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By J. C. Motz

With ore grades continually decreasing and finer mill feed requirements, it becomes increasingly important to have the capability to handle the larger tonnages economically. With the 10 ft. Standard capable of reducing 1,633 metric tons per hour (1,800 short tons per hour) to 80 percent passing 50 MM (2 inches) and the 10 ft. Short Head following to produce a mill feed of all minus 12 MM (1/2 inch) at a rate of 608 metric tons per hour (670 short tons per hour), we feel significant savings will be realized in installation and operating costs. The largest concentration of cost in the secondary and tertiary crushing stations is the building itself that houses the process equipment. An example of the savings to be attained can be seen from an examination of a 40,820 metric ton (45,000 short ton) per day crushing plant. A total of nine 7 ft. Symons Cone crushers is used to generate 12 MM (1/2 inch) ball mill feed. The average center distance between units is 6.1 M (20 feet) and allowing a 6.1 M (20 feet) nominal distance from the centerline to the wails, the building becomes 61 M (200 feet) long. For this production rate, four 10 ft. Symons Cone crushers would be required. With the 10 ft. crushing plant requiring a center distance spacing of 7.6 M (25 feet), the building length totals approximately 38 M (125 feet). Construction costs vary depending on location, but a reduction in building length from 61 M (200 feet) to 38 M (125 feet) will result in estimated savings of between $2,500,000 and S4,000,000. While the 10 ft. Symons Cone has been involved in a number of feasibility studies for some time, the Process Machinery Division of Rexnord commenced detail design work on the 10 ft. Cone crusher in 1972. For comparison purposes, the 10 ft. and 7 ft. capacities are given in Table 1.

Jan 1, 1978

Those who have had an occasion to apply geostatistics to the estimation of ore reserves are familiar with the conventional approaches of estimating average grade of quality values for arrays of regular grid squares or blocks. Further, the technology to perform geostatistical analysis and prediction for irregular two-dimensional areas has been available in a practical, readily useable form for some time. However, the generalization of this technology into three dimensions has been hampered by lack of a suitable geometrical characterization for realistic, three dimensional shapes and volumes. The extension of these estimation techniques into three dimensions has now been made possible by a successful integration of the volume modelling capabilities of 3D Component Modelling with proven 3D Geostatistical Techniques. The result is a powerful new technique for mineral ore reserves estimation in a practical, useable form. The technique allows direct geostatistical estimation of grade and quality values for precisely defined, irregular, realistic, geological, and mining shapes or volumes. This paper describes the two technologies, their integration and their application in practice to the estimation of mineral ore reserves. The paper closes with a discussion of the benefits provided by the new approach, in terms of accuracy, efficiency and practicality.

Jan 1, 1991

By H. Keith Henson

The purpose of this paper is to describe the possible application of two relatively new technologies: flat load cells, and improvement seeking computer programs (referred to in the literature as heuristic programs); to a very old problem, inventors control of ball mills. The combination of these two technologies seems most applicable to grate discharge mills operated closed circuit. It is possible that other applications such as controlling the inventory of autogeneous mills might also be found. Direct control of ball mill inventory has been the goal of a number of investigators over many years. Many patents and articles on the subject have claimed success, but operating installations are hard to locate. An excellent review of the advantages and problems of direct inventory control is contained in an article by Oswald and Ziegler (1). Figure 1 is a conventional representation of throughput vs. inventory with other factors such as slurry consistency and rock twee held constant. There are common sense, physical arguments? and experimental evidence supporting the existence of a unimodel curve of this twee? though direct measurement of the shape is difficult and how it moves as rock type changes is riot well known. Figure 2 represents the problem faced by all mass measurements of inventory, a tare weight of about 25 time the inventory mass. Worse yet, the tare is variable due to ball and liner wear and the Periodic addition of balls. The problem then breaks down into two parts: 1) obtaining enough mass

Jan 1, 1977

By William Gleason

"It has been more than 10 years since Montana Resources’ copper/molybdenum mine has had a lost-time injury at its site in Butte, MT. With more than 350 employees and an average production of about 15.5 Mt/a (17 million stpy), which includes 29.5 kt (65 million lbs) of copper and 4 kt (9 million lbs) of molybdenum, the mine’s journey to a decade of exemplary safety is an impressive feat that has required hard work, commitment and, most of all, leadership from every level of the operation.It has not always been an easy journey, nor has it been one without scrapes and bumps along the way, but it is one that has produced stellar results. Mike McGivern, vice president of human resources, and Pete Steilman, safety manager at the mine, spoke with Mining Engineering about how the operation transformed from a site that was accustomed to collecting citations for safety violations to one that is now collecting awards for its safety record.Simply put, Montana Resources has made safety a value and the people its top priority.The operations faced many predictable challenges in 2003, when the mine was being brought back online after three years of sitting in care-and-maintenance status. It had been shuttered in 2000 because of low commodity prices and high operating costs, and, in the three years that the mine was idled, the equipment became dilapidated, and some of it was no longer in compliance. Less than half of the workforce returned to the site for the restart, and the team was challenged with getting the gears turning again to produce copper and molybdenum. But the most daunting challenge of all of was keeping the workforce safe during the transition.In the first few years of operation the mine racked up citations from the U.S. Mine Safety and Health Administration (MSHA) at an alarming pace, so much so that in May 2006, Montana Resources received a letter from the MSHA District Office informing the company that the operation was being placed on the Potential Pattern of Violations list due to its excessive citation history and high rate of significant and substantial citations. It was clear that something significant had to be done to change the course of action at the mine."

Oct 1, 2019

By D. R. Gibbons

This morning I would like to speak to you about an area of chemistry that is enjoying a revival-organometallic compounds. This renewed interest, principally stimulated by defense needs, has already created new markets for the products of the mineral industry. Although the consumption of metals in these new products is modest at oresent, several hold promise of importance. Because this is a new and growing market, I am sure the Council of Economics is aware of many of its facets and is interested in new developments. Of course, the chemical industry has been a significant consumer of minerals for many years. I estimate that in 1957 the chemical-industry purchased a total of $1175 million worth of minerals as raw materials (not including fuels). This estimate can be broken down as follows: [Metals and metallic minerals $375 million Nonmetallic minerals (excluding hydrocarbons ) 330 million Hydrocarbons 470 million $1175 million]

Jan 1, 1958

By M. A. Bartkoski

Today?s surviving companies are being pushed to a heightened level of excellence due to market changes. Therefore, new business strategies must be explored. This paper offers a sequenced plan to retool, empower, and organize the entire team for a common goal. Integrity Process is an operating system that is very comprehensive and is integrated in every part of the business. It relies on a detailed prevention concept intertwined with accountability that produces individual efficiencies and team effectiveness. Integrity Process focuses on the importance between working from commitment motives versus compliance fears. The results are balanced in priority and truly yield a win-win for the owners, management, workforce, and the community. Integrity Process can and is being used in any industry that is challenged to optimize the relationship between people and process.

Feb 23, 2014

By J. F. Fitzpatrick

This paper examines the cost elements associated with changes to gold mining practice over the last decade that result from the changes in environmental regulation and the heightened governmental and public awareness of environmental issues. The main experience base is Pegasus Gold Corporation's flagship mine, Zortman/Landusky, located in the Little Rocky Mountains of Phillips County, Montana. This operation was among the first mines that were permitted under the 1974 Montana Metal Mining Reclamation Act. In 1974, the Montana Metal Mine Reclamation Act was enacted, creating a permit system for metal and industrial mineral mines for the state of Montana. The act established the content of mine permit applications and defined parameters for the reclamation of mining disturbances. The Act can be viewed as implementing legislation for Article 9, Section 2, of Montana's Constitution, which provides that "all lands disturbed by the taking of natural resources shall be reclaimed." Pegasus Gold Corporation's Zortman/Landusky mine was among the first mines permitted under the new Act. In 1978, the initial permit applications were submitted for Zortman and Landusky, and a full Environmental Impact Statement was prepared by the Montana Department of State Lands; permits were issued in 1979. When opened later that year, the anticipated mine life for the combined Landusky and Zortman operations was approximately 18 years, based upon a proven and probable ore reserve of 43.2 million tons. Zortman/Landusky was the first large-scale heap leach gold mine in the United States. Its distinguishing feature was, and remains, a remarkably low ore grade, now .016 oz/ton. The ore is economic because it requires neither crushing nor agglomerating to leach effectively. Approximately two years after the initiation of the state's regulatory process, the Federal Land Policy Management Act (FLPMA) was enacted, establishing a mine regulatory framework for lands under the administration of the Bureau of Land Management.

Jan 1, 1992

By Stephen H. E. Phillips

Geological and hydrological conditions in the strata overlying the Salado Formation vary considerably in the Carlsbad, New Mexico area. The first four shafts sunk at international Minerals and Chemical Corporation's property have been located in competent and essentially dry conditions, while other shafts on adjacent properties have had such adverse conditions that ground freezing has been chosen as the water and ground control technique for shaft sinking. At the location of the IMC No. 5 Shaft there has been extensive-erosion and salt dissolution in the Rustler Formation which has led to collapse of some zones of the strata. Both ground freezing and pregrouting were considered as alternative methods of stabilizing the extremely poor ground conditions and controlling the potentially very heavy water inflows it was decided that pregrouting the shaft was feasible and would offer substantial cost and time saving over a ground freezing technique. This paper describes the pregrouting techniques used and illustrates the requirement for flexibility in a grouting program so that it can be codified to reflect any new or additional information which is obtained during the progress of the grouting.

Jan 1, 1984

During foundry sand reclamation process development, molds formed from reclaimed chromite sand showed a rapid decline in tensile strength during thermal cycling tests. Because this characteristic could limit reuse of chromite sand in the foundry, the sand was examined in detail. Scanning electron microscopy, x-ray mapping, magnetic susceptibility, and x-ray diffraction were utilized to evaluate processed chromite sand. It was found that process variables such as binder composition, reclamation temperature, and processing method had a significant effect on the chromite sand particle surface. X-ray diffraction indicated a crystallographic change in the processed sands. Magnetic susceptibility also increased after processing. Diffusion of iron to the particle surface and increased surface roughness were identified as potential causes of the decreased tensile strength in the molds.

Jan 1, 1993

By Charles W. Daugherty, Eugene B. Waggoner

In the construction of recent subsurface projects, particularly mined openings and transit systems, it has been apparent that final costs were often greater than first expected. Because many overruns result from alleged differing site conditions, there was reason to suspect that pre-bid geotechnical investigations were inadequate for predicting subsurface geology. In 1982, nine federal agencies involved in constructing underground facilities funded the National Academy of Sciences' U.S. National Committee on Tunneling Technology (USNC/TT) in an effort to evaluate and clarify the relationship between geological knowledge and construction costs. That committee formed the special Subcommittee on Geological Site Investigations, which spent more than two years studying underground projects by examining contract documents and geologic reports, making site visits, and interviewing owners, designers and contractors. The study ultimately encompassed 84 mined tunnels and chambers and three deep shafts in the United States and eastern Canada. Data collected on geologic exploration, design and construction were analyzed and conclusions reached concerning whether and how site investigations need to be improved. The results of the study are published in two volumes by the National Academy of Sciences. Due to the recent completion date of the main report, it was not possible to prepare a summary for inclusion in the RETC Proceedings. However, the complete two-volume report, "Geotechnical Site Investigations for Underground Projects," can be obtained by writing or calling: U.S. National Committee on Tunneling Technology National Academy of Sciences 2101 Constitution Avenue, N.W. Washington, D.C. 20418 (202) 334-3136

Jan 1, 1985

By C. K. Skokan

Various geophysical tools have been tested over the last eight years to evaluate their usefulness in defining damaged rock zones in an underground facility at the WIPP site in New Mexico. These tools include direct current and frequency domain electrical methods and seismic tomography. The electrical measurements show a "drying rind" to exist around older excavations. Seismic tomography confirms that a rind of lower velocity has developed along walls. In combining these tools, a monitoring program has been proposed to observe long-term changes in bedded salt. Results from the monitoring of electrical data over a 2-year time period illustrate the applicability of the technique in an underground environment.

Jan 1, 1993

By Paul J. Henkels

Synthetic gypsum is the calcium sulfate co-product of a number of industrial processes. Synthetic gypsum utilization as an alternative to the naturally occurring mineral continues to grow in the gypsum industry. In particular, flue gas desulfurization (FGD) gypsum produced by the electrical utility industry has had a significant impact and a far-reaching effect on the gypsum wallboard manufacturing industry. This paper will discuss the various synthetic gypsum sources verses natural gypsum and highlight issues of use in gypsum wallboard and related products.

Jan 1, 1999

By C. M. Jones

The training program developed at Sierrita over the last twelve months has led to several significant improvements in both safety performance and productivity. Our most easily quantified results have been in truck productivity, where we have also experienced a 6% decrease in truck cycle times. We feel this is due to increased skill levels and awareness on the part of our operators due to our new training effort. The cycle time improvement has resulted in an increase in Truck productivity of 6%. Costs associated with productivity training have been $160,300. This includes program development and execution costs, as well as lost productivity during the training itself. These costs are offset by $1,400,000 in savings directly attributable to the increased skill levels of our technicians due to our training effort. As such, this represents a solid, high return investment at Sierrita.

Jan 1, 1998

By C. M. McCulloch

More and more mining underground is being conducted using the longwall method. Likewise, many new surface mines use area or mountaintop removal methods. These methods can have a significant impact on surface and groundwater resources. The overall study of the effects on surface and groundwater from mining is referred to as the probable hydrologic consequences (PHC) determination of mining and reclamation. Collection and interpretation of information concerning groundwater and surface water quality and quantity, as well as detailed geologic analysis, is required to adequately define the impacts of mining. This paper discusses the present day requirements and methodology of preparing a PHC for a large mining operation in the eastern coalfields.

Jan 1, 1995

By AMIT SHARMA, BIBHUTI BHUSAN MANDAL

This paper describes the vibration transmissibility characteristics of mining vehicle seats under dynamic conditions in an opencast iron ore mine. Magnitude and frequency contents of vibration signals on the seat floor as well as on top of the seats were measured to record the change during transmission. The conventional rigid seats were found to resonate at about 4 Hz, which coincides with the resonance of the human spine. The pneumatic suspension seats also proved to be more efficient in attenuating the overall vibration energy transmitted from the vehicle chassis to the human body.

By X. Zhu, L. Chen, R. Guru, M. Peiravi, M. Mohanty, L. Ackah, B. Xu

"The overall goal of this study was to develop a suitable flowsheet to extract rare earth elements (REEs) from coal ash. Only the findings from the first part of this study is being reported at this time. A total of fourteen coal samples of different ranks were examined for REEs concentration. An anthracite coal sample, originating from Pennsylvania having more than 700 ppm (in the coal ash) was selected for the REE extraction tests. The experimental program completed so far included high temperature leaching using nitric acid, followed by the solvent extraction tests. A 4x2x2 experimental design was used to conduct a total of thirty two high temperature leaching tests by varying acid molarity (at 4 levels), solid content (at 2 level) and leaching time (at 2 level). The highest LREE (light REE) recovery of 90% and HREE (heavy REE) recovery of 94% were obtained from the most optimum leaching test condition while maintaining the impurity recovery to the leachate at less than 40%. Solvent extraction experiments were conducted to recover the REE’s from the above leachate solution using a variety of organic extractants including, TBP, Cyanex, D2EHPA and their combinations. D2EHPA was found to be the best extractant during this SX text series providing nearly 99% recovery of REEs. INTRODUCTION The demand for rare earth element and other strategic metals (REM) in the world is rapidly increasing due to their use in a variety of high technology applications. More than 100,000 tons of rare earth oxides (REO) are being used worldwide on an annual basis. However, we have less than 10% of the world reserve of rare earth element (REE) mineral deposits in the US. More than 60% of rare earth oxide (REO) was imported to the US from outside (mostly from China) in the year of 2013. However, China’s institution of export quota has significantly reduced the supply of REMs to the U.S. Hence, new ways of producing REM and/or finding substitutes for those metals for the high-tech applications need to be invented/discovered in a timely manner. Coal Combustion Byproducts (CCBs), which are discarded as waste materials in most cases, are known to contain REEs (in low concentration) that could be extracted using a suitable process flowsheet. This may be a worthwhile route to pursue considering the short supply of REMs and the abundance of coal ash in thousands of ash ponds in the US. On an annual basis, more than 110 million tons of Coal Combustion Byproducts (CCBs) are being produced while satisfying our nation’s need for electricity (ACAA, 2014). However, less than 50% of these CCBs are being successfully used in various applications and the remainder is being dumped as waste materials in the landfills and ash ponds."

Jan 1, 2017

By R. S. Farinato

Thionocarbamate flotation reagents have enjoyed a niche position in the recovery of copper sulfides and activated sphalerites since their introduction in the mid 1950's (Harris, 1954). Thionocarbamates containing an allyl group (-CH2- CH=CH2), introduced recently Lewellyn, 1985; Nagaraj, 1988; Avotins, 1991), are used commercially as collectors for copper sulfides and activated sphalerite. Laboratory flotation tests and plant usage have demonstrated that allyl-containing thionocarbamate collectors exhibit certain unique properties that distinguish them from the corresponding dialkyl thionocarbamates. Spectroscopic (FTIR, XPS) and wettability studies of N-allyl iso-butyl thionocarbamate (AIBTC) and its saturated analog N-propyl iso-butyl thionocarbamate (NPIBTC) adsorbed on copper at pH 9 were performed in order to investigate whether there were any fundamental reasons for these differences. Flotation tests were carried out on chalcocite, copper ore and an activated sphalerite.

Jan 1, 1993

By T. J. Dudek

To be competitive in automotive applications, polymer composites must be processable by high production rate processes like injection molding (IM), reaction injection molding (RIM), structural rim (SRIM) and compression molding. With current fiber reinforced composite materials, performance properties are sometimes compromised to make them compatible with these processes. This is done by decreasing the amount and length of the reinforcing fiber and the viscosity and molecular weight of the polymer matrix. Sheet molding composite (SMC) and thermoplastic polymer blends are examples of polymer composites which are cost effective in many applications and meet the high speed processing requirements for automotive parts.

Jan 1, 1993

By J. Luo

A major design problem for upper seam longwall gate roads that are to be constructed in a multi-seam environment is to predict the effects of stress field changes created by interaction. To quantify these effects, case study data were analyzed to develop empirical stress transfer relationships between seams for both longwall and room and pillar mining. Data analysis showed vertical movement and roof characterization in the upper seam to be controlling factors in damage prediction and, therefore, gate road planning and design. CMRR (Coal Mine Roof Rating) was correlated with the multi-seam roof characterization systems previously used. A WINDOWS-based software package named UGLY (Upperseam Gateroad Longwall Stability) was developed. Results from selected case studies were correlated with upper seam stress predictions.

Jan 1, 1997

By P. R. Taylor

A review of the advantages and disadvantages of plasma technology for metal and mineral wastes is presented. Examples of the use of plasma systems are given and possible future uses are outlined. Among the potential uses are treatment of electric arc furnace (EAF) dusts, the vitrification of nuclear wastes and the removal of toxic metals. Over the past few decades, plasma technology has been studied for potential applications over a wide range of metals/materials processing areas. One promising area of plasma technology applications is the treatment of industrial hazardous waste. The potential generation of hazardous and toxic waste by various industries has become a matter of public and political awareness. Environmental regulations have put stringent toxicity emission limits on disposable waste streams. An intensive research effort is currently underway in the area of hazardous waste treatment.

Jan 1, 1994