thirties and spread to the United States during World War II. It is the purpose of this paper to review the commercial heavy mineral products, their sources, and their uses.

Jan 1, 1985

By J. M. Marek

The determination of the proper cutoff grade for an open pit metal mine is based on economic criteria and the operating philosophy of the mining company. Previous papers have dealt with the balance of a fixed mine production capacity versus economic return. Mine production capacity is often controlled by the amount of mining equipment and the working area in the pit. A complete cutoff grade strategy is a balance of economic return of mining higher grade material versus the capital costs of additional production capacity and the operating cost of moving the waste and low grade material to assure proper ore release. An approach to the problem is presented which is based in part on work by previous authors and provides guidelines to proper cutoff grade strategy encompassing the time value of money and variable commodity prices.

Jan 1, 1985

By George Weinman

GEORGE WEINMAN: Our first group leader for the discussion, "Ups and Downs of Downsizing," wishes to remain anonymous. ANONYMOUS PRESENTER: When George and Jamie asked me to do this, I thought a while about what to say and went through several variations of what I’ll present today. I came up with the title "Ups and Downs of Downsizing." A lot of downsizing has occurred in all of our industries-mining in particular. While this downsizing has gone on there's no doubt that all of us produced more and more, probably with less and less people and less and less resources. But I contend that there's also a big downside associated with this. I disagree with a point made in the keynote presentation yesterday, the point being that vendors are bringing new technology to us. I can agree that the major changes associated with equipment and similar items are being brought to us by vendors. But I do contend that there's an awful lot that's getting away from us-especially if you factor in the integrated supply or the strategic alliance or the various and sundry related purchasing techniques. I contend that we are missing a lot of, let's call it, lesser technology; not major equipment changes, but different tools, different techniques for doing things, different left-handed widgets. The integrated suppliers, to some degree, are bringing this to us; but I am concerned about the small guy who comes up with a good idea but deals through integrated suppliers rather than having direct contact with plant people. They're probably going to go somewhere else and market their wares. That's what I'm hearing from a lot of smaller vendors. I also think that we are losing a lot of our knowledge base. Every time you shrink an organization somebody leaves. The bottom line: less people. When a person leaves-and I don't care who he or she is, be it the janitor who's cleaning the bathroom, the operator, the engineer-when that person leaves there's some knowledge that goes with that per- son. And sometimes that knowledge is quite valuable. I've worked more or less at the plant "low." I can't tell you how many excellent, viable projects have come from people who said, "Look here. There's a better way of doing this." And, you know, they were right. Now, maybe they didn't have the resources or the expertise to develop these ideas into full projects, but they had that basic idea. Someone may say, "Well, if we put a no. 6 skyhook here, so we can lift this particular pump without bringing a crane from 30 miles away ...." No. 6 skyhooks are a bit expensive, but what if we put together a little structural steel here or whatnot?

Jan 1, 1998

By A. D. Hoagland

There are large areas on all of the continents with environments which are favorable for deposits of zinc and lead of Mississippi Valley type. In the developed countries, these environments have for the most part been quite thoroughly explored for the near surface deposits, and it will be necessary to direct more effort to the search for deeper buried deposits from which much of our future production must come. The difficulties of exploration for deep ore of this type are many and formidable, but the area of permissive environments beneath deep cover is many times as great as the area of the known near surface ore districts. It is a reasonable assumption, therefore, that numerous deposits wait for discovery and development. The finding cost, however, is certain to increase, and it is essential that concepts and techniques of exploration be improved if we are to sustain a reasonably strong productive capability into the 21st century. Exploration for deeply buried deposits requires at the outset relatively large areas of favorable geologic environment. The favorable horizons must be within economic limits of depth for the exploration as well as for the mining techniques which are currently available; and there must be some condition, design or strategy which will assure the explorer a reasonable chance of obtaining maximum benefit from discoveries which he may make.

Jan 1, 1973

By W. W. Mason

The United States began exporting coal in the late 1800'5, at first in very small quantities to Canada and beginning in 1897 and 1896, to the east coast of South America. Shipments to European countries began on a very limited basis in 1902 and these shipments increased gradually until World War One when shipments overseas increased from the 8 million tons per year level to 22 million tons. After the war exports dropped as fast as they had increased and, with the exception of exports to Canada, remained at very low levels until just after World War 11 when the United States again emerged as a major coal exporter. World War II left the coal industries of Europe in ruin. As the United States was the only country able to supply the large quantities of coal at reasonable prices needed for reconstruction of the European economy, the U. S. coal exports overseas expanded rapidly to 42.5 million tons in 1947. Additionally, we shipped 25 -2 million tons of coal to Canada In that year for a total export of 68.7 million tons. Unfortunately, that level was not reached again until 1957 when exports reached an all-time high of 76 .4 million tons- -a high I might add that has not been reached since.

Jan 1, 1980

By Michael J. Pratko

The bulk handling industries have long been plagued with problems in their attempt to obtain one of their major goals - the maximum efficiency for which a bulk handling flow system was designed. Mentor Dynamics Ltd. is an international firm with offices in Canada, Japan, and the United States. Mentor Dynamics Ltd. is in the business of solving the "why not" of a system and engineers the solution for the problem. Studies of the varied difficulties encountered with bulk flow systems indicate that 90% of all flow problems fall into one or more of the following categories: abrasion, impact, sticking, and/or inadequate design. These problems can occur with a myriad of bulk solids: coal, gypsum, aragonite, phosphate, fly ash, ore. Solutions to the problems are as varied as the problems. The proper lining material, ceramic, urethane, rubber, and/ or ultra high molecular weight polyethylene, must be coupled with the correct fastening system, annular ring and 'F' cap, weld washer, button head fastener, weld studs and/or nuts and bolts.

Jan 1, 1982

By R. H. King, D. R. Schricker, R. E. Cameron

Mine managers rely on their experience, section foreman's daily reports and occasional time studies to make important production, maintenance and forecasting decisions. This information is often subjective and imprecise, consumes expensive engineers time, is often biased and is restricted to short time periods. Managers need better information. Furthermore, if a recently purchased machine is being evaluated, a large increase (>10%) in productivity may be obvious, but small increases are usually masked by other variables. In today's highly competitive markets, cumulative small changes are important, especially since managers have already exhausted most available, obvious avenues of improvement. A technique to separate these charges from effects of other variables and to quantify the target effect is necessary. CSM researchers are addressing this need by developing an intelligent decision support system (IDSS). It provides key production and maintenance information to support management decisions by recognizing patterns in mining machine sensor data and representing knowledge about mine management, operations, layout and equipment. A continuous miner section at Western Fuels-Utah Inc.'s Deserado Mine in Rangely, CO is the test facility for the research. Power transducers located in the sections load center provide kilowatt versus time data from continuous section equipment. The IDSS pattern recognition algorithms classify the kilowatt versus time patterns into individual machine operating modes. It produces an output similar to a typical industrial engineering time study but continuously, automatically and without an engineer in the section. It is relatively easy for a time-study engineer to identify the stop and end points of a cycle element and classify it by looking at the machine and glancing at a stop watch. The problem is that monitoring system hardware and software do not have these unique capabilities. Consequently, IDSS algorithms must automatically define the begin and end points of machine tasks and identify the task by recognizing patterns in kilowatt versus time data. However, many mines have file drawers of time-study type data that are not very useful. So, IDSS contains the knowledge representation subsystem (IDSS/KRS) to produce short reports containing only key information. This is difficult because mine environments continually change and information requirements differ for each management level. Consequently, IDSS/KRS must learn and adapt to new conditions in a dynamic mining environment. Western Fuels-Utah owns and operates the Deserado Mine, located about 19 km (12 miles) northeast of Rangely, CO (Upadhyay, 1988; King and Eros, 1988). One longwall and two continuous miner sections produce about 900 kt (1 million st) of coal annually for the Deseret Generation and Transmission Cooperative's 4000 MW power plant located near Bonanza, UT. Three mine monitoring systems control the underground mine, the preparation plant and the unit train load out. Pattern recognition IDSS/PRS produces a listing of begin and end times for each machine operating event as shown is Table 1.

Jan 1, 1991

By Bronson Stringham

The close area! relationship of Cretaceous or later intrusive porphyries to larger hydrothermal deposits of Pb, Zn, Au, fig, Cu, Mo, Hg,, and U of similar age in the Basin Range Province, was statistically shown in a recent paper (Stringham1) During the past year this study has been expanded to cover p11 of the larger hydrothermal deposits of similar nature occurring in the entire western United States. The sandstone type uranium deposits of the Colorado Plateau and Wyoming have been excluded since considerable controversy exists regarding their origin. The close relationship between intrusives in general and hydrothermal ore deposits has long been-recognized, but the association involving intrusive porphyry only, was suggested in 1954 when Sales concluded that the formation of porphyry may be an intermediate stage of activity between the development of granitoid rock and certain types of copper deposits. However: he applied this concept to only a few copper deposits. The relationship appears to be true also for a great majority of the hydrothermal deposits of the other metals mentioned above of Cretaceous and later age, at least in the western United States. This situation then leads to the conclusion then when exploring for similar types of hydrothermal deposits of the metals considered one may feel reasonably sure that if an intrusive porphyry of considerable size is. not present he may be facing much greater risk of finding an ore body than if a prophyry were presents Since, there are many intrusive porphyritic rocks which do not seem to be associated with hydrothermal deposit, it is believed that some distinct value can come from the recognition of intrusive porphyry which might be barren as well as the intrusive prophyry which might be productive This paper deals with that problem.

Jan 1, 1960

By H. Colijn

The problem of the freezing of moist raw materials, such as concentrates, in railroad cars during winter shipment has been a continuing source of both economic and operational trouble to the industry and to the railroad companies. The difficulties center around the discharging of frozen cargoes into the plant materials handling system. Because of cargo freezing, appreciable delays in car-dumping schedules occur each winter and cause additional expense for demurrage charges and for slowdown of plant operations. In one plant during one winter, a car dumper rated at 40 cars per day could dump only 3 cars per day in bad weather. Delays became so serious one winter, that 500 cars held in the yard became so badly frozen, that they were sent to the southern part of the United States to thaw after they accumulated an average of two months demurrage charges. These delays in car unloading become critical if unit or integral train concept is applied to the movement of raw materials. Anticipated savings in transportation costs through better equipment utilization are largely based on rapid loading and unloading cycles of whole trainloads. If freezing problems cannot be adequately solved, unit train operations cannot be operated to achieve the potentially large reductions in transportation costs. The freezing problem may tend to become even greater in the years ahead, because the unit train concept will allow the trains to run faster and consequently the heat loss will be accelerated due to the larger heat transfer coefficient. A compensating factor, however, will be the shorter travel time. Further, the sources of raw materials being mined are located farther north than before and the ambient temperatures during transit are going to be lower.

Jan 1, 1976

By Dennis S. Kostick

Soda ash is produced in over 39 countries by the Solvay ammonia-soda process or by mining natural sodium carbonate deposits. The total production of soda ash in 1980 is estimated at slightly over 29 million metric tons. Synthetic production accounted for over 75% of this amount with the balance of production originating from natural sources (either trona or sodium carbonate-rich brines) found primarily in the United States, Mexico, Kenya, and Chad.

Jan 1, 1981

By Michael Gay

Right in the heart of Boston Harbor lies Deer Island, where a ten-year, 6 billion dollar sewage treatment plant is under construction. The 9.5 mile long, 25.5' diameter Effluent Outfall Tunnel is the center piece of this program. A Robbins double-shielded TBM is currently driving this challenging tunnel some 400 feet below sea level. This paper will discuss the set-up and operation of this Tunnel Boring Machine in driving the longest single heading tunnel ever built in North America.

Jan 1, 1993

By Gerald W. Elger

Research at the Albany Metallurgy Research Center has shown that high-purity rutile can be produced from relatively low-grade ilmenite obtained from a massive rock deposit. Ilmenite is first smelted in an electric-arc furnace to separate the iron and produce a slag enriched in titanium dioxide. Titania slag mixed with a phosphate flux is then oxidized to synthesize rutile and form a phosphate-glass matrix which contains the impurities. Attrition scrubbing the treated slag in dilute solutions of phosphoric or sulfuric acid liberates the rutile, which is concentrated by physical methods. Tests show that synthesized rutile containing 95 to 97 pct titania responds to chlorination at the same rate as natural rutile.

Jan 1, 1973

By M. D. McInnis

The Jualin Gold Prospect is centered on Johnson Creek, approximately 40 air miles north-west of Juneau, Alaska. The property is on the southern end of the Kakuhan Range with Berners Bay immediately to the south and Lynn Canal to the west. The property is accessible directly by helicopter from Juneau or by float plane to the head of a 5.5 mile gravel road that begins on the north side of Berners Bay and terminates at the old workings of the Jualin Mine near the center of the property.

Jan 1, 1989

By Frank J. Markewicz

The expanding: demand for ilmenite for use in the manufacture of titanium pigments, the knowledge that much of this raw material comes from distant points and therefore has to include a heavy freight charge in the price of the delivered product, and the further knowledge that ilmenite occurs both in the crystalline rocks of northern New Jersey and also in some of the Triassic igneous rocks, were considerations which led to a search for ilmenite-bearing sands in southern New Jersey. That this search was successful is now history, and it is the senior author's privilege to state here that most of the credit belongs to his associates who did all of the heavy work of hand-augering for samples, and who made all of the heavy-mineral separations. We all are grateful to members of the Department of Geology at Rutgers and Princeton Universities for the use of equipment which enabled us to evaluate certain samples from our ilmenite exploration program. In addition, we wish to express our appreciation to many companies for their cooperation and for their permission to publish mineral and chemical analyses. We also acknowledge with much appreciation our debt to the geologists and engineers with whom we have had many lively and rewarding discussions relative to the ilmenite deposits.

Jan 1, 1958

The effect of the chemical composition of pulverized bituminous coal particles on their physical transformation during the initial stages of combustion has been investigated. The results suggested that cenosphere formation does not require extensive thermal decomposition of the coal particles. The vitrinites in the bituminous coal softened earlier and developed larger cenospheres than the othe macerals. The coal particles swell to a higher extent during combustion than in pyrolysis; however, the cenospheres formed in the former process experienced a higher extent of fragmentation. The development of microporosity occurred predominantly after the resolidification of the swelled char particles. The type of macerals originally in the coal did not significantly affect the microporosity of the chars. Conversely, the morphology and anisotropy of the chars were strongly dependent on the maceral composition of the coal.

Jan 1, 1986

"?irovski Vrh" Uranium deposit in Slovenia is type of mineralized sediments in ore bearing belts of deflected S-structure, in which the belt is less than 25% mineralized. Ore bodies of irregular small thickness, unreliably contoured, made difficult estimation of correct contours, which are necessary for design and exploitation works. The deposit was explored by vertical boreholes made at the surface and by boreholes fanned from drives. For the purpose of application of this estimation method, 1 m composites have been made in slices which were parallel to the referential belt plane. Estimation was made for 1,5m x 1,5m x lm blocks which do correspond to the size of the containers in the ore transport stage. Two variables have been used: the first, indicator of function (ore=1, waste material =0) and kriging method; the second, logarithmical content of Uranium and Minimum Mean Square Error Estimation (MMSEE) method. Based on estimated values of those variables, probability of ore quantity as well as Uranium content over determined cut-off were calculated for each block. Those two parameters enable determination of the most probable form of the ore body in ecah one metter slice. Estimation of sixteen small blocks in a large 1,5m x 1,5m x 1m block made possible estimation of ore quantity and its content for the determined cut-off, as well as categorization of exploration. This method is being used for estimation of ore reserves and planning of exploration operations. The described' methodology was tested in an exploitation block.

Jan 1, 1986

By Peter L. Comanor

At Getchell, Nevada a thousand tons per day mill for extracting gold from an ore containing orpiment and realgar was operated several years until early 1967. A cyanide process with a roaster was used in the processing of the ore. Mill wastes were contained in tailings ponds, in which the concentration of arsenic, currently, is one per cent or higher, Studies were conducted determining the effect of the tailing wastes on the Upper Sonoran vegetation of the area. Grid and line-intercept techniques were employed to obtain botanical informatics of the area surrounding the tailings ponds. Data of the per cent ground cover, species frequency, and plant vitality as a function of distance from the tailings ponds was collected. The data was compared to other botanical data collected from a control site outside the influence of the tailings ponds. In an attempt to isolate naturally occurring factors for varying plant communities from hose induced by factors derived from the close proximity of the tailings, soil cores were taken along the line-intercepts at intervals of 30 meters. The cores were analyzed for several compounds and elements needed for growth, or known to inhibit growth. Specific physical parameters of the soil samples were also taken. The paper describes the impact made by mill wastes containing large amounts of arsenic on the Upper Sonoran vegetation of the Getchell region. Described in detail are the techniques used to make the correlations between the plant communities and the influences of mill wastes.

Jan 1, 1974