Search Documents

By K. E. Hjelmstad

Solution mining operations often encounter difficulty maintaining adequate leach solution flow into the ore formation because of loss of formation permeability near the injection well. Permeability loss caused by swelling and breakup of clays and fine particle migration can often be the cause of the problem.

Jan 1, 1989

By H. E. Bonner

The recovery of fine coal has historically had limited success due to the intimate clay association on the surfaces of the coal particles. This clay presence has detrimentally affected conventional beneficiation techniques resulting in a recovered product containing unacceptably high concentrations of ash and moisture. An ultrasonically activated tray that operates in a continuous fashion has been developed that separates the clay film from each particle's surfaces. This separation is of sufficient duration to allow conventional beneficiation techniques to be utilized more efficiently.

Jan 1, 1989

By John S. Owens

The National Steel Pellet Project and the Butler Taconite Project are operated by The Hanna Mining Company in the vicinity of the towns of Keewatin and Nashwauk, on the western Mesabi Range. Production began in 1967, after seven years of exploratory and development diamond drilling and reconnaissance magnetic surveys, Previously, direct shipping hematitegoethite ores and gravity concentrates had been produced in the area from numerous open pits and several underground mines since the start of the century. Total shipments of these oxidized ores amounted to more than 200 million tons, but at the present time such reserves are nearly exhausted, and there are no mining operations in the Keewatin-Nashwauk area except at the two taconite projects. The locations of all of the present taconite operations on the Mesabi Range are shown in Figure 1, extending for a distance of about seventy miles from the Butler plant to the Dunka River area. The Butler and National plants have a combined rated capacity of 4.4 million tons of pellets. Their reserves cover a combined strike length of about eight miles on the Biwabik iron formation. All of the intervals between present taconite operations on the Mesabi are potential sources of additional magnetic taconite; in particular, exploration and economic studies have been carried out by Jones and Laughlin Steel Corporation in the Biwabik area between Aurora and Virginia, and by Pickands Mather and Company in the Hibbing area. However, west of the Henna and Butler holdings, it appears unlikely that magnetic taconite exists in commerical quantities at economic depths due to extensive oxidation of magnetite to hematite.

Jan 1, 1968

By D. L. McClure

Gold mineralization at the Colosseum Mine is submicroscopic and associated with pyrite. Pyrite occurs in breccia clasts, replacing dolomite, in crackle breccia veinlets with traces of quartz, and as disseminations in two small, interconnected intrusive pipe complexes of rhyolitic felsite and breccias of felsite and wall/country rock. Breccia types grade from felsite plus wall rock of Pre-cambrian gneiss to cross-cutting breccias "of felsite, gneiss, and Paleozoic sedimentary rocks that are in contact with the Precambrian gneiss terrane one-quarter mile (40Om) southwest of the Colosseum pipes. Mineable reserves are estimated to be 8 million short tons (7.3 million metric tons) at 0.074 troy ounces of gold per short ton (2.3 g/metric ton) at a cutoff of 0.03 troy ounces of gold per short ton (1.0 g/metric ton).

Jan 1, 1988

By B. Spigarelli

Carbon dioxide sequestration by conversion to carbonates has become a promising option for CO2 storage. Experiments were conducted to determine the feasibility of CO2 sequestration at ambient conditions using a Ca-rich industrial waste in a carbonate solution. The Ca-rich industrial waste used in this study was lignite fly ash. Fly ash was chosen because it is cheap, available near large CO2 point sources, already in powder form, and reactive due to amorphous properties. In the experimental set-up, CO2 absorption was inferred by monitoring feed and exhaust gas CO2 concentrations. The addition of an alkali to a fly ash-distilled water solution provided a 50% increase in CO2 absorption of the solution. Absorption time also increased by 50% compared to a fly ash-distilled water solution. TGA analysis was used to determine the extent of CO2 sequestration in the carbonate form. At a liquid to solid ratio of 20:1, the conversion of ?free? calcium to carbonates was 75%. A CO2 balance on the system concluded that at the current operating conditions 42% of the total CO2 fed to the system was sequestered in the carbonate form. SEM-EDS analysis of the fly ash particles before and after reaction with CO2 indicated that the carbonate compound being formed was calcium carbonate. The analysis identified rhomboidal structures on the surface of the fly ash particles after reaction with CO2, but not before. These rhomboids are characteristic of calcium carbonate formation and they had higher Ca, C, and O concentrations than the host spheres, suggesting calcium carbonate formation.

Jan 1, 2012

By Julian Malnic

The nascent marine mining sector appears to be now at a point of critical mass with the prospect of mining seafloor massive sulphide deposits at some time in the coming few years an inevitability. Julian Malnic makes comments from his experience base as an entrepreneur and founder of Nautilus Minerals Inc. in 1995 and will speak from an independent viewpoint of the commercial setting of the status quo of the proto-industry and the major factors likely to have major influence over its future. The presentation questions these factors and the role they will play. Do we need metals from the oceans? Understanding the competing and established terrestrial sources of each commodity is essential in comprehending how a marine competitor can profit. What are the rates of discovery for marine minerals? At what point will marine explorers start to impact the terrestrial copper and zinc exploration sector? The advance of technology is important in finding, imaging and mining SMS deposits, but which new technologies offer the advantage to mining in the ocean and which to mining on the land? Several competitors have now joined Nautilus as competitors to this global pioneer of SMS exploration/production. The membership of the major miners in the marine sector is growing steadily with important relationships developing but many have not put a toe in the water yet. A path of increasing width is opening to commercialization of SMS miners but crusts and nodules, as bearers of copper ? also found in SMS, and nickel ? also found in widespread nickel laterite deposits on land, are unlikely, in this perspective, to be winners this century unless highly valued minor metals are targeted.

Jan 1, 2008

By M. M. Rajkovich, J. J. Zaluski, S. J. Gardner

The telephone rings at 3:20 a.m. and an exasperated voice on the other end says, “There’s been a mine explosion at Mine No. 5 and we have not heard from three units of men!” Twenty-three minutes later, the phone rings again and another panicked voice says, “There’s something wrong at the slurry impoundment, the pool level has just dropped five feet and we’re trying to figure out what’s wrong!” Thirty minutes later, the mobile phone rings and an excited security guard says, “We have reports of thick black water running down both the right fork and left fork of Straight Creek and both seem to be rising in the banks!” As if this isn’t enough excitement, the mobile phone rings again and a stressed company official says, “I just heard a report that black slurry is running out of the portals of XYZ Company No. 2 Mine, which is adjacent to our No. 5 Mine!” Is this all some kind of dream or nightmare? More importantly, however, if this could happen, what on earth do you do? Although we all like to think that “It can’t happen to me,” we all must admit that mine explosions do happen, slurry impoundments can rupture and creeks can flood with black water causing damage to others, including competitors. Your response must be quick, cool-headed, calculated and effective. This paper will examine the issues, concerns and ramifications of this hypothetical “disaster” and then present a systematic crisis management response. While each situation is different, there are general guidelines for forming an effective plan of action.

Jan 1, 2003

By Raphael G. Kazmann

The predicted warming of the earth's surface, presently the subject of much debate, controversy and legislation, is based on what is termed "the greenhouse effect." This is the result of the property of certain atmospheric gases. These gases allow the passage of radiant energy to the earth's surface and reflect back, to the earth, the infrared radiation given out by the heated surface. Physicists have computed that if there were no greenhouse effect the average temperature of the earth, now about 15° C (60T), would be close to -18° C (OT). Just what gases have produced this salubrious effect? Water vapor is the most important. Then come carbon dioxide, methane and a number of minor constituents of the atmosphere, both natural and man-made. Climate change, its cause and its impact on human activities have been the subject of scientific and historical study for more than a century. Recently, some scientists have concluded that if the man-made increase in the carbon dioxide and other greenhouse gases continues, by the late 21st century the earth's global average temperature will rise between 2° to 8° F. This temperature rise would cause the water in the oceans to expand and the massive polar glaciers to melt. In 1980, it was predicted that the sea level would rise 7.6 m (25 ft) by the late 21st century. By 1985, the predicted rise was 1 m (3 ft); and by 1989, it was 0.3 m (1 ft) (Jastrow, Nierenberg and Seitz, 1990). Agricultural scientists have pointed out that an increase in atmospheric carbon dioxide would enhance biological growth including the production of foodstuffs.

Jan 1, 1992

By J. D. Megeath

In the October 1988 issue of MINING ENGINEERING, J.G. Wargo's paper discusses the problem of measuring and analyzing permeability, porosity, and fracturing in its relation to in situ leaching of disseminated gold deposits. This paper made me suspect that a good deal of information and analysis may have been done on this in reverse in the petroleum industry. Some years ago, I was involved with the US Geological Survey in a project studying the Devonian shale of the eastern United States. The Devonian shale contains gas deposits that have the characteristic of slowly seeping gas over a very long time period. To understand the rate of seepage, considerable study and analysis was done on the interrelationship of poros¬ity, permeability, and fracturing. The purpose was to find out how and why the gas could escape in the varying rates found in wells throughout the formation. It strikes me that this is the mirror image of the problem faced in attempting to understand how a cyanide solution will travel into a deposit. To possibly invent our own personal wheel a little faster, I would suggest a look at the work done on the Devonian shale. Some of it is contained in "Estimates of Unconventional Natural-Gas Resources of the Devonian Shale," US Geologi¬cal Survey Open-file Report 82-474, 1982, and "Additional Data for the Estimates of Unconventional Natural-Gas Re¬sources of the Devonian Shale," Open-file Report 83-676, 1983. It is entirely possible that some of this previous work could shorten the time required to make in situ leaching of dissemi¬nated gold deposits a profitable technique.

Jan 1, 1989

By Hal McVey

Introduction The role of marketing in the minerals and mining industry takes on different degrees of importance depending on the commodity, but nowhere are sales and marketing more important than in industrial minerals. This article compares industrial minerals marketing with the marketing of other mining and mineral products. Marketing in Mining Some broad generalizations on the marketing of industrial minerals in relation to other mineral products can be made without getting bogged down with exceptions to generalizations. Two totally different areas of mineral production are crude oil and natural gas, and metals, including ores and concentrates. Although these commodities are the basis for two completely different industries, they share two things in common from a marketing standpoint: • Their value per unit volume is usually high enough so that they can be transported great distances. • Their specifications are readily definable and, therefore, the quality of a standard product from a production run can be communicated by stating certain chemical and physical features. This permits sales to be consummated by telephone, telex, and letter, without the need to pretest the products under use conditions. In regard to the first item, industrial minerals, as opposed to oil, gas, and metals, are in most instances site specific. Location of the point of production in relation to the point of use is of paramount importance based on a generally lower unit to volume value. This means that transportation is a major factor, with the cost of getting the mineral to market commonly exceeding its f.o.b. value. Coal marketing has many characteristics in common with industrial minerals. Coal sales can es-

Jan 11, 1983

By Charles Fisher

When considering the biodiversity of fauna endemic to hydrothermal vents or hydrocarbon seeps one must consider not only the numbers of unique species, but also the physiological diversity (and potential biochemical/physiological uniqueness) of the fauna. The deep ocean ridge system is home to some of most extreme animal habitats found on Earth. In addition to the high pressure, low temperature, and lack of light characterizing the deep-sea in general, hydrothermal-vent environments are characterized by toxic chemicals and temperatures that would be hostile to most other animal life. Perhaps even more challenging than the absolute levels of chemicals, dissolved gases, and temperature with which vent animals contend are the extreme gradients in time and space of all of these parameters. For example, temperatures around some vent animals can fluctuate from ice-water to hot-tub levels over seconds and can exceed 350°C only inches away. Specially adapted animals not only tolerate these conditions, they often thrive under them. As a result, the biomass of many deep ocean ridge ecosystems rivals that of coral reefs and tropical rain forests. In the Gulf of Mexico, hydrocarbon seepage through the sea floor driven by salt tectonics results in environments that are geologically very different from hydrothermal vents, but are geochemically similar enough that closely related animals are found in the two habitats. This includes seep mussels, clams, shrimp, worms, and other animals whose close relatives are found in hydrothermal vent environments. Although many aspects of the biology of the animals from the two environments are very similar, there are also significant differences in their life histories and physiologies that reflect the fundamental differences in the geology of their habitats.

Jan 1, 2008

By J. C. Norman

The boron review arrived too late for the June issue. The United States was the world's largest producer and consumer of boron compounds during 1993. Boron mineral concentrate and chemical production in the United States totaled an estimated 958 kt (1.05 million st), yielding 526 kt (580,000 st) of B203, according to the US Bureau of Mines. Estimated value was $322 million. This level of production was about 5% less than 1992 revised production figures. The United States continued to provide essentially all its own boron 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 1993 was 900 people, about the same as in 1992. That was down from 1988 levels of 1250 people. Total world production of boron in 1993 was about 2.5 Mt (2.75 million st), yielding about 1.2 Mt (1.3 million st) of B203. World production in 1993 was about equal to revised 1992 levels. Production United States In 1993, mines and processing operations in southern California were the only domestic sources of boron mineral concentrates and chemicals. Domestic producers, in order of quantity of production, were: • US Borax and Chemical Corp., which operates an open pit kernite and tincal mine at Boron, CA, producing boric acid and borax products, • North American Chemical Co., which produces boric acid and borax products as coproducts from chemical operations at Searles Lake, CA and • American Borate Co., which produced small amounts of colemanite and shipped from inventories from its operation in Death Valley, CA.

Jan 1, 1994

By J. D. Megeath

In the October 1988 issue of MINING ENGINEERING, J.G. Wargo's paper discusses the problem of measuring and analyzing permeability, porosity, and fracturing in its relation to in situ leaching of disseminated gold deposits. This paper made me suspect that a good deal of information and analysis may have been done on this in reverse in the petroleum industry. Some years ago, I was involved with the US Geological Survey in a project studying the Devonian shale of the eastern United States. The Devonian shale contains gas deposits that have the characteristic of slowly seeping gas over a very long time period. To understand the rate of seepage, considerable study and analysis was done on the interrelationship of porosity, permeability, and fracturing. The purpose was to find out how and why the gas could escape in the varying rates found in wells throughout the formation. It strikes me that this is the mirror image of the problem faced in attempting to understand how a cyanide solution will travel into a deposit. To possibly invent our own personal wheel a little faster, I would suggest a look at the work done on the Devonian shale. Some of it is contained in "Estimates of Unconventional Natural-Gas Resources of the Devonian Shale," US Geological Survey Open-file Report 82-474, 1982, and "Additional Data for the Estimates of Unconventional Natural-Gas Resources of the Devonian Shale," Open-file Report 83-676, 1983. It is entirely possible that some of this previous work could shorten the time required to make in situ leaching of disseminated gold deposits a profitable technique.

Jan 1, 1990

By Jean Rainville

Gold was first discovered in the central region of French Guiana in the mid 1860's. Production was based strictly from placer mining of the various rivers in the region. At the moment, a number of companies are actively engaged in hard rock gold exploration, concentrated in the northern and central regions of the country. The Franc-Or/BRGM joint venture in the Sophie-Repentir region of Central French Guiana offers an exceptional opportu­nity for the discovery of one or more million-plus ounce deposits of gold owing to a highly favorable structural setting in Precam­brian greenstones that host several known vein gold occurrences, some of which appear to occur near the border of a potassic granitoid intrusion. At this point in time, based mostly on predecessors' work, mineable reserves could be estimated to be in the 500,000 ounces range over the length of the property. The exploration campaign under way has the objective to delineate probable reserves of at least 2 million ounces that could be mined by open pit mining methods in the area. The program should be completed in the next 18-24 months. In order to efficiently and effectively evaluate this very large property area, all of the necessary camp, mechanical and drilling equipment has been purchased and is being transported to the property. Most of that equipment was purchased in Canada. The first drill target is the Repentir sector because of its access and the amount of detailed work that has been done by BRGM on that concession, but geological evidence suggests that many areas on the property could offer even more potential.

Jan 1, 1995

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. Krizek, A. H. Ditto

INTRODUCTION The Carr Fork property is situated in the Bingham Mining District located on the east slope of the Oquirrh Mountain range in Utah. The mine is adjacent to and lies west of Kennecott's Bingham Pit some 25 miles southwest of Salt Lake City. The Bingham Mining District contains one of the largest copper reserves on North America. Mineralization is associated with the Bingham stock which intruded through some 16,000 feet of sedimentary formations. Mineralization and a1teration zoning was developed radially from the Bingham stock with lower grade disseminated copper mineralization centrally located in the stock and adjoining quartzites. In addition, several garnetized limestone beds abutting the stock were also well mineralized. These skarns will be Carr Fork's initial mining target. Of the several limestone beds, only two, the Yampa and the Highland Boy have significant commercial interest at present. These beds which are 50 feet to 150 feet thick and are separated by 200 to 400 feet of quartzite were highly folded, thrusted and faulted, resulting in a dip variance from 20" to vertical. The predominant dip, however, is between 20" and 45" from horizontal. Quartzites surrounding the limestone beds were subjected to the same degree of tectonic activity with resultant intense fracturing and stress relief. The limestone beds which have a higher elastic modulus and which also experienced fracture healing during mineralization appear to have greater competency and strength than the quartzites. Four shafts nominally 3500 feet deep will provide access to the mine which will be a highly mechanized trackless operation, designed to produce 14,000 tons per hoisting day. First production is scheduled for the last quarter of 1979.

Jan 1, 1977

By Randhir Sehgal

If the primary purpose of a control system is to assure a fixed-quality product at maximum yield, the real issue involved in control of the fine coal cleaning circuit in a plant is to demonstrate that control is technically feasible and economically beneficial . This paper suggests that it is not easy to do so in most cases. Fine coal, defined here as the 28 mesh x 0 fraction of the plant feed, is generally cleaned using a combination of hydrocyclones and flotation. Both of these processes are relatively insensitive to changes in operating variables. Further, the fines fraction general 1 y forms no more than 20% of the plant feed and, at times, is as low as 10%. The instruments to measure flow rates, densities, and product qua1ity (ash, sulfur, etc.) are not sufficiently accurate to allow effective responses to changing state variables and product quality. It is sufficient to run the fine coal circuits at maximum recovery, and the control of product quality and optimization of yield should be achieved by controlling the coarse coal circuits and measuring the quality of the entire clean coal leaving the plant. This contention is made with particular reference to U.S. plants cleaning coal for the utility industry and should be viewed in this context only. It is explicitly admitted that this strategy is mathematically non-optimal in the sense that all size fractions are not necessarily cleaned at equal elementary ash, and would result in a loss of yield. However, under the conditions of conventional coal cleaning practice, this is a sensible approach.

Jan 1, 1988

The most important event affecting the United States coal industry in 1993 was the strike by the United Mine Workers of America (UMWA). This was a series of selective strikes, beginning with a strike against four Peabody Holding affiliates on Feb. 2, following unsuccessful contract negotiations between the UMWA and the Bituminous Coal Operators' Association (BCOA). Although that strike ended on March 3, the failure to reach a new contract agreement led to walkouts at several Midwestern mines on May 10. During the summer, the strike expanded to include mines of 13 companies in seven states including Ohio, Pennsylvania, Illinois, Indiana, Kentucky, Virginia and West Virginia. About 17,000 miners were idled during the strike. As the prospects for a settlement diminished, the Secretary of Labor appointed a federal mediator. The mediation resulted in a five-year contract. In addition to increases in wages and pensions, it was agreed that 60% of new job openings would be filled by laid off and active UMWA miners. In return, companies won the right to establish more flexible work rules and scheduling of miners. While some health care benefits were expanded, the agreement established a new health care system that was designed to reduce costs. Preliminary Energy Information Administration (EIA) data indicate that US coal production fell by 5% in 1993, to 859 Mt (947 million st) (Table 1). The strike was one of the primary causes of the decline in production. Another significant cause was a 27% decline in coal exports. Also, a very small displacement of domestic coal production resulted from a rise in coal imports.

Jan 1, 1994

By Ronald I. Fuller

Core Laboratories, a division of Western Atlas International, maintains laboratories in all energy-producing areas of the United States, as well as in many foreign countries. Central to laboratory operations has been the incorporation of computers and computer software. Core has developed a mu1tiuser Laboratory Information Management System (LIMS) , which is currently installed in numerous company sites in the U.S., and is now undergoing installation in Canada. In addition, Core has provided custom soft ware to contract laboratories which Core operates on behalf of mining firms. The software development was done under the direction of the author in Denver, Colorado, and Casper, Wyoming. The intent of this paper is to pass some of the practical experience gained by our efforts on to those who wish to utilize computers more fully in the laboratory setting. The product of analytical laboratories is numbers. Nothing else comes from our work. We deal in information about samples. It is then reasonable to assume that the computer would be central to a laboratory operation. The hard part is to initially define what kind of computer the lab operation needs. The choices today can be very complex, and almost every hardware salesman is full of bad advice. Even the people in your own information services department may hold divided opinions. Since the advent of the personal computer, we have lived with a polarized data processing community. The PC boys consider their machines equal to any challenge, while the "save the mainframe" crowd view the PCs as limited toys that are only good for the things that clutter up a real computer. Management tends to lean toward whatever costs the least.

Jan 1, 1989

By Robert C. Jones

The Henderson Mine, a new large scale underground development, is being developed by AMAX. The mine site is located about 50 miles west of Denver, Colorado, adjacent to the east side of the Continental Divide. The mine's three access shafts are in a narrow alpine canyon at an elevation of 10,400 feet. The ore body of molybdenite is to the south of the shafts, 3,000 feet below the surface of nearby Red Mountain. The ore extends over 800 feet vertically and is about 1,700 feet by 2,200 feet horizontally. The eastern and southeastern boundaries of the deposit are still to be defined at the present time. Development mining is advancing at the mine site on a three shift, seven-day basis at the rate of about 2,000 feet per month. About twelve miles of heading have been driven at the present time, and work to sink No. 3 Shaft has started. Development mining was begun in 1967 with the sinking of No. 1 Shaft. This shaft is fully concreted, 23 feet in diameter and 2,441 feet in depth. It is the mine ventilation exhaust conduit. It is also used for development muck hoisting, stand-by mine water pumping and secondary access to the 8,035 foot level. This level is the mine exhaust ventilation level and was mined principally by conventional rail mining methods. From this one station at the 8,035 foot elevation a 5% ramp was driven to the initial production horizon at 8,100 feet with diesel rubber tired mining equipment. Subsequent mining has been entirely by mobile diesel equipment at the mine site.

Jan 1, 1974