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By Orris C. Herfindahl

Every few years we are treated to a battle over trade policy when the Reciprocal Trade Agreements Act comes up for consideration. In 1962 it is especially appropriate to consider the problem of mineral import -policy and the closely related problem of general import policy, for this year's struggle is different from those of the past in two ways. First, proposals have been made which are a substantial departure from past trade agreements legislation, and second, the formation and growth of the Europe Economic is Community may have an important bearing on the kind of legislation that is adopted. But this anticipates what is to come later. My task is to examine the problem of mineral import policy, although we shall find soon enough that general trade policy must be considered in order to get an indication of what is in store for minerals.

Jan 1, 1962

By Lake H. E.

The request to participate on your theme panel was accepted with some reluctance but indeed as an honor. My subject was outlined to cover 'Energy Resources - both nuclear and conventional' as related to your theme 'Minerals - Treasure Trove of the West'. This is indeed quite an order and I hope you will forgive me for concentrating mainly on the nuclear-uranium portion with brief references only to conventional fuels some of which will be covered in detail later in your conference. In regard to Uranium, I am speaking on the fringe of the area containing half the uranium reserves in your country and no doubt to many who are very conversant with knowledge of these resources. Nevertheless since our two countries have been very closely allied in both nuclear developments and uranium supplies I hope an exchange of information may be mutually beneficial. Concentration on the nuclear fuel resources is I hope understandable as nuclear energy is the coming source of power which will augment the rapid demand in the industrialized countries and provides hope for economic power in many of the more underdeveloped countries. The situation regarding conventional fuel resources is more widely known and their expanding future revolves around production cost reductions, research into diversified uses, plus more assurance of imports from countries less effected by international controversies determining export policies.

Jan 1, 1967

By B. K. Cantrell

The use of diesel equipment in underground coal mines is controversial because "whole diesel exhaust" is regarded as "a potential occupational carcinogen" by the National Institute for Occupational Safety and Health (NIOSH). Threshold limit values (TLVs) are recommended for the gaseous pollutants; CO, CO2, NO, NO2, SO2' and some hydrocarbons emitted in diesel exhaust. There is, however, no TLV recommended for diesel exhaust aerosols (DEA) nor is there a standard method for sampling these aerosols. The University of Minnesota and the Bureau of Mines have collaborated to develop a personal diesel exhaust aerosol sampler (PDEAS) which utilizes size selective, inertial impaction and gravimetric analysis. During the field tests of this sampler, numerous air quality measurements were conducted in underground coal mines using diesel equipment. The objective of this report is to present these data and to assess the impact of diesel face haulage equipment on mine air quality.

Jan 1, 1991

By R. C. Milici

The primary factors that determine the marketability of coal from various supply centers in the U.S. are coal quality and supply; i.e. low sulfur, moderate- to high- Btu coals have large market areas when compared to less expensive but poorer quality coals. Price is the major factor in the competitive marketing of similar coal products. Good quality, (moderate- to high- Btu, low sulfur) coals from the Powder River and central Appalachian basins are marketed over large areas of the country, and central Appalachian coal is widely distributed in foreign markets, primarily as coking coal. In contrast, poorer quality bituminous coal (low calorific value and/or high sulfur) from the Illinois Basin, northern Appalachian Basin, and lignite from the Gulf Coast is marketed in or near the States in which it was mined even though the price at the mines may be lower than mine prices for central Appalachian coal. Widespread distribution of sub-bituminous Powder River Basin coal is enhanced by its exceptionally low mining costs, which offsets transportation costs to distant markets.

Jan 1, 2001

By Daniel B. Brimhall

The research presented here was initiated to investigate the role of atmospheric oxygen in the leaching of copper waste dumps. The problem of increasing the recovery rate of copper from these dumps is or great importance considering there are by conservative estimate in excess of fifteen billion pounds of copper located in dumps in the western United States. At this time, there is an increased interest in recovering copper from these dumps on a large scale. Large tonnages of low-grade material are being placed on the waste dumps of most copper mining operations in the western United States each day. The size of these dumps ranges from 5.5 million tons at Mineral Park, Arizona, to 4 billion tons at Kennecott's Utah operation (1). Leach solutions are recycled and contain ferrous and ferric sulfates. Large quantities of dissolved aluminum, magnesium and calcium salts may also be present. To this solution make up water is added to maintain the solution inventory and sulfuric acid is added for pH adjustment. Iron is introduced into the leach solution by the dissolution of the iron-containing sulfide and oxidized minerals present in the ore deposit. In addition to the iron from dump leaching, iron is also introduced during the precipitation process when the pregnant solution is passed over metallic scrap iron if cementation is used to reduce the copper in solution.

Jan 1, 1972

By Meisam Ghiasi, Mohammadreza Khalesi, Mahmoud Abdollahy

In the current research, isothermal experiments of kinetic analysis were performed at different temperatures (800–1050 °C) and particle sizes (885 to 10,763 μm) to investigate the calcination kinetics of high-purity limestone. Thermal analyses were carried out in a zirconia crucible, 1 cm in height, for different temperatures and particle sizes. The reaction rate coefficients were varied in the 2.2 × 10−5-1.62 × 10−3-m0.6.s−1 range. Moreover, various isothermal kinetic analysis methods were applied to assess the decomposition mechanism and the calcination function governing the process. The modified shrinking core model was found as the best representation of the high-purity limestone kinetic data. The activation energy was evaluated using the Arrhenius curve, and an average value of 86 kJ.mol−1 was obtained.

Sep 15, 2020

By James P. Cooney

What is required for the mining industry to grow and prosper in a politically challenging world? The answer to this can be summarized as “the industry’s three priorities.” The first priority is gaining access to the world’s mineralized jurisdictions. The second is establishing a measure of security and predictability in government treatment of mining. Confidence in the stability of the fiscal and legal framework within which mining operates is necessary to encourage the investment of large amounts of capital in mine development. The third priority is sustaining the industry’s welcome during the long term in those jurisdictions worthy of investment.

Jan 1, 1996

By Frederick C. Moore

This paper describes the original planning which actually resulted in the opening of a new aggregate plant located in central New York State. This plant, which is now named the Skaneateles Plant of The General Crushed Stone Company is unique in that the plant itself is a departure not only in design but in concept of operation from the normal aggregate plant the company has operated in the past. Whether or not the concepts which resulted in the Skaneateles Plant are economically feasible remain to be proven by the next few years of operation. By way of background data about our company which will help set the stage for this presentation, we currently operate seventeen stone quarries in the states of New York, Pennsylvania and Virginia. These quarries range in size from 200,000 tons per year to 1,500,000 tons per year with a total annual stone production of approximately 7,500,000 tons. We also produce about 1,250,000 tons of sand and gravel at six sand and gravel plants, 300,000 cubic yards of ready mix concrete, 1,500,000 tons of bituminous concrete, aglime and other minor construction materials. In many cases we are our own best customer consuming a large percentage of the total production of our own aggregates in our various ready mix and blacktop plants. Up to the concept of the Skaneateles Plant our operating facilities have been of the permanent type as opposed to the moveable or portable type plant. The steps involved in the case history of Skaneateles will begin with the basic economic requirements, market research, geologic surveys, land acquisition, zoning and financing and carry through to the final design and construction. We will attempt to show what some of the problems were, how we interpretted them and how we proceeded to solve them. The current results are apparent and can be analysed. The success of the total concepts of the Skaneateles Plant remains for future analysis.

Jan 1, 1968

By R. J. Nankee

Coal is our most abundant, low cost energy resource. Expansion of its use is being challenged due to "SO2 emission" regulation with even more restrictive legislation pending. High quality coal reserves are becoming more limited due to greater use in recent years. Aids to allow more use of coal in today's environment include beneficiation of coal before combustion and scrubbing the emissions from coal during combustion. Dow's efforts to help meet these challenges by beneficiating coal include true heavy media gravity separations with chlorinated solvents and liquid/liquid partitioning processes and "Dow Solvent Recovery Technology" to recover the solvent from product (or floats) and rejects (sinks), The objectives of the efforts to clean coal are to reduce sulfur and ash. In this paper, the solvents will be described; a general flow diagram presented; some of the results on upgrading various coals will be described, and projected costs of full-scale plants using chlorinated solvents will be compared to conventional cleaning plants.

Jan 1, 1985

"Cast blasting is the primary means of overburden displacement in a surface coal mine. It serves two purposes; fragmenting the rock and throwing it directly to its spoil pile using explosive energy. Increased throw minimizes costs by reducing the amount of material that needs to be rehandled. Prior studies have shown that by only changing blasthole timing with the same blast design, fragmentation and throw alter. It is necessary in cast blasting to optimize both fragmentation and throw, since larger fragments will require more wasted energy to throw the same distance. In an operating mine in Georgia, an optimum interhole delay for fragmentation has been found by studying timings from 0 millisecond (ms) to 45 ms. Instantaneous timing between holes increased the throw by more than 31 m (100 ft), but fragmentation was poor. Shock and detonation wave collision is a potential reason for this increased throw.Explosives are utilized extensively by the mining industry in order to break rock, as either ore or overburden, for hauling, loading and crushing. An effective production blast strives to achieve optimum rock fragmentation in order to increase the efficiency and reduce the costs of those downstream operations, while simultaneously meeting environmental regulations. The goal of blasting with respect to fragmentation is, according to Hettinger (2015), “to decrease the average particle size of the fragmented rock without overly increasing fines or, in other words, improve fragmentation.”Additionally, the distance the rock is transported by the explosive energy from the blast, also known as throw, can increase efficiency by reducing the amount of material that is rehandled by mine equipment. The primary situation in which this is desirable is the cast blasting of overburden across the narrow pit of a surface coal mine. A key variable in a blast design pattern that can be manipulated to optimize both fragmentation and throw is delay timing between detonations. The invention and increased utilization of electronic detonators have allowed for precise delay timings to be used between rows, holes and even multiple primers within the same hole. These recent developments in the blasting community have also provided an opportunity to investigate whether or not the mechanism of shock or detonation wave collisions caused by short timing delays are responsible for any increased fragmentation or throw. This experiment attempts to demonstrate if an increase in throw can be achieved while maintaining optimum fragmentation."

Jan 6, 2017

By Jr. Smith

Silver-gold ratios were studied at the Tayoltita epithermal vein deposit using channel sample, channel sample line, stope, ore body and vein sample populations. The ratios are highly variable among individual channel samples (25:1 to greater than 500:1) with both high and low values randomly distributed within ore bodies and veins. Whole vein ratios for the fourteen most important ore producing structures range from 44:1 to 105:1, and show zonal distribution relative to two small granitic stocks, low values closest to the intrusives. The zoned nature of the deposit suggests that the stocks, apophyses of an underlying batholith of Late Eocene age, were the heat engines which powered the hydrothermal system responsible for ore deposition.

Jan 1, 1978

By H. J. Hutson

BRS, Inc. has utilized Carlson's Natural RegradeTM software to design the reclamation and stabilization of abandoned open pit uranium mine spoils, AML Project 16N, located in the Gas Hills Uranium District in central Wyoming. This work was completed for the State of Wyoming's Abandoned Mine Land Program (AML) on preSMCRA (Surface Mining Reclamation and Control Act) sites for which no reclamation obligation existed. The project successfully stabilized an eroding spoil dump, enhanced the local view shed, created habitat diversity and provided a significant source of fill material for open pit highwall hazard mitigation efforts. Additionally, the project served to evaluate innovative reclamation design methods, engineering software and grade control technology. This project was nominated for a National Association of Abandoned Mine Land Programs award by the State of Wyoming. The results of this project will be presented as a case history of the Natural RegradeTM approach to surface mine reclamation. Based on the successful application of this new mine reclamation technology on the AML 16N Project, reclamation designs for spoils associated with planned underground uranium mine operations at the Velvet Mine in the Lisbon Valley Uranium District of Utah for Uranium One USA, Inc have been prepared and will be presented. Critical elements will be the encapsulation of unsuitable materials, long term hydrologic stability, and sequencing and staging of ore and mine waste for final reclamation surface construction. The goal of the Uranium One Velvet Project will be to apply best available technology to reclamation planning and fully integrate the reclamation design with the mine planning. Benefits of the approach should include improved public and regulatory perception of the project, facilitate mine permit approvals and the eventual timely release of reclamation bonds, as it is anticipated the stable landform created through this process will result in more rapid stabilization of the site to pre-mine geomorphic conditions. NATURAL REGRADETM CASE STUDY AML Project 16N, D-9 and K Pit Reclamation Project, is located in an intensely disturbed area of the West Gas Hills Uranium Mining District in Fremont County, Wyoming. The overall design calls for the placement of approximately 7 million cubic yards of backfill materials in the D9 and K Pits, imported from adjacent mine spoils including the Central Spoils, and from local highwall excavation. Figure 1 shows the location of the Central Spoils excavation area, as well as the D9 and K Pits fill area. The entire project is located on public lands administered by the Bureau of Land Management, Lander, Wyoming District Office. No access controls are in place at the abandoned mine sites. The public lands are administered under a multiple use land policy including grazing of range land, public recreation, active mining and exploration, and oil and gas. The project site is located along Fremont County Road No. 5, which is a moderately well traveled road. Reclamation of the numerous and large abandoned open pits in the Gas Hills Uranium District has reduced the risk of death or injury to the public. Site History and Background The Gas Hills Uranium District was mined by multiple companies during the period from 1955 to 1981. The uranium was hosted in the Wind River formation, a sequence of soft sedimentary layers of interbedded sandstone, clayey shales, and conglomerates. Uranium was precipitated out of ground water in classic roll front deposits, which are found from very near surface to depths greater than 400 feet. Prior to the enactment of the Surface Mining Control and Reclamation Act of 1977 (SMCRA), very little reclamation work was performed when mines were abandoned or closed. The State of Wyoming Abandoned Mine Lands Program has worked to mitigate hazards associated with large open pits, control migration of unsuitable materials and restore watershed functionality of lands in the district. Additional reclamation is being performed by mining companies on bonded lands. Figure 2, Gas Hills Uranium District aerial photograph, shows the extent of the mining disturbance in the district. [ ] Project Hazards and Concerns The purpose of AML Project 16N is to mitigate hazardous conditions and risk to the public associated with open pit highwalls and toxic, acid forming, and /or radioactive mine waste materials. The D9 and K Pits are contiguous open pits characterized by an 8,800 foot long hazardous highwall that averages over 200 feet tall. In addition to the physical hazard presented by the highwall, the project addresses

Jan 1, 2009

By J. S. Rapp

This report is based on existing reports and recently gathered field data. It discusses mineral resource potential of Tertiary playas in the Fort Irwin region. An estimated 1.3 million tons of measured salt "reserves", and 20 million tons of indicated salt resources, have been identified north of the fort. Other indicated resources include 300,000 tons of celestite, 800,000 tons of gypsum, and 10 million tons of selenite. Zeolitic tuff was mined south of Fort Irwin from 1978 to 1984, and unexplored occurrences are widespread. Calcium-bentonite is mined near Barstow, and more may exist, including valuable sodium-and lithium-based bentonites.

Jan 1, 1992

By Yongsik Jeong, Kwangmin Kim

Most tailings storage facility (TSF) failures occur in active, upstream-type TSFs, often due to extreme and unexpected weather conditions—specifically, heavy rainfall and strong winds. This case study of a TSF in southern Arizona examines the use of the optimum safe beach distance (Doptimal, the optimum distance between the crest and decant pond) as a tool for monitoring geotechnical stability and reducing catastrophic failures. A digital model of the TSF was used to determine the critical beach distance (Dcritical) under normal weather conditions, and Doptimal was then determined by adding incremental distances to account for the effects of heavy rainfall (Drainfall) and strong winds (Dwind). To overcome accessibility issues, a drone was used to map the TSF geometry and create a digital model. This model served as the basis for conducting a coupled stress-seepage, finite-element (FEM) analysis with a safety factor of 2.0 to assess geotechnical stability (Dcritical). The safe beach distance increments were determined using the PMP (probable maximum precipitation) and possible maximum wind speed. Based on this analysis, the optimal safe beach distance at the study site was identified as 202.2 m. Since the current beach distance (371 m) exceeds this value, the TSF was considered to be stable and satisfied the design safety factor of 2.0. However, this distance should be reassessed periodically to account for changes in the TSF geometry and other conditions. Furthermore, it applies only TSFs that are well-managed and feature a smooth, non-undulating beach surface with a consistent slope.

By P. E. Damon

An arsenal of isotopic techniques is avail-able that can date the full range of hydrothermal ore deposits. The following are prerequisites for ideal results: (1) Careful collection of samples that are related to the event in a field and process context; (2) Optical examination of the component selected for dating to be sure that it has not been altered; (3) Careful preparation of a pure component of the sample selected for dating; (4) Precise and accurate measurement; (5) Knowledgeable interpretation of the data with reference to decay systematics, properties of the component analyzed as well as the field context and thermochemical environment of the ore process.

Jan 1, 1992

By Richard A. Levins

The imposition of non-market regulations, such as the proposed SO2 standards for coal combustion, will typically lead to less efficient (thus more costly) production in a free enterprise system. For the coal industry these increased costs will occur in several ways, among which are mining less accessible low sulfur reserves and transporting low sulfur coal to distant markets. There are, of course, social benefits of reducing the S02 emissions from the use of high sulfur coal. The social benefits include decreased health risks, reduced damages to property, and certain unmeasurable benefits associated with the aesthetic appeal of clean air. Proponents of Federal S02 standards argue that the benefits gained from reduced emissions will exceed the costs borne by the coal industry and society in general in meeting the regulations. The purpose of this paper is to investigate the degree to which costs of meeting future energy demands from coal will change under different sulfur standards. No attempt is made to estimate the benefits of imposing regulations. Specifically, the impact of SO2 standards on the private costs of meeting regional coal demands, the competitive positions of the nation's major coal producing regions, the degree to which strip mining as opposed to underground mining will be feasible, the amount of coal being processed, and the amount of coal transported over major rail routes will be analyzed.

Jan 1, 1976

By William C. Cassun

The important role of pit slope design in the overall economics of open-pit mining ventures has long been recognized and well documented.1 2 Any economic analysis of a pit slope design must reflect the trade-off between the benefits and the increased risk of slope failure inherent in steeper slope angles. The conventional practice in pit slope design is based on the factor of safety analysis.' The approach uses average values to arrive at a deterministic solution to slope stability. Past analyses based on this approach generally have had several drawbacks: 1. The risk from slope failure could not be quantified. 2. Only relatively simple pit wall geometries were considered. 3. The analyses were performed solely for the benefits of steeper slopes, seldom discussing the potential costs of slope failures. 4. Analyses were seldom considered in a year-by-year mine planning context. Recognizing that average values do not reflect the uncertainty in geomechanical parameters, a probabilistic philosophy to slope design has evolved. 4,5 However, this approach had not been fully developed to include complex slope geometries and mine planning consideration. In order to develop an integrated, pit slope design procedure, a research project was initiated at the University of Arizona during 1973 in conjunction with the Canada Center for Mineral and Energy Teleology. This research resulted in the development of a probabilistic design procedure. The remainder of this paper gives an overview of the probabilistic design procedure and a discussion of the requirements for the benefit-cost analysis of a pit slope design. Finally, the results of a case study undertaken at an operating mine are given.

Jan 1, 1977

By H. Mischo, R. Ellmies

Uranium has been mined in Namibia since the 1970s. The worldwide increasing need for energy in the early 2000s has led to the development and opening of a second uranium mine in 2007 and has triggered an increased interest in uranium exploration, often referred to as “the Namibian Uranium Rush.” In all, four mining licenses have been granted by the Namibian Government, which currently has two mines in operation, a third undertaking trial mining and the fourth in project finance negotiations. In addition, highly intensive prospecting activities at additional deposits are at an advanced stage. The finalization of the strategic environmental impact assessment (SEA) on uranium mining in 2010, the first of its kind and scale in the world, has enabled the Namibian government to assess this uranium rush and its tremendous legal, socioeconomic and environmental impacts and to prepare for the different future scenarios conceivable when this article was written in 2011, including both a skyrocketing and a complete breakdown of demand scenario. The Fukushima disaster and plans of the Namibian government to significantly increase royalties and company taxes in 2011 have threatened the market situation, forcing investors to reevaluate Namibian uranium mining projects. However, with the tax and royalty increase initiative since withdrawn, most projects are back on track at this point in time.

Jan 1, 2012

By P. A. C. De Ruiter

The Lower Cretaceous salt deposits of the Gabon Basin and Congo Basin were said down on ton of an Burly Cretaceous Lato Jurassic, continental graben fill that represent!) the rifting phase of the Afro-American continent. The salt 13 characterized by high percentages of potash and magnesium salts and the scarcity of sulphates and carbonates. The salt probably originated from a brine that was already enriched in high-soluble salts before entering the Gabon Congo basins. Their low-solubility equivalents are found in the Cuanza Basin of Angola. Commercial mining of the potash salt is only possible in those onshore areas where it is essentially undisturbed, shallow and of the right chemical composition. These conditions are net in Congo where the Holle mine produces from rich sylvinite deposits.

Jan 1, 1978

By M. H. Rauschkolb, J. A. Cremeens

Geotechnical solutions were developed for closure of two historic, remote underground mines in the deserts of southern California. Closure criteria included access closure, minimal site impact, and optimum use of native materials. The closure designs and construction activities incorporated techniques for protecting sensitive biota, particularly bats and desert tortoise. The types of mine openings that were closed include adits, declines, shafts, daylighted stopes, and dugout dwellings. The desert locations permitted implementation of cost-effective closure techniques that relied upon the use of native materials. The strategies and techniques developed for these desert closures are adaptable to other climates.

Jan 1, 2002