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By B. J. Swenty, J. L. Hubbard, R. L. Peyton

Based on the results of the National Program of Inspection of Nonfederal Dams conducted by the US Army Corps of Engineers during 1977-1981, Missouri was found to have the highest number of "unsafe" dams in the nation. Many of the dams classified as unsafe in Missouri were tailings dams.

Jan 1, 1987

By J. H. LaVerne Palmer, W. (Bill) C. Cox, Lorant B. Geller

An erector transporter (ET) has been designed and built to lift, carry and erect heavy machinery components, in particular the components of a 7.6 m diameter tunnel boring machine (TBM), within the access tunnels of a submarine coal mine in Eastern Canada. The ET is capable of manoeuvring within a 7.6 m tunnel while precisely positioning components as large as 6 m in diameter and weighing up to 27 tonnes each. The unit can negotiate 20% grades while carrying loads of 30 tonnes. The major design features, verification tests and performance trial results are presented. The versatility of the ET is such that many other applications are possible.

Jan 1, 1985

By David Corkum, David Hatem

Subsurface construction projects are risky ventures and the decision to deliver a project using the Design-Build model does not eliminate those risks. Differing site conditions, inadequate design, and delays will continue to plague some projects. The Design-Build procurement model, however, presents a broad opportunity to allocate those risks much differently than in the familiar Design-Bid-Build model. Starting with a philosophical approach to risk and reward, this paper discusses the continuum of possible risk allocation strategies. It concludes with a proposed optimum strategy in terms of the project’s overall economic efficiency, and points to the dispositive contractual provisions that serve to contour the risks.

Jan 1, 2003

By Fang-tu Wei

The purpose of developing this system is to monitor the operating status of the fully mechanized mining system in order to raise it's reliability. The completely mechanized coal mining system is a complex dynamic system, involving many sub-systems. It is the key of the mining process as well as a connected system composed of each working procedure. Any hitch in breaking, loading or transporting will interrupt the mining process. The analyses of the operating data has proved that the reasons causing the interruption of the extracting processes mainly come from the inner of coal face. Hence, after the installation of the MINOS system in England, the delays of belt conveyor sub-system were reduced. But the production increment was not as much as expected.

Jan 1, 1986

By G. G. Marino, Z. R. Widup

Marino Engineering Associates, Inc. (MEA) was asked to determine the effects of mining beneath a proposed roadway structure. In order to determine the subsidence potential and the magnitude of the mine stabilization costs it is important to know whether underground mining is present, and if so, to what a real extent. The site investigated had the potential to have mining in three different coal seams. To determine where mining was present MEAÕs borehole radar system was used. In summary, the borehole radar subsurface investigation validated that the available mine map in the most shallow coal seam was fairly accurate despite its age (1888), found no mining in the underlying coal seam and detected an area of unknown mining at a depth of about 300 ft in the lowest coal seam which was verified by subsequent drilling.

Jan 1, 2004

By Olli Järvinen

The precious metal refinery process is divided into the five process stages: 1 .copper/nickel leaching in autoclave 2. selenium roasting furnace 3. doré metal smelting furnace 4. silver electrolysis 5. gold recovery system. The process has been developed during the years in Outokumpu Harjavalta Metals, which treats about 600000 kg /year copper anode slime. The slime treatment process route in Outokumpu Pori plant has been developed from year 1941. During this period the process has been improved radically. The major changes has been the atmosphere leaching into the autoclave leaching, the sulfuric acid roasting furnace was changed into sulfuric dioxide / oxygen roasting. The old doré smelting furnace has changed into the TROF converter and the gold electrolysis / aqua regia process has changed into the quick hydrochloric acid leaching process. The current production in Pori plant is 30000 kg of silver, 1000 kg gold, 30000 kg of selenium and some hundred kg of platinum- palladium concentrate.

Jan 1, 1995

By D. D. Lei, H. Sevim

In a recently developed, long-term open pit production planning model, the optimal plan is found by exhaustively searching through nested pits of maximum metal contents. A more efficient, dynamic programming (DP) based search algorithm now replaces the exhaustive search algorithm that requires prohibitively long execution time in real life cases. The logic and formulation of the newly developed search algorithm are illustrated through a small hypothetical case. An actual gold deposit is treated to demonstrate that the algorithm does indeed find the optimal production plan among all possible plans. A comparison, in terms of computational savings between the two algorithms, is also given.

Jan 1, 1995

By D. B. Stephens

Assessing the occurrence of natural ground-water recharge at mine and mill waste disposal sites may be crucial to addressing regulatory agency concerns regarding the potential impact of waste seepage on ground-water resources. Recharge has been shown to occur even in semi-arid areas where annual lake evaporation exceeds precipitation. Permanent storage of waste seepage in the unsaturated zone is not to be expected if recharge occurs under natural conditions. Establishing the direction and rate of fluid movement in the vadose zone by field measurements is an important element that should be included in the site selection process.

Jan 1, 1987

Significant economic deposits (> 4,000 ha) of heavy mineral sands (ilmenite, rutile and zircon) were discovered in the Atlantic Coastal Plain of Virginia and North Carolina in 1989. The majority of these lands support highly productive row crop agriculture, and the development of restoration protocols that would return these lands to agricultural use was deemed to be critical to the long-term sustainability of mining operations. Virginia Tech worked closely with all stakeholders to develop appropriate restoration protocols and to coordinate their implementation. Full-scale mining operations at the Old Hickory Project in Virginia were initiated in 1997 by Iluka Resources Inc., and restoration protocols have continued to evolve in response to a variety of economic, technical, and social issues. Return of these lands to agricultural row-crop production has been complicated by lateral variability in soil physical conditions in the reclaimed pits and limited topsoil return. Approximately 150 ha of land are in various phases of reclamation, and approximately 25 ha have been released back to landowners to date. Currently, the reclaimed pits are returned to pasture vegetation, but return to more intensive agricultural production practices may be possible as soil reconstruction procedures are improved over time.

Jan 1, 2003

By M. Kumral

The in-situ mineral characteristics of a deposit are simulated by sequential co-simulation and averaging the simulated characteristics within specified block volumes creates a three-dimensional block model. This model is then submitted to optimal open pit and production scheduling algorithms. As the market values of industrial minerals depend on the satisfaction of predetermined blending criteria rather than metal content, a Linear Programming (LP) scheme has been used to identify all blocks that can be included in the blend without violating the grade requirements. The Lerchs-Grosmann algorithm using the blocks identified by the LP program determines optimal pit limits. All blocks that lie outside the optimal pit are removed from the system and the blocks within the optimal pit are submitted to the production-scheduling algorithm. Production scheduling optimisation is done in two stages: Lagrangean parameterisation, resulting in an initial sub-optimal solution, and multi-objective simulated annealing (MOSA) improving the sub-optimal schedule further.

Jan 1, 2002

By R. M. Imhof, M. J. G. Battersby, J. V. Brown

There is a plethora of former industrial sites where coal mining operations have left large slurry impoundments. These contain raw washed fines, which have previously been too expensive to process to requisite grades for commercial use. New technology has been developed for fine material processing, namely the Imhoflot pneumatic flotation G-Cell. This froth flotation technique is a highly efficient means of concentrating coal and is particularly appropriate to the nature of materials encountered in tailings ponds. The high volumetric throughput resulting from the vastly reduced residence time in the cell allows for drastically reduced equipment sizes when compared to conventional flotation cells. This means the process, when combined with innovative pre treatment and filtration equipment can be developed as a mobile plant concept. This is seen as a minimum requirement when re-treating and rehabilitating fine coal ponds.

Jan 1, 2003

By Eugene E. Brucker

In recent years, there has been increased interest in construction problems presented by karst topography. Twenty-five years ago, karst areas were by-passed for development. Today, the high cost of land and population pressures are requiring utilization of karst areas. Areas exhibiting karst features can be satisfactorily developed so that construction can proceed in a normal manner; or the areas may be left undeveloped and the underground drainage system abused by improper use causing or contributing to structural collapse, excessive erosion, and a grave threat to the stability of land development and the environment. The term "karst" is a comprehensive term applied to areas underlain by soluble rock that possess a topography formed chiefly by the dissolving of rock and the diversion of surface waters to underground routes. There are four features which contribute to the maximum development of karst. 1. A soluble rock, preferably limestone, must be present at or near the surface of the ground. Occasionally, dolomite will suffice.

Jan 1, 1970

By J. Astier

The idea of using only one strand for both sintering and cooling of the sinter is not new. In 1952, in the U.S.A. a sintering plant was built at Benson Mine (Star Lake, N.Y.), including : - 68 m2 or 735 sqft (8 wind boxes) for sintering, - 22 m2 or 237 sqft (3 wind boxes) for cooling. In the USSR, a large number of machines have been built allowing for cooling of the sinter on the strand, especially the 4 m (about 13 ft) machines, with : 252 m2 sintering grate area 60 m2 cooling grate area 312 m2 total grate area. However, such ventures did not prove very successful, and the IRSID embarked many years ago on a research program to discover : - what are the problems associated with cooling on a sintering strand ; - what are the possible solutions for industrial plants.

Jan 1, 1974

By L. Andrews, G. Smits, M. D. Adams, E. A. Viljoen

A new approach has been developed that is capable of ascertaining the ore component that is responsible for the preg­robbing of pregnant pulps. Many gold mines are currently treating ores containing a component that is detrimental to the recovery of gold, in that they "preg-rob" the pregnant pulp by adsorption of some of the dissolved gold. The identity of the preg-robbing component in this type of ore has been the subject of considerable debate over a lengthy period, th various suggestions including amorphous carbon, chlonte, chalcopyrite and layered silicates, such as the phyllosilicate minerals pyrophyllite, kaolinite, phlogopite and illite. A means is now available to identify and characterize the preg-robber in gold ores. This new approach consists of contacting the ore with a synthetic aurocyanide solution, identifying the mineral grains by optical microscopy and analysing each grain individually using high-sensitivity electron microprobe analysis. The approach is exemplified in this initial study by identifying the preg-robbing component in an active sample of gold-bearing shale to be an amorphous carbonaceous phase consisting of discrete particles of about 5 µm diameter interspersed with shale particles and agglomerated into grains of up to 100 µm diameter. Microanalysis of these grains as well as other mineral particles revealed that the gold content of some of the carbonaceous grains was close to 7000 g,lt, with no gold being detected in any of the other mineral phases that were found to be present (e.g. quartz, chlorite, muscovite, pyrophyllite, etc). Bulk analysis of the sample for carbon and gold confirmed that gold loadings of around 7000 g,/t would be expected if all of the gold were adsorbed onto the carbonaceous component. The carbonaceous constituent is probably also responsible for the anomalously high surface area measured for the material. It probably acts in a similar fashion to activated carbon, and the correct choice of organic blinding agent will decrease the extent of preg-robbing by lowering the activity of the material for gold, without causing any downstream problems such as fouling of the activated carbon used for gold recovery

Jan 1, 1993

By B. Nyman

A lot of work is in progress to improve copper recovery by leaching-solvent extraction-electrowinning (L-SX-EW). At Outokumpu the focus of attention is on SX equipment development as a result of which a new mixing-settling technology, the Vertical Smooth Flow (VSF) has been introduced. Using helical stirrers in the VSF mixers a more gentle and uniform contacting can be obtained than in the mixing compartments of the low-profile design. The benefits of Outokumpu's new approach are an essential decrease in organic losses and in aqueous in organic entrainments. Separate pumping using a smoothly pre-contacting "Dispersion Overflow Pump" (DOP) is a key feature of the VSF design. The scale-up of this pump as well as the VSF mixers are shown to follow simple mathematical relationships which also have been confirmed by full scale experiments.

Jan 1, 1995

By Roderick G. Eggert, John E. Tilton

During much of the 1970s and 1980s, world metal consumption grew more slowly than during the 19505 and 1960s. The slowdown contributed to surplus capacity and low real prices because actual consumption was consistently less than expected as new mining and mineral processing capacity came on stream. Over the last year or so, however, world metal consumption has picked up noticeably, raising the question, Has metal demand returned to the long-run growth rates more typical of the 1950s and 1960s than of the 1970s and 1980s? This paper examines this possibility and, more generally, assesses the factors that will shape demand for the major metals over the longer term. TRENDS IN METAL CONSUMPTION The extent to which metal consumption has recaptured the brisk growth rates typical of the 1950s, 1960s, and early 1970s is shown in Figure 1. This figure traces the consumption of crude steel, primary aluminum, refined copper, refined lead, and refined zinc between 1960 and 1987 for the western world, consisting of the OECD countries (including the United States), and the developing countries. Consumption increased in 1987 for all five metals, and preliminary data for the first six months of 1988 suggest even more substantial increases, at least for the United States (U.S. Bureau of Mines, 1988). However, Figure 1 also shows that the recent increases in consumption are not untypical of similar surges during earlier periods of economic expansion and thus may reflect only cyclical or temporary factors. In short, the available data are unable to provide a clear indication of whether recent increases in metal consumption reflect the beginning of a new era of faster growth or simply a cyclical and temporary upturn associated with the expansionary phase of the business cycle. Consequently, to pursue this issue, we are forced to examine the underlying forces that will shape metal demand trends over the next decade. The approach we have taken involves two steps. The first examines the prospects for overall economic growth. The expectation is, the faster the economy expands, the faster the production of metal-containing goods grows.2

Jan 1, 1989

By Edward DeLilla

Formalized technical audits for mining machinery during manufacturing are a fairly new concept to the North American mining industry. Although used extensively elsewhere, especially in Australia, the concept of independent auditing of machinery design and manufacturing has been slow to gain acceptance in the United States and Canada. Simply stated, a technical audit is an independent, third-party review of all or specific portions of machinery design, manufacturing and assembly to verify compliance with purchase specifications and suitability of the machinery for the specified application. If specified correctly, the useful life of different kinds of structural and mechanical components can be extended beyond normally accepted usage. There is no reason why, if properly designed and built for the application, major structural components on mining machinery cannot be made to last for 20 years before being rebuilt. Also, gearing can be made to routinely last for 15 years.

Jan 1, 1995

By Arpad E. Torma

The introduction of biotechnological principles in hydrometallurgy has created new opportunities and challenges for the industry of mineral processing. During the 1950's and 608s, the mining wastes and unused complex mineral resources have been successfully treated in bacterial assisted heap and dump leaching processes, especially for the production of copper and uranium. The economic viability of bio- leaching technology lead to its world-wide acceptance by the mining industries. During the 1970's this technology grew into a more structured discipline which is called "biohydrometallurgy". Currently, bioleaching techniques are ready to be used, in addition to copper and uranium, for the extraction of cobalt, nickel, zinc, gold and silver from diverse mineral resources and for the desulfurization of certain coals. However, in a foreseeable future the biohydrometallurgical processes may be applied also for the treatment of high- grade ores and mineral concentrates using native and/or genetically engineered microorganisms.

Jan 1, 1989

By Kerry M. Masson

Perhaps the hottest item on the agendas of most state legislators this year is the state budget. The main question: Where will all the dollars come from to finance health care programs, state jobs, unemployment compensation programs, and on and on? This is especially so since people are out of work, business bankruptcies are up, sales are down, and incoming revenues from some sources have decreased or dried up. A sure bet is that state taxes will be increased in some form or another. The mining industry could face increased income taxes, property taxes, severance taxes, or even a host of new taxes (if the state does not already have them) like a gross receipts tax, investment tax, or tax on revenues made outside state borders. That's bad news for an already depressed industry, even though increased taxes may be the least of the industry's worries in the current economic climate. While reopening existing mines and developing most new mineral projects depends primarily on higher commodity prices, new taxes still could pose long term concerns for mine project development. Just how mineral tax law impacts a project is not easy to figure. It involves a complex set of calculations based on interpretations of numerous federal, state, and local tax laws that change almost annually. At best, projections of tax effects for the life of a mine are educated guesses. At the same time, projections are necessary to evaluate the economic feasibility of a mineral project. At a recent Technology Transfer Seminar, the US Bureau of Mines introduced a computer software program designed to evaluate the feasibility of a mineral project and to determine the tax effects on the project's discounted cash flow rate of return (DCFROR). The program, called MINSIM, began in 1967 as a 200-statement FORTRAN II program for evaluating a hypothetical large-scale open-pit gold mine. This single-commodity oriented program employed discrete simulation techniques and a continuous DCFROR was used to measure the effect of changes in revenues and costs. Over the past 15 years, MINSIM has developed into a program 70 to 100 times larger than the original. Basically, it will analyze costs and parameters specific to an identified deposit, then determine the DCFROR. Or by using a specified DCFROR, it will determine the primary commodity price required to attain that specified rate of return. MINSIM, which is explained in detail in this article, is available from the Division of Minerals Availability, USBM free of charge. Written in FORTRAN IV, it comes on punch cards or magnetic tape and is compatible with most major computer systems. The MINSIM Program The main objective of any freeenterprise mining venture is to make a profit. To determine profitability of a given project, alternate methods of operating and financing must be evaluated. That is the purpose of MINSIM. While there are a number of methods of evaluating the economic profitability of a mining project, MINSIM uses the Discounted Cash Flow Rate of Return (DCFROR) method as its major criterion because DCFROR considers the time value of money and gives the truest measure of profitability. One disadvantage is that the calculations are deposit oriented. In other words, MINSIM analyzes only those costs and parameters specific to the deposit. It cannot be used to evaluate the overall corporate picture. The program is designed to simultaneously handle five different commodities and a leach operation for any type of mining project. For example, analysis of a coal project would include only one commodity-coal at the mine mouth. Analysis of a copper operation might include numerous commodities-from the raw material to the refined product. Input MINSIM considers capital investment-recoverable exploration, acquisition, and development costs; depreciable capital investments such as mine plant and equipment, mill plant and equipment, and infrastructure costs; all general and commodity specific operating costs; and the cost of alternate financing methods. The program has the capacity to incorporate different types of depletion allowances, numerous commodity-dependent severance taxes, variations of property taxes, and many methods for calculating state or provincial taxes. There are even many different ways to calculate federal and national taxes. The capacity to handle tax variations is generated from an internal subroutine in the program called the "open file." The user can reconstruct, customize, or evaluate any kind of tax desired. Outputs Given this kind of capacity for numerous input parameters, MINSIM is capable of the follow¬ing major outputs:

Jan 3, 1983

By Lowell T. Harmison

I appreciate very much the invitation to speak with you and the opportunity of bringing you messages from both the Secretary of the Department of Health and Human Services and the Assistant Secretary for Health/Acting Surgeon General of the U.S. Public Health Service. I would like to take this opportunity to congratulate you (the organizers of this Conference) on identifying the critical issues in the field and assembling such a broad array of experts to address them. I would like to present a brief view of the emerging framework for health that puts into perspective some of the aspirations of the Administration and to highlight several points with regard to prevention and occupational health. The goals are: 1. To improve the overall health status of our people. (This has been and will remain the National policy regarding health.); 2. To engage the Nation in the important effort of enhancing public health. (This is not reserved exclusively for the activity of the Federal Government or for State Governments. Public health has to be a cooperative effort that brings together all of the people engaged in the process of serving the people.); and 3. To pledge that health care will not be priced out of anyone's reach because of inflation. (It is clear that there are major tasks of bringing about economic recovery in our country. One aspect of this effort is to guard against the cost of health care not being allowed to rise beyond the reach of persons who need that care.) "How will these goals be achieved and what must change in the delivery of health and medical care in our society?" There are a number of real issues as well as perceptions that adversely affect the attainment of these goals: First, The cost of medical care is soaring and the public, industry unions and other elements of our society are becoming concerned. (They recognize the problem and are demanding a solution.); Second, There is a growing concern about the priorities that have been set. (For example, the evidence that preventive interventions are the most effective approach is overwhelming, yet medicine has not yet given that a high priority.); and Third, There is the perception that physicians do too much to too many people at too great a cost and that too much and too costly technologies are used. In view of the perceptions, we all must accept some changes and the challenges that needed changes will bring. A month before the new budget went to Congress, President Reagan went on nationwide television and told the American people that, "It is time to recognize that we have come to a turning point and we are threatened with an economic calamity of tremendous proportion and the [old business as usual treatment can't save us. Together we must chart a new course]." Now eight months down the road from this and a long Spring and Summer of discussion both within the Executive Branch and in the Congress, many plans and programs and concepts have emerged. The new course has been charted and the turning point has been made. Business as usual has been put aside and the Administration's leadership has been stretched and tested in putting forth a better approach with the reality that money is tight and that old habits of delivering care are difficult to change. The Congress has now given us a look at a new health budget that takes into account some of the harsh economic realities and that does make allowances for the persistence of familiar behavior. Against this background, it is now possible to begin addressing ways to provide health services to people at a price the Nation can afford to pay. There are without question difficult decisions involved but the Administration is committed to supporting and improving health care in America. It has been the President's contention that one of the principal causes of the inflationary spiral in the country was the steady and indefensible growth of the Federal budget. The problem stems from the fact that we have been living well, but beyond our means for nearly 30 years. Now we are discovering that there is a bottom to the barrel after all. It is possible for our society to run out of things like energy (oil), water or money. The health bills must be paid -- by Government, by insurance, by parents or by someone. Each year with a bigger shopping list and more money to spend the Federal Government went into the marketplace to buy. This action altered the

Jan 1, 1981