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By S. Mathur

The southern Florida phosphate deposits that will be mined in the future contain significant amounts of dolomite. Because high MgO levels are undesirable in phosphoric acid production, several flotation schemes for the removal of the dolomite have been attempted. Alternatively, selective flocculation has been suggested as a potential process. A high MgO rock was simulated with a 30:10:60 mixture of apatite, dolomite and silica, respectively. Single mineral selectivity was observed in the apatite-silica and dolomite- silica systems using Polyacrylic acid (PAA) and Poly(ethylene oxide) (PEO) flocculants, respectively. However, no single mineral selectivity was observed in the apatite-dolomite system using PEO. Heteroflocculation, suspected to be the major reason for the loss of selectivity, was minimized by the addition of a site blocking agent (SBA), consisting of a lower- molecular-weight fraction of PEO. Process parameters such as size reduction schemes, flocculant/SBA dosage and pH were investigated to achieve the desired separation. The selectivity obtained in binary mixed-mineral tests was also achieved in the ternary mixed-mineral system, namely, the apatite-dolomite-silica system. In this report, surface chemical characterization of the samples and their flocculation behavior are discussed.

Jan 1, 1995

By Terry McNulty

DOUG HALBE: I've decided that we're going to change tactics here and we're going to be nice to people from now on. [Co-chair makes gesture of intense disbelief; laughter] I've also decided who's not going to be a co-chair next year. [laughter] We thought we'd get a couple of experts for our next presentation: some people with a lot of experience. We've asked them to tell us some of the things that all of you operators out there might be able to apply immediately to your plant. Our next two speakers have a tremendous amount of experience, and I think you'll find what they're going to say is highly pertinent to most plants. I looked through their paper and found some things that I could have used in the plants I operated in the past. Our first speaker is Terry McNulty. A lot of you know Terry. He was with Anaconda for a number of years as director of research. He then was president of Hazen Research. I'm going to continue with our new custom of saying nice things. Terry is the guy that I call when I don't know something, and he's always got the answer. SPEAKER: Who do you work for, Doug? [laughter] DOUG HALBE: Remember that we're being nice to people here, Joe. I know that's a stretch. [laughter] TERRY McNULTY: Thank you, Doug. I'm a little bit mystified by this sudden switch of tactics just before I get to the podium. Doug's been a good friend for a lot of years so I guess I do have to be nice. I won't say anything deprecatory about him, but I would have to comment that the observations made by earlier speakers have been far too generous. [laughter] During nine years of consulting as a mineral processor and extractive metallurgist, I have often conducted audits of the performance of client's plants. Usually these audits have been ordered by the plant management in hopes of identifying opportunities for improving processing efficiency or reducing costs. Some of the audits, however, have been financed by the Electric Power Research Institute (EPFU) and member utilities with the objective of

Jan 1, 1998

By D. C. Edwards

In an age where customer service and quality drive today's industry and business, no service or product is exempt from these demands. Industry and business are streamlining everything from people to equipment and today have a heavier reliance on the performance and quality of their assets and equipment, (one of the keys to staying competitive). In the mining process industry, the centrifugal slurry pump is a key piece of equipment that keeps product moving and aids in generating revenue for its owner. The continued improvement and customer success lies in a team effort between the mining industry and the pump manufacturers. We, the pump manufacturers, need to keep improving our designs to further extend the life of our pump with fewer failures and promote to our customers proper maintenance of the pumps to continually keep unexpected failures to a minimum. Strict equipment maintenance, as thoroughly demonstrated by the military, is key to the long life and success of any piece of equipment. In the often harsh duty of the centrifugal slurry pump, maintenance is something that requires "attention to detail". No area of the pump is exempt from attentive maintenance. Here, discussions will focus on the areas of the mechanical drive end, wet end, seals, and extended pump shut down and start up. There has not been a slurry pump designed to maintain or repair itself. So in effect, each pump warrants able bodied maintenance persons to maintain them who continually observe all the rules of safety. Prior to any maintenance discussion or action, the issue of safety should always be addressed. Here, as with everywhere, the same rules apply. Work at a safe pace, note all safety precautions, use associated safety equipment and personal protective attire, observe all tagout and lockout procedures, and most importantly, be aware.

Jan 1, 1996

By Jeffery Denit, Steve Hoffman, Van Housman

The Environmental Protection Agency (EPA) is in the early stages of developing a national mining waste program. Our goal is to develop a mining waste program that will be state implemented, multimedia in nature, flexible, utilize and enhance existing state programs, and protect the environment. The Agency appreciates the cooperation the mining industry is providing through its participation in the Policy Dialogue committee on Mining and by providing the Agency with technical data. The following is a discussion of what led to the development of a national mining waste program, the agenda initiative to evaluate Toxic Substances Control Act authority in phosphate manufacturing, and the important steps being taken through the Policy Dialogue process to frame and discuss issues. EXTRACTION AND BENEFICIATION OF ORES The Resource Conservation and Recovery Act of 1976 (RCRA) and subsequent amendments created a framework for the regulation of hazardous wastes under Subtitle C and nonhazardous waste under Subtitle D. In 1978, initial regulations were proposed for hazardous waste management units under RCRA. These identified a universe of special wastes that were large volume, low hazard and less amenable to Subtitle C control techniques. EPA noted that waste materials from the "extraction, beneficiation and processing of ores and minerals m fit these criteria. In October 1980, Section 3001 of RCRA was amended. This Bevill amendment excluded solid waste from the extraction, beneficiation and processing of ores and minerals from regulatory control under RCRA's hazardous waste Subtitle C. This was done pending a report to Congress and a regulatory determination regarding the Subtitle C status of these wastes. Thus in November 1980, EPA published an interim final amendment to the RCRA Subtitle C regulations to reflect the Bevill amendment. RCRA requires EPA to perform studies and make reports to Congress regarding the management methods and potential hazards of managing waste. RCRA also calls for a regulatory determination regarding whether Subtitle C (hazardous) or D (non- hazardous) controls are warranted for these wastes. In December 1985, EPA submitted a report to congress entitled, “Wastes from the Extraction and Beneficiation of Metallic Ores, Phosphate Rock, Asbestos, Overburden from Uranium Mining and Oil Shale." In that report, EPA found that some mining wastes exhibit hazardous characteristics, that the range of risk from mining waste is broad, and that waste management practices have caused environmental damage. In July 1986, EPA published a regulatory determination based on information gathered in the 1985 report to Congress and comments from interested parties. In the report, EPA concluded that RCRA Subtitle C regulation of extraction and beneficiation wastes was unwarranted because mining wastes tend to be disposed of in arid climates, waste volumes are high, and facilities and wastes are located in sparsely

Jan 1, 1992

By William G. Doepken

After 15 years of production, 91 Mt (100 million st) of ore mined and nearly 227 kt (500 million lb) of molybdenum produced, Climax Molybdenum Co.'s Henderson Mine and Mill are being modernized as a new mining level is brought on line. The $40 million investment in mine development and plant modernization positions the Henderson complex as one of the largest, low-cost primary molybdenum producers for the next 15 years. Henderson history The Henderson Mine and Mill facilities are located on the east and west flanks of the Continental Divide about 80 km (50 miles) west of Denver, CO. The underground mine and surface mill sites are linked by 16 km (10 mile) of railroad tunnel and 8 km (5 mile) of surface trackage. The mine, railroad and mill were built between 1968 and 1976 at a cost of $500 million. Each has operated at various levels of production over the past 15 years. The Henderson Mine was originally developed using a highly mechanized, panel caving mining system. Over the past 10 years, mining methods, equipment and railroad operations have been improved to position Henderson as one of the most productive and lowest cost underground mining operations. At the same time, the mill and concentrator facilities were upgraded to reduce costs and improve product quality. During this time, manpower was reduced from 2000 to 560 employees. These 560 people increased productivity to 54 t (60 st) per total manshift. They reduced operating costs by 50%. And they dramatically improved safety performance. However, as the 1990s approached, the modernization of the Henderson mining and milling complex and the development of the new 7700 mining level became the primary goals to guide Henderson into the 21st century.

Jan 1, 1991

By Larry Whittle

Gold milling activities generate waste streams containing dissolved metals and cyanide, among other contaminants, that require some form of treatment prior to discharging to the environment. To date, this treatment has involved the destruction of cyanide through natural degradation, chemical oxidation, or a combination of both followed by the precipitation of metal hydroxides. Although these processes have been proven to be capable of achieving. regulatory levels for metals and cyanide, they often generate significant levels of cyanate and, at times, ammonia, that may be toxic to rainbow trout and thus undesirable for regulatory compliance. Tallon Metal Technologies Inc. (Tallon) has developed Vitrokele™, a chelating resin that has the ability to capture metals (including gold), both total and weak acid dissociable cyanide, as well as thiocyanate from both slurries and solutions. The loaded resin is eluted and returned to the recovery circuit while metals and cyanide are recovered from the eluent stream. This process was demonstrated at pilot scale at B.P. Resources' Hope Brook Gold Mine in Newfoundland, and more recently at Canamax's Bell Creek Mine near Timmins, Ontario. The results from these pilot programs showed metal and cyanide recoveries of 99% or more with the concentration of cyanide and metals in the effluent reduced to levels with minimal or no toxicity to rainbow trout. Furthermore, neither cyanate nor ammonia were generated from the process. The loaded resin was effectively stripped and re-introduced to the recovery circuit; cyanide was captured in the eluent stream and made available for recycling to the mill leaching circuit; and metals were captured for re-use, sale or disposal. This paper summarizes the results obtained from the pilot tests at the Bell Creek and Hope Brook Gold mine sites.

Jan 1, 1992

By W. J. Miles

Industrial mineral by-products occur as a result of mining and processing a primary mineral product. By-products result from concentration and separation of accessory minerals during processing or from the primary mineral during processing, for example dusts. Many companies have found it rewarding to evaluate mineral by-products from their operations and determine potential products and applications. By-products need to be evaluated for physical and chemical properties to determine possible applications and markets. Market studies are needed to determine application specifications, price structure of the market, competitive products, and to determine marketing regions. The by-products need to be evaluated for beneficiation and processing to meet these market requirements.

Jan 1, 1985

By R. C. Timberlake

An understanding of the Florida Phosphate Industry, the mining practices and extraction processes and the historical development of the Industry, is essential to any consideration of reclamation. In the earliest days of the Industry, phosphate rock was produced by screening the phosphate pebble from the matrix. The waste, which consisted of overburden, clay, sand and fine phosphate, and was called "debris", was disposed of onto, either the adjacent surface area, or into mined-out pits. Since the Central Florida area was sparsely settled in those early days, there was no complaint from residents about contamination of streams or the resulting spoil piles - environmental concerns were non-existent. The development of the flotation process in the 1930's and the implementation of the flotation process in the early 1940's was a significant technological breakthrough in the Industry. This technique made possible the extraction of fine phosphate particles, and doubled the recovery of phosphate values from the matrix. However, the implementation of the flotation process produced a new waste disposal problem.

Jan 1, 1978

By D. E. Piggott, B. E. Hartmann

The thought of constructing an intake shaft five miles from the shore and 142 feet below the surface of Lake Huron from the bottom up sounds like a questionable venture. Why would one want to raise a shaft from the bottom at the end of a 16 foot diameter, six mile long tunnel to within six feet of the bottom of Lake Huron? The answer lies in the fact that Lake Huron is seldom a tranquil lake. The construction period and workable days from the surface are limited. Two previous attempts to construct this intake shaft by conventional means had been thwarted by lake storms. These approaches were circular sheet-piling cofferdams with the intention of sinking a 30 foot OD, five foot wall thickness concrete casing in the center. However lake storms, particularly in the months of November and December, proved disasterous. The last attempt was halted in December 1970 when three of the seven circular cofferdams on the north side were destroyed by pounding waves. Then, due to the nature of the technical difficulties and limited construction schedule time, it seemed desirable to devise a way in which construction could proceed without being too lake-sensitive. Obviously, if men could work from the tunnel and proceed upward toward the bottom of the lake, not having to worry about the soil collapsing and bringing the lake in on their heads, the construction would be unimpeded by adverse weather. The answer to this, however, required techniques beyond the ordinary. Approximately two years previous to the start of this shaft, nine shafts had been efficiently constructed on the same project site

Jan 1, 1974

By Robert J. Timko, R. Lincoln Derick

The Bureau of Mines evaluated the integrity of escapeways in a three entry underground coal mine. A center conveyor belt entry (secondary escapeway), was flanked by an intake (primary escapeway) and a return entry. Diesel equipment was used throughout the mine for material and personnel haulage. A carbon monoxide monitoring system, tied to a data recording computer on the surface, was deployed throughout the belt entry and at selected sites in the intake and return entries. Previously, the company had a fire of unknown origin in another mine, which prompted an interest in the performance of their escapeways. An initial, qua1itative evaluation was performed by burning approximately 14 kg of coal at the mouth of the intake entry. The first test was followed by a similar burn at the mouth of the belt entry. These initial trials showed a high quantity of leakage between entries. In several follow-up evaluations, simulated fires, using a tracer gas, were set in the intake and belt entries. Tracer gas concentrations were obtained in all entries at four different underground locations. The results of these tests showed that permanent stoppings could not guarantee isolated, contaminant-free escapeways.

Jan 1, 1989

By G. F. Ayakwah

Point load strength (Is50) and slake durability (ID2) indices provide a measure of the strength and durability of rock fragments and are related to the alteration intensity and frictional resistance of the materials. Samples were collected from the rock piles, alteration scars and debris flows at the Questa mine with the purpose of examining relationships between Is50 and ID2, mineralogy, chemistry, weathering, hydrothermal alteration, and other geotechnical parameters. The Is50 from the various rock piles ranges from 0.6-8.2 MPa and the ID2 ranges from 80.9-99.5%. The Is50 and ID2 results indicate that the samples from the debris flows are stronger (average Is50= 4.0 MPa and ID2= 98.4%) than the rock-pile samples and that the alteration scar samples are weaker (average Is50 = 2.8 MPa and ID2 = 89.2%) than the rock-pile samples, but still most of these rocks are strong in terms of their Is50 and ID2. The Is50 decreases as the degree of alteration increases in some rock pile and alteration scar samples, but not in all. However, the majority of the rock fragments within the rock piles still indicate high strength, even after 25-40 years of weathering.

Jan 1, 2009

By F. C. Schwerer, C. R. McKee, J. C. Seccombe

Production of methane from coal seams requires hydrofracturing, and the length of a hydraulic fracture determines we11 spacing. Since the volume of fluid injected is known, the fracture length is the volume divided by average width and height. If the fracture is contained in the known height of the seam, then fracture width becomes the major factor con- trolling length. Width is proportional to coal compressibility; bulk compressibility is known to be larger than intrinsic compressibility. A method is given here to measure in-situ compressibility (a) from transient pressure testing. Theory linking flow in porous media with rock mechanical properties is reviewed. A consistent derivation of the porous flow equation is given incorporating 3-D deformation and the effective stress parameter "st' linking changes in effective stress and pore pressure. The relations for "st' in terms of a and intrinsic compressibility (ai) are substituted into the field measured porosity-compressibility product (net) and solved for a, the constrained matrix compressibility. In a field example, using 4 wells with an anisotropic analysis, the ratio of major to minor permeability was 17 for the Pratt A seam. a was found to be 6x10-5/psi as opposed to the laboratory value of 1.4x10-6/psi.

Jan 1, 1986

By A. D. Davis, C. J. Webb, T. V. Durkin

This project took a watershed approach in the evaluation of water-quality impacts from past mining activities and current restoration projects in the Bear Butte Creek basin, a small and well-defined drainage in a heavily mined area of the northern Black Hills. The basin contains numerous inactive and abandoned mines, as well as a heap-leach surface gold mine. Bear Butte Creek normally loses all of its discharge to sinkholes in the Madison Limestone aquifer. Thus, it can affect the water quality of this regionally important water resource. Water-quality data were analyzed, stream surveys were conducted and two abandoned-mine restoration projects were monitored to evaluate the effectiveness of the watershed approach and to identify practical remediation techniques that could be applied to other watersheds. A geographic information system (GIS) was developed to organize information on stream quality, abandoned mine locations, and other geologic and hydrologic data. The watershed approach toward assessing and reclaiming abandoned mines appears to be effective when compared to a point-source approach that might improve water quality at specific sites but not result in significant overall improvement to the watershed because of adjacent sources.

Jan 1, 2000

By R. R. Smith

The meaning of the title, "Blank Piece of Paper," refers to the need for management to take a completely fresh viewpoint to the problems facing our industry. These problems are so severe and some so new that conventional thinking may not be adequate to resolve them. Innovation has to be a part of every company's approach to the solutions, our concept is to start with a "Blank Piece of Paper.' The objective of 'this paper is to outline steps which can be taken to improve the profitability of a mining business. This is not an examination of technical solutions to individual problems, but rather recommendations for overall change in management thinking. This philosophy is based on our actual, hands-on experience in major open pit operations worldwide over the past 25 years.

Jan 1, 1987

By Hamid Maleki

A geotechnical monitoring program has been implemented at Energy West Mining Company for enhancing site-specific evaluation of longwall stress conditions. This program consists of underground measurements at five locations in two neighboring mining districts located in the Hiawatha and Blind Canyon Coal Seams under moderate to deep cover. Within the last five years, additional measurements, including data on recorded seismic events and face conditions, have been incorporated into the data collection program together with detailed geologic mapping of longwall gateroads. In conjunction with the measurement program, the authors have completed detailed boundary-element stress analyses of the mine plans. Models have been calibrated using the data from in-mine instrumentations and then routinely used for evaluation of mine plans at depths approaching 2,600-ft. The work has improved our understanding of load transfer, seismicity and yield pillar performance. It has identified areas of potential increased stress levels at certain longwall face positions and provided guidance to measures that could be considered to mitigate the potential for these increased stress levels.

Jan 1, 2009

By R. M. Hays

Jan 1, 1980

By M. A. Trevits, R. J. Matetic

Mining operations have long been accused of causing a disruption to local, domestic and agricultural water supplies. More recently, concern for water supplies has increased with the advent of high-extraction mining techniques, namely longwall mining. Theoretically, any water-bearing zone in the overburden above a high-extraction mining operation may be affected by mining. In some cases, a confining bed may be fractured causing a loss of water to a particular zone. In other cases, increased fracture permeability may enhance the ability of an aquifer to transmit and deliver water. Unfortunately, only a limited number of studies have been conducted that characterize hydrologic changes and also quantify the magnitude of mining-induced subsidence. The US Bureau of Mines (USBM) conducted such a study at a mine site in Greene County, PA. A total of eight water wells were drilled, and hydrologic parameters, such as specific capacity, transmissivity and well yield, were determined both before and after mining. Electronic water-level recorders were installed on each water well to provide continuous observations of water level fluctuations.

Jan 1, 1993

By Mulong Yu, Yosry A. Attia

Beneficiation of high magnesium Florida phosphates requires ultrafine grinding to liberate the dolomite (the main source of magnesium), and a separation process capable of dealing with ultrafine sizes such as selective flocculation. The objective of this study was to investigate the feasibility of separating dolomite from apatite ultrafines by selective flocculation. To achieve this objective, selective polymeric reagents to either dolomite or apatite must be first designed and synthesized. This challenging task was accomplished by carefully selecting complexing/chelating agents which are selective to either the Ca or Mg ionic sites on the minerals, and incorporating these reagents into the structure of long chain water soluble polymers to obtain either selective flocculants (with high molecular weight, MW, polymers), or selective dispersants (with low MW polymers) to either the dolomite or the apatite particles. Synthesis and testing of these polymers on individual and mixed mineral slurries, and on a sample of natural high magnesium phosphate ore, have been attempted and the results are described in the paper. The preliminary results showed encouraging signs for the feasibility of selective flocculation separation of dolomite from apatite.

Jan 1, 1993

By A. E. Ketler

Powerful, yet inexpensive, personal computers running Windows-95 operating systems provide powerful mine-wide monitoring capabilities when properly engineered. Long awaited conductivity over LAN, phone and Internet links provide new dimensions for sharing information throughout an operator's organization, in- deed around the world. On-line data analysis, archival data storage and historical trend viewing generate shared inputs to production, safety and maintenance personnel. Five years in development, Rel-Tek's new EZ-Trol/W-DX system was engineered around the pilfalls of a Windows environment. It now offers higher speeds, 3D animated graphics and long distance telemetry - all with better reliability than ever before possible. The ubiquitous DDS utility inherent in most Windows was discarded in favor of a lightning fast RAM format. Several ponderous interpretive programs were redesigned into a single compiled entity, thus avoiding the overhead from message conversion, handshaking and transfer. To make the system user friendly, a 'Wizard" utility helps operators set up and reconfigure their systems on site. In-mine data acquisition telemetry was also re- vamped, incorporating a unique noise avoidance scheme, dubbed the "DX" bus - enabling longer distances and higher reliability. 12- bit analog conversion provides the enhanced resolution needed for field scaling auto-cal sensors. By mid '96, eight EZ-TROLMI- DX systems were up and running, several for more than a year. Factory updating and assistance are possible over a phone or Internet link. Our factory testing of components routinely includes actual operation at 2400 BAUD over 14 miles of twisted pair wires.

Jan 1, 1997

By E. S. Cheney

The sandstone-type uranium deposits of the Gas Hills occur in the arkosic, lower Eocene Wind River formation on the southern edge of the Wind River Basin. The d S34 values of pyrite cement associated with uranium mineralization are-significantly lighter than values for syngenetic-diagenetic pyrite nodules, therefore the H2S responsible for the precipitation of the epigenetic pyrite and uraninite was produced [t]epigenetically. These values are much lighter than the values of H2S from neighboring oil fields. The presence of biogenic pyrite in meta-igneous Precambrian cobbles indicates that these cobbles are not remnants of former; vein-type uranium deposits.

Jan 1, 1964