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By Gary L. Simmons

Many large (refractory) sulfide gold resources exist in Nevada and other parts of the world that are not amenable to conventional flotation concentration using air as the flotation gas medium. Over the past five years Santa Fe Pacific Gold Corporation (SFPG) has investigated flotation process options to economically treat refractory ores and resources of this type at its Lone Tree and Twin Creeks mines. Conventional flotation technology applied to the original high-grade gold resources at Lone Tree and Twin Creeks was initially unsuccessful. Review and analysis of auriferous (gold-bearing) iron sulfide mineralogical characteristics and flotation ..:hemistry provided a fundamental understanding that led to the development of a new flotation process that SFPG refers to as N2 TEC. This paper discusses the development of this technology and compares N TEC results with conventional flotation practice.

Jan 1, 1997

By I. K. Gilmore

PCS Phosphate operates an open-pit phosphate mine in the central coastal plane of North Carolina. The company has mining and refining facilities located on the south shore of the Pamlico River. Phosphate ore is recovered at the Aurora facility by open-cast mining techniques. Walking draglines and bucketwheel excavators remove the overburden and mine the phosphate ore. The mined ore is slurried about 8 km (5 miles) to the processing plant. At the plant, the phosphate ore slurry is passed through screens to remove material coarser than 2 mm (10 mesh) and then pumped through hydrocyclones to remove material finer than 75 mm (200 mesh). The resulting phosphate and sand mixture is treated with various reagents and subjected to an anionic flotation process. A cationic flotation process removes the sand from the final phosphate concentrate.

Jan 1, 1995

By B. Stewart, J. R. Warneke

The productivity of underground mines has increased dramatically since the introduction of continuous miners. A variety of new hazards have developed as a result. In the spring of 2004, Mine Health and Safety Administration (MSHA) held a workshop to brainstorm ideas to decrease the number of injuries associated with continuous miners. One of the main areas of discussion at the workshop was “trailing cable-handling injuries.” The method of handling the power cables over the years has changed very little while the technology and uses of continuous miners has advanced dramatically. This paper will discuss the main ideas brainstormed at the MSHA continuous miner (CM) trailing cable handling workshop and the history and root causes of cable-handling injuries, as well as proposed ideas developed at the National Institute for Occupational Safety and Health (NIOSH) to alleviate some of the cable handling issues.

Jan 1, 2006

By J. Mastoris

The growing environmental awareness and the need for providing social service to the community, urge the primary sector companies (such as mining) to find new solutions, by adjusting their operations with the special, local conditions and meeting everyday problems in practical ways. We hereby present a real case of re-design of an open pit, closed-bench type industrial minerals (clay) excavation, for the purpose of rehabilitation and utilisation as a water reservoir. The potential use of rainfall water was studied on the basis of covering the irrigation needs and improving the living standard of the neighbouring farmers and also as a project or recreational development of the area by shaping a wetland. The experience from the project progress and the reservoir use has been positive to date and the reclamation plan seems to have the acceptance of the local community.

Jan 1, 2002

By R. N. Torbin

Foster-Miller has recently developed a new concept.for a highly specialized shaft lining system. This innovative shaft lining system uses a continuous slipforming placement technique. lining the shaft from the bottom up such as in a raised bored shaft. Although this part is not unique, the concept is designed to use polyurethane foam instead of concrete for the liner material. Furthermore, the concept is designed to attain rates of advance of 30 m/hr. The polyurethane foam liner is designed to be thinner (100 mm) than a conventional concrete liner (300 mm). It will eliminate the high cost associated with the erection and operation of an on-site concrete batch plant. The system will be designed to be operated remotely, requiring few personnel for its operation. This system (or parts of it) may be appropriate where fast construction speed is required or where a jointless liner is needed.

Jan 1, 1988

By Hugh E. Cronin, John Ramage

The recommendations resulting from a Dispute Review Board (DRB) hearing of a contract dispute are being challenged more and more frequently. This paper explores possible causes based on the authors’ experiences. Challenges facing the DRB process include: The DRB process is starting to lose some of the informality and flexibility. Both owners and contractors appear to be putting too much weight on a board recommendation on a dispute. DRB’s do not make “decisions,” they provide recommendations for dispute resolution to both parties. The DRB process is not just for contractors to present an unresolved issue to a board hearing. Owners can also initiate a request for a hearing on a disputed issue. For the DRB process to remain a viable element of the successful construction project, confidence must continue to be maintained in a process that is intended to work on behalf of both parties to the construction contract.

Jan 1, 2003

By R. Vergunst, E. A. Devuyst, G. Robbins

By the middle of 1989 Inco will have applied its patented cyanide removal technology to seventeen commercial operations. Removal of cyanide from CIL slurry tailings is applied at Equity Silver and Inco's new 1.200 mtpd mill at Inco/Golden Knight. Detoxification of CIP tailings is carried out by Colosseum California (3.600 mtpd), Canamax's Ketza River (360 mtpd) and Westmin's Silbak Premier (2000 tpd) operations. Repulped tailings from Merrill-Crowe flowsheets are treated at Total Erikson's Mount Skukum (300 mtpd) and Skyline's Johnny Mountain (200 mtpd) mills and barren bleed at Inco/Queenston's McBean mill (500 mtpd). Lynngold's MacLellan mill (1800 mtpd) and ERG (40.000 mtpd) treat pond supernatant water. Plating shop cyanide effluents are decyanized at Kuntz Electroplating and two other plating shops in Ontario. Details regarding some of the above operations are given. Operating and capital cost estimates for various treatment options are discussed.

Jan 1, 1989

By Herbert Pöllmann

The mineralogical and chemical compositions of various waste materials undergo different reactions when treated thermally The heavy metal contents can be bound to stable phases. These minerals are called reservoir minerals. The main property of these minerals is the stability in their geochemical surrounding containing the heavy metal cations and anions. Examples for these minerals are apatites, spinels, garnets, perovskites and also water containing minerals like ettringites, metal-metal-hydroxi salts, jarosites and zeolites. When the chemical compositions of different wastes are mixed according to the compositions of the new formed minerals, a probable reuse of these wastes can be obtained. The use of waste incineration ashes for the production of cementitious binders and the use of flue gas desulfurization products for cement additives are shown. Also the transformation of highly contaminated materials into stable reservoir mineral assemblages are shown including the study of stabilization and immobilization techniques.

Jan 1, 1998

By D. Eyde

The zeolites review arrived too late for the June issue. The natural zeolite industry continues to grow even as some companies look for the exits. Production for 1993 was estimated at between 42 and 44 kt (46,000 and 48,000 st). That is between 7 and 9 kt (7700 and 9900 st) above 1992 production. GSA Resources, Saint Cloud Mining, Steelhead Specialty Minerals, Teague Minerals, UOP and Zeotech all reported continued growth last year. At the same time the East-West Minerals' Eastgate mordenite mine, and American Resources' Ash Meadows clinoptilolite operations both shut down their processing plants and are attempting to sell the mines and facilities. In addition, Tenneco Minerals continued its attempt to sell the Mud Hills clinoptilolite deposit. Unimin entered the natural zeolite industry through its acquisition of several properties of Aimcor. The properties included the Ben-Jel bentonite and Castle Creek clinoptilolite deposits and processing facilities near Caldwell, ID

Jan 1, 1994

By Terry M. Hertel

Zortman Mining has spent approximately three years evaluating the metallurgy of the sulfide ores from the mining area of the possible expansion project. As the test program proceeded, an interesting series of events took place which changed the scope of the work. During the agglomeration work, one of the control columns was inadvertently set up without the addition of lime to the material prior to loading and subsequent leaching. The gold recovery from this column was comparable to those columns that had a lime addition of 10 pounds per ton of ore. In fact, the gold recovery curve had a much steeper slope than those of the other columns. Furthermore, the pH of the pregnant liquor from the "no lime" column recovered to typical levels as fast as the solutions from the "lime" columns. These observations led to the concept that rinsing the ore with water prior to cyanide leaching could be advantageous to the heap-leach process.

Jan 1, 1992

By Betty L. Gibbs

Mine planning and scheduling done with computer programs is possible only after extensive work has been completed to define the geologic extent of an ore body and an overall mine design. Mine planning methodology on computer can vary from computerized engineering tasks through systems which completely optimize a plan with little input from an engineer during the actual scheduling process. However, a strong emphasis is placed on producing practical mining sequences which may be "best" rather than "optimum". This section offers several viewpoints on the planning process using computers. Interactive planning and scheduling systems are attractive for many companies because they are easy for engineers to understand, and the results are acceptable. The engineer develops an open pit mine sequence by trial and error using interactive graphics. The results of this approach can usually be improved. A computer program can help an engineer make many trials in a short time period and provide a higher level of confidence that a "best" plan has been generated.

Jan 1, 1989

By Michael G. Strominger, Anthony E. Gross

The development of precious metals ore agglomeration with a cement binder, by the U.S. Bureau of Mines, has allowed the economical heap leaching of low grade gold ores (<0,05 oz/ton) over the last decade, Even with the Bureau of Mines technology, numerous operations continue to experience channeling and blinding problems. A research project was undertaken at Nalco Chemical to address situations where improved agglomeration is needed, By increasing the incorporation of fines into the agglomerates,the segregation of ore by size which occurs from handling will be reduced and channeling minimized. A stronger agglomerate will reduce fines migration during leaching and prevent blinding of the heap, Both of these changes will give an even flow of barren solution throughout the heap and give solution contact with all of the ore. This paper presents the development of polymeric agglomeration aid, Nalco 9760 which has given a higher rate of and a higher total gold recovery in plant evaluations.

Jan 1, 1990

By S. K. Kawatra, S. J. Ripke

Finely disseminated iron ores compose much of today&apos;s reserves. After removing the silicate gangue, the resulting fine iron oxide concentrates require pelletization with a binder to enable transportation and reduction. Binders can be used more efficiently if their binding mechanisms can be completely understood. Typically, bentonite clay is needed as a binder to improve the strength of the pellets. Bentonite is an effective binder at a relatively low cost, but costs could be reduced further by replacing bentonite with even lower-cost binders, such as high-carbon Fly-Ash Based Binder (FBB). In this study, it was found that bentonite binds by a physical mechanism, while FBB binds by a chemical mechanism. These mechanisms were determined to be incompatible. Partial replacement of either binder with the other reduced dry magnetite pellet compressive strengths below the industrially acceptable value of 22.2 newtons (5 lbf). Activators and accelerators that activated the fly-ash deactivated the bentonite. The incompatibility of these two binders is explained.

Jan 1, 2000

By K. Eric Livo

The Front Range Infrastructure Resources Project (FRIRP) of the U.S. Geological Survey (USGS) is currently using Landsat Thematic Mapper? and air- borne-visible-infrared-imaging-spectrometer (AVIRIS) data along with planned thermal-infrared data and interferometry-synthetic-aperture radar (IFSAR) data to assess the industrial-minerals quality and quantity along the Colorado-Wyoming Front Range Urban Corridor and to characterize surrounding areas. Landsat? satellite data show synoptic views of the corridor, which may readily be used to identify potential regions of permissible terrain, such as river drain-ages, pediment surfaces, upturned lithology, and bed- rock exposures, where various types of deposits may occur. Descriptive models of these deposit types are used to define the physical features that need to be recognized and characterized. In the case of Landsat? data, the measured light is either reflected or partly absorbed by surface materials, depending on the wave- length of the light, which allows coarse mineral classifications to be made.

Jan 1, 1999

By D. Harney

Accurate measurement, tracking, and planning are vital for efficient utilization of energy in any mining operation, the major focus of this paper. This can be done with a number of assessments: 1) accurately measure KWH usage and track peak demand periods first; 2) identify the electrical equipment that affects your usage and the conditions that require it to be running; 3) remotely monitor and control as much equipment as possible, especially larger pieces of equipment; 4) with your utility determine that you are on the most suitable rate for your usage profile, then understand how your utility company calculates your electrical bill; 5) recognize how production affects energy usage and utility costs; 6) keep historical records of everything you monitor; 7) make information, live and historical, available to everyone; and finally, with the knowledge of your equipment and energy needs, automate controls that you have identified to optimize your energy usage and time of usage.

Jan 1, 2007

By Nancy Bingham

The mining industry’s image is molded by what the public knows, or thinks it knows about mining. As Caterpillar prepared for the production of its educational video, Common Ground, the public’s perceptions about mining needed to be established. Before we could educate people about mining, we had to find out what they already thought. As those perceptions were analyzed, we were able to narrow the video’s focus to relevant, realistic approaches. We found out what people did not know about mining. And, most importantly, facts they should know were singled out - facts that could create more favorable attitudes. This research was instrumental in the final direction of the Common Ground project. What the public believes As these perceptions about mining were researched, it was found that the beliefs of the general public are dominated by four concepts. Quotations from interviewees are included with the discussion of each of these concepts. Figure 1 shows an overview of people’s beliefs before education.

Jan 1, 1994

By G. Olson, T. Mudder, T. Clark

An evaluation was made of an innovative chemical approach for controlling the biotic portion of sulfide oxidation of tailing and waste rock using thiocyanate. This lipophilic anion is selectively toxic toward acidophilic bacteria, including those that oxidize metal sulfides. Sulfidic materials from precious metal and base metal mining operations were treated with thiocyanate solutions and subjected to accelerated laboratory weathering at 1 to 50 kg scale in humidity cells, trays, and columns. Initial field trials were conducted at 13.6 t and 100 t scale. Thiocyanate at relatively low concentrations reduced ARD from 50% to over 99%, depending on the sample and specific ARD parameter measured. Test work also was done with phosphate as an agent to coat reactive sulfides, further reducing their oxidation by biological and chemical reactions. The combination of phosphate and thiocyanate treatment is the basis for a potentially comprehensive approach to ARD prevention and control. Additional research and pilot testing are underway.

Jan 1, 2004

By Jaroslaw Drelich

This report briefly reviews the measurements and interpretation of adhesion forces measured between microscopic probes and substrates having micro- and nanoscaled roughness characteristics that were recently conducted at Michigan Tech using atomic force microscopy. The laboratory study concentrated on both rigid and deformable materials, with the probes larger than the size of roughness features of interacting surfaces. For such systems, a detailed surface characterization in terms of roughness parameters, asperity size and shape, and spacing between asperities, as well as analysis of deformation of materials is required. Analysis of the experimental data can be done with theoretical models, which are suitable for rough surfaces and therefore allows to normalize the measured forces. Alternatively, loading of the probe during adhesion force measurements can be managed properly to control deformations of the nano-scaled surface irregularities. Controlling the deformation reduces and even eliminates the effects of nano-roughness on the probesubstrate contact area, promoting conditions described by the contact mechanics models for the sphere-smooth substrate system.

Jan 1, 2005

By Robert L. Cascio

The mining industry uses a large amount of electric power. Their equipment is subject to extreme environmental conditions and mechanical shock. A significant number of electrical accidents are a result of improperly grounded electrical equipment. Federal regulations require the safety ground bed resistance to be measured once a year or after modifications. Most commercially available instruments used to measure the ground bed resistance require the ground conductor to be disconnected and the power system disconnected for safety reasons. The "fall of potential1&apos; method requires auxiliary ground rods and approximately two hours to complete the test. Although a new instrument was initially thought to measure the ground bed resistance immediately without isolating the ground bed, field tests have shown this method is not accurate. In some cases, a continuous measurement of the ground resistance is desired. A monitor has been developed and is presently being evaluated at several mines. These installations will be discussed.

Jan 1, 1992

By Bruce T. Stanley

Though most porphyry-molybdenum deposits lend themselves to various reserve estimating techniques, still there must exist the constant effort to not merely obtain an estimate but rather to obtain the best estimate. To answer the challenge of a complete ore reserve estimation, one must attack the problem with the purpose of obtaining the results closest to reality. What we wish to determine is simple: metric tons (short tons), grade, and kilograms (pounds) of molybdenum contained. In order to effectively accomplish this task, further consideration must be given to the ease of using the information obtained and its inherent reliability. The only known method for ore reserve estimation that supplies the needed results along with its distribution and a measure of confidence provided by sound mathematical backup is geostatistics. The following review is an example of geostatistical application of an ore reserve estimate at the AMAX Henderson mine demonstrating technique, viability, and usefulness of results.

Jan 1, 1979