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By J. J. Fallon

Las Vegas is a place of many distractions. It is difficult for one to apply himself to sophisticated technical matters in the midst of gambling, liquor, scantily clad young ladies and the top entertainment available in the United States. But, I know that the men and women of SME are made of stronger stuff and will not be tempted by these things.

Jan 1, 1989

By Thomas J. Kingston

A general overview of the taconite crushing process at Minntac is presented The process is controlled from a central control where the control room operator uses closed circuit TV, computer process control and alarms, graphic panels, and radio communication to roving attendants to run the Plant. This paper points out the operating controls and parameters as the plant operator sees and uses them.

Jan 1, 1980

By Edward M. Jacobs

In some ore grinding circuits it is desirable to make separations purely on size. The normal choice for this is vibrating screen equipment. Developments in screening process technology have led to improvements in the capacity and efficiency of vibrating screens, through the adoption "Thin Layer Wet Screening". This process can reduce recirculating loads and equipment requirements in the ore grinding circuit.

Jan 1, 1985

By L. W. Saperstein

P.J. Ehret By and large, I agree with many of the precepts discussed in the Saperstein paper. I believe there is much more that can be done on the local level to involve both government and planning in the mine permit review process. Admittedly, much can be done to improve discussion between the state regulatory authority, local authorities, and mine operators. However, I strongly disagree, as suggested in the paper's conclusion, that such a system, as outlined in Saperstein's paper, could result in a reduction of review time or a lowering in the cost of permitting. The implementation of such a system by its very nature would only add a new level of bureaucracy to an already cumbersome process. This system, in my opinion, would only add to the cost of permitting and the time necessary to obtain a permit. Admittedly, it would achieve the result of adding local influence into the permitting process, but at what off-setting cost? It has been my professional first-hand experience and observation in the permitting and lands unsuitable processes to note that under the present system, local governments that do feel they have a stake in local mines and actively ad¬vocate their position (not simply comment), have had significant input into the conduct of mining and reclamation plans in their areas. Mining companies that mine in these areas are aware of local interests and attitudes, and do consider them in their plans. Simply put, local governments that want to get involved and want to play significant roles can and do. Those that do not advocate a position or have no input to offer do not. Although the present system is not as direct in effect in regard to local control as Saperstein's, it does work. It does so without the red tape that would result from developing miniature regulatory authorities in every county in which mining occurs. Although local input is important, there are many more sections of the Surface Mining Control and Reclamation Act (SMCRA) than Sections 508(a)(8) and 522(a)(3)(A) that also are important. It appears Saperstein's paper may overindulge these sections. An additional specific comment is made in regard to the statement that while local areas benefit from mining (wages, salaries, and purchases), they also endure environmental deterioration caused by mining affects. It is believed that the whole purpose for which SMCRA and its resulting regulations were enacted and developed was so mining would not be permitted if significant environmental deterioration could occur. Therefore, it could be argued that this point under current law is moot. Reply by L.W. Saperstein P.J. Ehret writes in a reasoned and rational way and makes some good points. The arguments in favor of central control of the designation process reflect all of the benefits associated with central environmental control: consistency of enforcement, efficiency of operation, ease of communication among enforcing agency, etc. Nonetheless, the decision to mine or not to mine is a landuse decision which, in substance, is similar to the decision to build a shopping mall, a new highway, or a housing subdivision. Although, state and federal governments' interests in the protection of public welfare are real and are expressed properly in mining laws and mining enforcement agencies (OSM, Illinois Department of Mines and Minerals, etc). I continue to maintain that the permitting and designation processes should originate with local government, which is in keeping with the American tradition of delegation of the land-use decision to local or regional government.

Jan 4, 1984

By Lynton B. Manssen

Introduction Net Present Value (NPV) techniques are becoming widely used in industry as a standard analytical tool in making capital budgeting decisions. However, NPV techniques are often misused in "common practice." A comparison was made between the use of NPV techniques in common practice and an Adjusted Net Present Value (ANPV) approach to capital budgeting in the financial analysis of a mining project. The comparison was made by applying both methods to a hypothetical copper project. The intent of the analysis is to provide an example for practitioners to follow when financially analyzing mining (or other) projects. To maintain the thrust of the analysis, the project has been evaluated as a stand alone, total project. No consideration has been made of the division of cash flows accruing to various owners over the life of the project. This omission will not affect the comparative nature of the analysis. This discussion assumes that the reader is familiar with present value as a concept and as a tool in capital budgeting. Finance theory has embraced NPV analysis as the correct way to evaluate capital budgeting alternatives. Many articles have been written expounding the virtues of NPV over other capital budgeting methods, such as Internal Rate of Return (IRR), Payback, Accounting Rate of Return, and others. It is not the purpose of this article to review all of the literature in this area; suffice it to say that in academic circles NPV concepts are accepted as the norm. A survey by Schall, Sundem, and Geijsbeck (1978) indicates that major US companies are finally following in academia's footsteps. Fifty-six percent of the companies responding to the survey use NPV techniques in their capital budgeting process. Further, some 86% of the companies surveyed use discounted cash flow methods (NPV or IRR) for capital budgeting decisions. This compares with a survey by Klammer (1972) that showed 57% of companies using both techniques, a considerable increase in seven years. With the increasing use of NPV techniques in industry, there are certain uses in common practice that can give misleading results. Five common errors in NPV analysis of large projects are: • No distinction is made between real and nominal cashflows. • The discount rate(s) used in the NPV analysis is not formally adjusted for risk. • There is no distinction of possible differences in the riskiness of different project cash flows; i.e., revenue vs. depreciation. • There is no recognition of the cash benefits to the project from interest tax shields (interest payments on the project's debt that are tax deductible). • There is no clear recognition of subsidies to the project from concessionary debt financing. No Distinction Between Real and Nominal Cash Flows Often, expected cash flows for a project are stated as a mixture of real (in constant dollars) and nominal (in current dollars) cash flows. For example, expected revenue cash flows may be stated in real terms and depreciation may be stated in nominal terms. If cash flows are added together to give an after tax cash flow, and this single cash stream is discounted, care must be taken to ensure that cash flows are consistently stated. All cash flows should either be stated in nominal terms or in real terms. In addition, the discount rate used must be stated in the same terms as the cash flows being discounted. Real cash flows must be discounted using real discount rates and nominal cash flows using nominal discount rates. Discount Rate Not Adjusted Numerous methods for obtaining discount rates are used in common practice. Schall and others

Jan 6, 1983

By John W. Goth

This article, though not common feature material, should be of reader interest. Goth made this presentation as the keynote address at the 19th Annual Intermountain Minerals Conference in Vail, CO, in August. Introduction Working backward, what is an LDC? LDC stands for Less Developed Country. LDCs play a dynamic role in world supply and demand of basic materials. They occupy an equally important position in international marketing and finance. I will explain later some of my concerns with LDCs. First, I want to address an issue I think is of equal or even greater concern. Mining and High Technology Unfortunately, many people believe that America must make a decision now between being a smokestack-based economy or a high-technology-based economy. Some would have you believe that smokestack America is dead. Our only option is to turn to high technology, in a manner similar to countries such as Japan. Presumably, when we talk about high-technology industries we envision organizations that came into being within the last decade or so and incorporate microelectronics, biotechnology, and interconnected computers. The entire workforce is clad in lab coats and there are few employees in proportion to the work performed. High-technology industry is not labor-intensive work thanks to the efficient robots used. On the opposite side are smoke-stack industries, that we presume include the older, basic industries such as mining, agriculture, iron and steel manufacturing, ship-building, auto manufacturing, and nearly all forms of construction. These industries are judged to be labor intensive, requiring unsophisticated and untrained employees who succeed by the sweat of their brows rather than by advanced degrees in mathematics and physics. If these are indeed the presumptions about high technology versus smokestack industries, then I submit that those presumptions are a disaster. They are wrong and far from the truth. Smokestack industries, such as mining and the others mentioned, are indeed much older than some of the recently founded high-tech industries. But this does not mean that those smokestack industries are low-technology industries. On the contrary, American agricul¬ture is a very high-technology industry whose crop yields are the envy of the entire world. Mining uses virtually all of the advances available through modern technology. Far too many opinion leaders still envision mining as Humphrey Bogart and John Huston in the movie Treasure of the Sierra Madre. Yet there are many who hold the opinion that our basic industries are dead and that this country's future depends on specialized high-technology industries and services. That is tantamount to announcing we will continue to build space shuttle vehicles, but we no longer need launching pads and landing fields. The point is, we should not be wasting our time talking about "new" industries and "old" industries. We should devote our time and effort to industries that are effective and efficient in meeting our needs, in contrast to industries that are not effective and efficient in meeting our needs. Less Developed Countries That leads me to some of the problems I perceive with policies regarding the previously mentioned LDCs - Less Developed Countries. Far too many people do not realize that many of the smokestack industries being lauded in Less Developed Countries are being operated at a loss and to the detriment of worldwide industry. And the losses incurred

Jan 12, 1983

By S. D. Thompson, L. Adler

J.R. Sturgul Thompson and Adler (1988) present a new simulator for use in designing conveyor belt systems for underground mines. Their model uses a large Fortran program to do a Monte Carlo simulation. Their approach is similar to that done by other researchers, such as Stanford (1965) and Newhart (1977). All Fortran based simulation models use an imaginary clock that is advanced a time increment. At each advance of time increment the program has to determine what is to take place in the system. Since many things can take place at different places in the system, this approach requires that a large amount of logic is needed at each step of the program. This, then, necessitates a great amount of jumping between different portions of the program. In fact, the Fortran program, CMBCS, takes up to 15 to 20 minutes to run on the mainframe and several hours for the PC. Such execution times are typical of Fortran based simulation studies. There have been other examples of Fortran based simulation studies in mining. Cross and Williamson (1969) presented a model of a working open-pit copper mine. Fosinato (1982) presented a model of the bucketwheel excavators for the large open-pit mines in Southern Victoria in Australia. These excavators discharge into a complex conveyor system, which can be thought of as being similar, but more complicated than the one modeled by CMBCS. All previous simulation studies using Fortran as the source code have several things in common: they all are very lengthy, often being of the order of 10,000 lines of code and take a great deal of CPU time to execute. The program of Fosinato takes more than 4.5 hours to run on a large mainframe. Also not mentioned by Thompson and Adler is the actual time it took to write the Fortran code. This, too, can be considerable, as Fosinato's program took several man years to write and de-bug. In order to change it, as the parameters change or as the mine increases, further large amount of time is needed. An alternate to such Fortran based programs is provided by using a special computer language known as General Purpose Simulation System (GPSS). This language is designed to solve a wide variety of discrete event simulation problems and appears to be particularly suited for mining situations as shown by Sturgul and Yi (1987). Although GPSS was introduced as far back as 1961, it has not been used in mining to any great extent. However, the original form was quite crude and inefficient compared to modern versions. Perhaps with the increasing popularity and availability of these recent versions, this will change. Two such versions are GPSS/H for the mainframe and GPSS/PC for the personal computer. GPSS/H allows for interactive usage, such as allowing input data to be entered via a menu. GPSS/PC has excellent graphical capabilities and one can actually view the simulation in progress. In addition, one can halt the simulation and change values of various parameters. If a particular portion of the simulation is in progress via a concept known as "microwindows." These new versions have greatly increased the potential for using the language for mining situations. Mining applications of GPSS have been given by Sturgul and Yi (1987), Sturgul and Harrison (1987), Sturgul (1987), and Sturgul and Singhal (1988). Schriber (1987) presents a summary of the recent advances in GPSS.

Jan 12, 1988

By H. G. Fleshman

The economics of western sodium bentonite (also known as Wyoming Bentonite) is covered from exploration to delivery to the final user. Included are costs of exploration, evaluation of ore bodies, mine permitting, stripping, loading, hauling through stockpiling, blending, processing and shipping. Since western bentonite is one of the industrial minerals marketed throughout the world, the various markets and freight costs are included.

Jan 1, 1984

By Richard H. Olson

The following discussion will deal with the domestic talc industry only, inasmuch as the writer has had no experience in this field outside of the U. S. This is strictly a geological-mining approach; no attempt is made to assess in depth the effects which milling technology and marketing capability might have in determining the potential of any given talc deposit.

Jan 1, 1970

By J. M. Keane

Critical to successful dump and heap leaching for copper is an adequate testing program for evaluation of the applicable parameters. This paper deals with testing methods to establish best conditions for dump and heap leaching of copper so that commercial operations can proceed on a rational basis. Discussion is also offered of ore occurrences suitable for dump and heap leaching.

Jan 1, 1985

Electronic detonators have been in commercial use for a decade, with an excellent safety record. This paper lists known incidents involving electronic detonators. Typical standards required by regulatory bodies for static electricity and electromagnetic fields are reviewed. The performance of some detonators is compared to these standards; in general the minimum standards are easily exceeded. The general resistance of electronic detonators to extraneous electrical energy that can be derived from the body of test results is compared to danger levels for exposure of humans to these energies; it is shown that electronic detonators can safely tolerate higher electrical energies than people can. This comparison includes comparable data for electric detonators, which are shown to be more vulnerable to extraneous electrical energy than people are. Electronic detonators also bring significant safety benefits in blasting due to their testability, two-way communications, reliability, programmability and precision. The links between these attributes and enhanced safety are discussed with examples from actual blasting. Although electronic detonators are usually more vulnerable to extraneous electricity than non-electric initiation systems, the paper shows that the net safety benefit in handling and blasting is in favor of electronic detonators, which are the safest initiation system that has ever been offered to the mining industry.

Jan 1, 2010

By R. Maurice King

In the operation of today's large scale ore-processing mills, it is extremely important to have some way of making an objective evalu¬ation of the performance of the available flotation reagents. Attempts to do this may often result in inconclusive findings since the magnitude of the difference in the mill results for any two reagents is apt to be quite small compared to the variability introduced by the process and 'the analytical procedures used to measure them. In cases where two reagents give vastly; different mill results, evaluation becomes a simple matter and as such deserves no further attention here. A question of primary concern, however, is how a mill can go about evaluating the performance of two reagents which may, for example, give a difference of only 0.001% copper in the-tailings or of 0.2% in copper recovery. The casual observer may feel that such small differences may be of little importance, but in a mill-whose daily tonnage is between 30 and 40 thousand, these differences could mean a substantial savings. Before the presentation of an actual example of a reagent testing scheme designed for just this-purpose, perhaps a few minutes should be devoted to a review of some statistical methodology to be used later in the discussion.

Jan 1, 1964

By George F. McKeregahan

Phosphate production of the Central Florida Phosphate District has been predominantly from the unique and lucrative Bone Valley Formation, with local and minor amounts coming from the underlying Hawthorn Formation. As the Bone Valley is depleted, replacement production will move progressively into areas of total Hawthorn Production. Significant changes in the characteristics and make-up of the deposit dictate required modifications in mining and beneficiation. Failure to tailor technology to fit the deposits of the future will result in vast "reserve" losses. In the Southern Extension of the Central District - two distinct "ore types" exist. These are presently referred to as the upper (high grade) zone and the lower (low grade) zone. The upper zone is somewhat similar to the Bone Valley Formation and will respond favorably to present beneficiacion practices. The lower zone is strikingly different and its response to conventional beneficiation is not acceptable. The major differences are in grain size distribution and mineralogical make-up of these grains. The Hawthorn differs from the Bone Valley by exhibiting lower grades, lower tonnage yield per acre foot, lower pebble percent of product, higher mining ratios, higher slimes (-150 mesh) content and deeper mining depths. Physical characteristic changes include more frequent occurrences of competent bands or lenses of "limerock" which are submarginal in value.

Jan 1, 1983

By C. O. Brawner

INTRODUCTION My first major involvement on a rock mine slope stability project was in 1966 after I had become a principal of Golder Brawner & Associates in Vancouver, Canada. I received a request from Kennecott to evaluate two serious rock slope failures adjacent to the concentrator on their British Columbia molybdenum property near Alice Arm, BC, which was under construction. A rock slope up to 200 ft* high had been excavated at a design angle of 700. The inspection indicated that several large blocks of about 1000 cu yd each had failed on steeply inclined joint surfaces. Stability was reduced by extensive seepage caused by heavy rainfall. In addition, considerable overbreak had occurred, indicating excessive blasting had been used to excavate the slope. A program was developed to rock bolt potentially unstable blocks that could slide on dipping discontinuities. Some rock was scaled back to the inclined joints, and drain holes were drilled to reduce water pressures. The project was completed successfully and within reasonable economics. As a result of this success, enquiries were received regarding other mining projects. This indicated the potential demand for rock slope engineering. As a result, I took one month off to meet and discuss rock mechanics and slope stability with various people internationally. These included D. Coates in Canada, E. Hoek in England, K. John and L. Mueller in Germany, M. Rocha in Portugal, and the US Bureau of Mines in Denver, CO. Early misconceptions Based on involvement in projects during the next few years, it was concluded that there were a considerable number of misconceptions that existed among some geologists and mining engineers dealing with surface rock mechanics. Some of these included: • Water is a lubricant. This is incorrect. Water reduces the shear strength along discontinuities due to buoyancy, which reduces frictional strength. It also reduces the cohesion of clayey-type rocks. • The optimum pit slope angle in rock is 45°. The optimum slope angle for safety and economics is variable and is influenced particularly by structural geology, water pressures, mine blasting practices, and the depth and degree of weathering. • The flattest angle for slope stability is dictated by the angle of repose of broken rock, about 370. Where clayey-type rocks or clayey infill in discontinuities exists, failure can occur at much flatter angles, requiring flatter slopes or artificial stabilization. • Uniaxial and triaxial tests provide the necessary shear strength parameters to design rock slopes. Most failures in rock slopes are controlled by directional discontinuities. Therefore, the direct shear test is the correct test to evaluate strength parameters for most problems.

Jan 1, 1987

By Boghani. A. B.

A computer program has been developed to simulate evacuation of a mine in various configurations. The simulation input variables include characteristics of the mine, expressed, in the form of a network of passages, properties of hoists and hoisting strategies, initial miner positions, ventilation and compressed air velocities, stench warning system and self rescuer capabilities. The simulation can be carried out for cases in which there is no fire, i. e. , fire drill simulation, or for cases in which there is a fire at any arbitrary location. The fire is assumed to generate gases which impede movement of miners in the gaseous region. However, the thermal effects of the fire are not considered. The simulation output include the evacuation time for each miner, movement of the hoists, propagation of smoke through the mine passages and smoke exposure of the miners. Several illustrative simulations have been carried out to verify validity of the program and to demonstrate its capabilities. The computer program has been able to predict evacuation time, within 5 percent, for an actual fire drill. It is believed that this program can be used to evaluate evacuation performance of a mine, identify problem areas and demonstrate improvements due to the recommended corrective actions.

Jan 1, 1977

For processing plant design it is essential to develop a consistent material and (usually) energy balance as a basis for equipment sizing. This paper discusses techniques for consistent material balance generation, from hand calculation, through spreadsheets to specialised computer programs and general purpose simulations. The appropriate matching of techniques to problem complexity is considered, as are some possible trends for the future.

Jan 1, 1991

By Cayo Soto

Mining activity is important for the development of humanity. This development must be understood from the Academy where it allows showing alternatives for the industry performance. Likewise, these mining companies need to improve their results. Historically, a few years ago the application of the ESG (Environmental, Social and Governance) criterion was verified, which is positioned as a factor/regulator in the design of the performance of industries in general. ESG as an integral part of the concept of sustainability serves as a tool to conceive mining without conflicts and with a reputation based on trust in the interrelation of the university, industry and society. Therefore, the academy must strive for new knowledge in a way that allows it to continue in the virtuous circle of constantly feeding it. In this context, the best mining practices are implemented in constant questioning of their activities. The scientific essence of the industry supported by the academy developed in an operational dynamic is addressed. Finally, the objective of this research work is to interrelate 3 variables: ESG, Academia, and the Mining Industry, where the transition of knowledge and the role of each variable in relation to each one can be understood. This allows for an additional understanding of mining in the future with new mental attention.

Feb 1, 2025

By J. D. Miller, C. L. Lin

A PC, image-based, on-line instrument for measuring coarse particle size on a conveyor belt is under development. The hardware and software required to implement such a system are discussed, including the interface for the special image-acquisition hardware. The system concept is given with examples to illustrate the step-by-step procedure for the implementation of image-processing algorithms.

Jan 1, 1994

By Walter N. Campbell

The Simon Silver Mine is located near Mina, Nevada, approximately 50 miles northwest of Tonopah and 40 miles east of Hawthorne. It is an old property which was last worked in 1932 and closed operations due to problems arising from low metal prices. Federal Resources Corp. acquired the property in 1963 and undertook a completely new development program since the old surface plant and underground workings were beyond feasible repair. The deposit of silver, lead, zinc and copper is predominantly replacement of limestone. In the summer of 1964, a new surface plant was constructed and on December 2, 1964, sinking of a three compartment vertical shaft started and was completed to a depth of 1088 feet in April of 1965. Following the sinking program an 850 foot crosscut was driven to intersect the mineral zone on the 1000 level after which drifting, crosscutting and raising totaling some additional 4280 feet has been completed along with considerable diamond drilling and long holing into the walls. To date, two ore bodies have been encountered and test stoping operations are underway together with development of the 800 level for servicing, ventilation and access. The present development of ore is directed towards substantiating sufficient reserves to warrant the construction of a flotation mill.

Jan 1, 1967

By III Boxley

Most of us realize that our nation's roadways are under ever-increasing stresses, from higher traffic counts to increased tire pressures and their resulting loads. At a time when the interstate system as originally envisioned is completed, and the National Highway System is being drawn to replace it, it is appropriate that we examine design and construction methods for the next century. The stone industry shares a common desire to produce high quality, cost-effective roadways that perform over time. The superior sub-grade and road base structure provides for the superior roadway. Since I am neither an engineer nor a contractor, I will not attempt to suggest design or construction methods. What I can do is share my company's experience in supplying road base materials by using a historical perspective in Virginia and some trends in the market that we have observed. Road building and related non-building construction are still far and away our largest markets as an industry. If we can help to improve the end product of our biggest customers, we add value to our own product. Indeed, in a time of budget constraints and competing demands for government dollars, we must show value over the life of a pavement structure to ensure their long-term funding.

Jan 1, 1996