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The 1996 Arizona Conference was held in Tucson on Dec. 8 and 9. Attendance was 648, a 12% increase from the 1995 conference. The annual conference is organized by the Arizona Conference Board of Directors, representing SME sections from throughout Arizona and adjacent areas. In addition to those representing mining and processing operations in the Arizona region, the meeting was well attended by interested parties from throughout North America. These included vendors, consultants, academia, research organizations and corporate management. The technical program highlighted the meeting. It consisted of a keynote address and morning and afternoon technical sessions. In the technical sessions, 23 papers were presented by the mining, hydrometallurgical, smelting, geology and mineral-processing divisions. The conference was then capped by a banquet that included a talk by a noted economist. Keynote address The program was kicked off by a keynote address titled "Forecasting for the 105th Congress," by Rep. John Shadegg (R-AZ). He was elected to Arizona's Fourth Congressional District in 1994. Shadegg serves on the House Budget Committee, the Resources Committee and the watchdog Government Reform Committee. He stressed the familiar conservative positions of reducing government spending, balancing the budget and states rights. As a member of the House Resources Committee, Shadegg stated his support for the mining industry. Technical sessions Mining division. Two of the five presentations described developments at two Arizona mining operations. T.J. Swendseid of Phelps Dodge presented a paper titled "New developments at Morenci" and P. Garretson of BHP presented a paper titled "Startup of the Robinson Project." Morenci continues to expand its operation and recently broke records for production. Other developments at Morenci included the completion of a 600-m (2,000-ft) drainage tunnel and stockpile rehandling. In addition, Phelps Dodge moved Morenci's crusher plant. It was completely disassembled and reassembled in just eight days. Another interesting presentation was "Predictive maintenance techniques for large electric shovels at Cyprus Sierrita," presented by T. Ritzel of Cyprus Amax. The presentation described high-technology methods for predicting maintenance problems. These methods included vibration analysis, ultrasonic detection, infrared thermography, electrical measurements and tribology (the science of lubricant evaluation). The benefits of these techniques are reduced downtime of the equipment, as was demonstrated in case studies at the mine. The other presentations were "Introduction to NOSA 5-star safety program," by R. McKinnon, BHP Copper North America, and "A new design guideline for mine sealing," by K. Fuenkajorn, Rock Engineering International. Hydrometallurgical division. The hydrometallurgical session consisted of five papers. These included a presentation titled "Recovery of gold and silver using guanidine-based extractants," by M. Vining of Henkel Corp., Tucson, AZ. In this presentation, guanidine-based extractants LIX-79 and AURIX resin were introduced. LIX-79 was shown to have applications in copper-gold and high silver ores. In ammonia-cyanide leaching, AURIX was shown to be more selective in CIL vs. RIL comparisons. Other papers in the hydrometallurgical division included "Application of cobalt in the copper industry," by J. Hawke, OMG Apex Inc.; "Series parallel conversions and production gains at Cyprus Miami Mining's dump leach and solvent extraction operation," by E. Bilson of Cyprus Amax; "Lead alloy anode corrosion at the San Manuel SXEW tankhouse," by W .M. Gort of BHP Copper and "Hydrometallurgical treatment of copper refinery slimes," by B.C. Wesstrom of Phelps Dodge. Smelting division. Three papers were presented in the smelting division session. These included updates and reports on improvements at the Hayden, Hidalgo and BHP San Manuel smelters. For example, W.A. Dutton of Phelps Dodge presented "Recent improvements at the Hidalgo Smelter." These changes were aimed at reducing environmental emissions and increasing production. They included modifications to the fugitive-gas collection system to reduce particulate emissions, rubber lining the acid plant scrubbers to reduce corrosion and the installation of a cold lime softening system for water treatment. Equally interesting papers were presented by D. Norton of Asarco, Hayden, AZ, in a paper titled "Update of the Hayden smelter process," and by D. Jones of BHP Copper, San Manuel, AZ, in a paper titled "Update on first campaign of the BHP San Manuel Copper." Geology division. The session began with a paper that outlined the progress of an exploration project in South America. "The Pierina exploration project, Ancash Province, Peru" was presented by J.D. Lowell, Lowell Mineral Exploration, Rio Rico, AZ. Another paper was then presented on a copper deposit in Grant County, New Mexico. "Zonation of supergene copper minerals at Hanover Mountain, Grant

Jan 1, 1997

By David M. Parkes

The hydraulic movement of coal is here defined as the movement of all sizes of coal in pipes and open flumes, by gravity and against gravity. It is not restricted to coal which is in slurry form. In other words, it is not crushed to a size in the 8 to 20 mesh size range. The top size could be as high as 12 inches. The dewatering of coal which is transported hydraulically is carried out to restore the coal to a suitable form for further cleaning, or for transportation by other methods. The process involves complete separation of all the coal, wood and rock from the water so that the water can be recycled without undue damage to pumps, pipes and monitors.

Jan 1, 1976

By Jan M. Mutmansky

While production scheduling for both surface and underground mining operations is similar in nature, a rather large array of techniques is applied in solving such planning problems. The techniques consist of both rigid operations research (OR) methods and practical procedures which are not mathematically based. In the following sections, a short summary of some of the techniques that are applicable to production scheduling problems in mineral operations is presented. The techniques discussed are: linear programming, integer programming, dynamic programming, graph and network theory, simulation, and heuristic methods. For an in-depth comprehension of these techniques, the reader is referred to any of the available textbooks on these subjects. One or more references will be listed for each topic to provide a starting point.

Jan 1, 1979

By Joseph F. Shirley

Introduction Inorganic depressants are chemicals added to the froth flotation process to maintain or produce hydrophylic surfaces on one or more minerals so they will remain in the pulp rather than attach to the air bubbles. Whether a depressant will be effective in depressing a given mineral depends on how it is used and the environment in which it is used. Some depressants must be added and conditioned into the pulp before the collector is added. Other depressants can be added in the presence of previously added collectors and effectively depress the desired minerals. Often the concentration of depressant relative to the collector concentration is critical to making an economic separation. It should be noted that some depressants will only work when specific collectors have been used. Some reagents such as sulfuric acid and hydrogen peroxide essentially act as depressants by altering the previously added collectors so that they are no longer effective. Some depressants such as sodium ferrocyanide are only effective in a very limited pH range and an essentially collector free environment. Major Depressants CaO Milk of Lime is by far the most used depressant both in tonnage and dollar value. Although it is most commonly listed as a pH modifier, it is also an important depressant for pyrite in copper and copper molybdenite flotation plants. Although a simple pH adjustment will often depress pyrite, there are times when grinding with fresh milk of lime is required to obtain optimum depression. Lime is also a molybdenite and gold depressant. NaSH Sodium hydrosulfide is by far the most commonly used reagent to depress copper and iron sulfide minerals in by-product molybdenite flotation plants. NaSH also depresses gold, silver sulfides and silver chloride. ZnSO4 Zinc sulfate is commonly used to depress sphalerite in lead-zinc and copper-lead- zinc flotation plants. It has also been used to effectively depress talc in by-product molybdenite circuits at a pH of 6.5.

Jan 1, 1986

By F. L. Pirkle, D. A. Podmeyer

The mineral zircon is mined for use as specialty foundry sands, abrasives, ores of Zr02 and zirco¬nium metal, refractories and zirconium chemicals. It is produced as one of several products from heavy-mineral sand deposits associated with ancient shorelines. Because of its low coefficient of thermal expansion, its high melting point, its high refractive index and its chemical inertness, it is an attractive refractory material. Zircon varies from deposit to deposit in terms of grain size, grain shape and chemical purity. Thus, there is a wide range of commercial zircon products that differ in impurity levels, particle shapes and grain sizes.

Jan 1, 1993

By W. M. Pytel

A simplified two-dimensional model to analyze time-dependent load distribution and surface subsidence associated with longwall mining geometries is described. The model is based on the theory of beams resting on inelastic foundations and includes visco-elastic behavior of immediate floor strata, non-linear behavior of coal pillars, elastic behavior of face supports, and visco-elastic behavior of the overburden strata. The relative importance of the different variables affecting the performance of longwall mining geometries from ground control point of view is also analyzed. The model has been validated for field observations from one Illinois longwall mine.

Jan 1, 1986

By B. S. Treiber, R. A. Lohnes, S. M. Levorson

As part of a research program to develop a coal-handleability index that would predict the ease with which a coal would flow through a handling system, an apparatus was developed to directly measure the unconfined Yield strength and bulk density of consolidated-coal samples. The new test apparatus provides a fast and simple method for determining the strength and compressibility parameters that are associated with the handling characteristics of crushed coal. Comparative tests were conducted using a low-stress triaxial-test apparatus. To check the accuracy of the new method, four coals with a variety of moisture contents and gradations were tested using the new method. These tests indicate that the new test device yields valid results. Further, the speed and ease of operation of the new device makes it suitable for quality control and quality assurance in plants.

Jan 1, 1996

By John F. Bryce, Fazley A. Azhar

With increasing economic pressures to produce more with less, the material handling industry is turning to engineered solutions to reduce the number of people required to operate its facilities, monitor maintenance trends, pin point problems, increase throughput, decrease downtime, identify weak links in the production system, and increase times between scheduled maintenance. One solution to these problems is to implement a Total Control Solution (TCS) using industrial computers, fieldbus networks, and distributive Input/Output (I/O) for control, automation, data acquisition, and analysis. This paper will discuss some of the control fundamental principles used by Technisys, Inc. (TI) to implement TCS.

Jan 1, 1998

By M. Sagisaka

The purpose of this study is to obtain carbon dioxide emissions by copper production systems and quantitative merit to use copper scraps in Japan. Electrolytic copper and sulphuric acid originating from the refining gas are produced in the system. In this study, the inventories such as the fuel consumption of the unit processes and the in-house electricity generation were obtained from published papers and public statistical data. The following observations were made based on the Life Cycle Assessment (LCA) method: (1) Carbon dioxide emissions from the production of electrolytic copper and sulphuric acid in the system are about 1.0 kg and 0.4 kg/kg-product respectively. The carbon dioxide emissions attributable to the transportation of copper concentrate correspond to 20% of the total emission. This emission is higher than that of zinc because the metal content in the concentrate is lower than zinc. (2) The carbon dioxide emissions from the system decrease with the recycling of copper scrap to the converting process because the consumption of copper concentrate is reduced. The reduction is estimated to be 0.18 kg-CO2/kg-Cu at the point of 0.1 kg-scrap/kg-blister Cu. This corresponds to 9% reduction for the present system. However, this recycling leads to the decrease of sulphuric acid by 450x103 tonne at the point. The recycling of scrap should be evaluated not only from the reduction of carbon dioxide emissions, but also in terms of sulphuric acid demands as well as advantage of waste management.

Jan 1, 2003

By John M. Ackerman

INTRODUCTION In the spring of 1988 the Joint Venture of Freeport-McMoran Resource Partners, Limited Partnership, IMC Fertilizer Inc, and Homestake Mining Co. was awarded the sulphur lease for Main Pass Block 299, lease number OCS-G 9372. This was one of eleven leases awarded to the Joint Venturers. Following the initial discovery wells in December 1988, a program of delineation drilling confirmed proven sulphur reserves of 67 million long tons. Proven, recoverable oil and gas reserves are 39.4 million barrels and 7.2 billion cubic feet, respectively. Development of the sulphur mine was given approval as a fast-track project by the Joint Venturers in 1989. The oil and gas reserves were acquired from the original hydrocarbon lessee in 1990 and given fast- track status immediately. Fast-track for these projects meant design and engineering would not be complete before construction began JOINT VENTURE The Main Pass Joint Venture is one of thirteen joint ventures formed between Freeport and three other companies - IMC Fertilizer, Inc., Felmont Oil Corporation, a wholly owned subsidiary of Homestake Mining Co., and Texasgulf Minerals and Metals Co. Felmont has subsequently changed its name to Homestake Sulphur Co. and Texasgulf assigned their interests in the three leases they participated in to their parent company. Texasgulf did not participate in the Main Pass 299 joint venture. Joint venture negotiations, anticipating a lease sale in mid-1988, began in December of 1987. This Joint Venture was the first of its kind; created to acquire offshore leases, explore, develop and mine sulphur. The Minerals Management Service announced a lease sale date of February 24, 1988 on the first business day of 1988. This greatly accelerated the joint venture negotiations. Of the thirteen leases the Joint Ventures bid on, eleven were awarded. Freeport holds its interest in all the leases through its ownership interest in Freeport-McMoRan Resource Partners, Limited Partnership, and Resource Partners is the operator on all of the leases. The Main Pass joint venture percentage ownership is: 58.33 Freeport-McMoRan Resource Partners 25.00 IMC Fertilizer, Inc. 16.67 Homestake Sulphur Co. 100.00 The Main Pass Joint Venture paid $3,401,757 for the Main Pass lease and will pay a royalty of 12.5 percent of production value to the MMS . LOCATION The Main Pass mine complex is located in the Gulf of Mexico, in U. S. federal waters, about 27 kilometers (17 miles) east of Venice, Louisiana or 140 kilometers south east of New Orleans, Louisiana. It is situated in about 63 meters (210 feet) of water. HISTORY The Minerals Management Service (MMS) of the United States Department of the Interior administers the mineral properties of the United States located in federal waters. Periodically the MMS holds lease sales of blocks under its jurisdiction. Prior to the offshore discoveries of sulphur associated with salt domes leased for hydrocarbons, the MMS leased blocks with all minerals including hydrocarbons awarded to the successful bidder for the block. In 1963 MMS held the first lease sale of blocks specifically for sulphur. This sale was followed by a similar sale in

Jan 1, 1992

By B. E. Dindsale, P. B. Altringer, R. H. Lien

The Bureau cf Mines, U.S. Department of the Intericr, is investigating biolcgical and chemical deccntaminaticn of cyanide- containing leachates and residues. Biolcgical cyanide cxidaticn, using bacteria isolated from a precious metals tailings pond, destroyed >85 pct of the cyanide in several prccessing solutions containing up tc 280 ppm CN. Reaction time varied from about 4.5 hr in a trickling reactor using quartz as a bacterial substrate to 2 mo in unagitated, covered flasks. Chemical techniques were used to destroy the remaining complexed cyanide down to 1 ppm. Exploratory tests were also conducted using spent ore from heap leach operations as the bacterial substrate to determine if biological cyanide oxidation could be used to destroy the residual cyanide in spent heaps.

Jan 1, 1991

By W. C. Dailey

National Steel Pellet Co. operates eight 8.2-m diameter by 5.5-m long (87- x 18-ft) SAG mills to grind 15.24 Mt (15 million It) of taconite ore per year. Improvements to increase mill throughput, lower steel consumption, lower power consumption, and increase grinding efficiency will be discussed.

Jan 1, 1987

By Ugo Preti, Gianfranco Ferrara, Mark C. Williams, Thomas P. Meloy

Theoretical and experimental lockedness profile curves are the same when the model assumptions are met. They appear different because of the way the data is presented. Continuous theoretical lockedness profile curves present all the data, including the wings of the curves giving them the deep U-shaped configuration. Experimental lockedness profile curves, because of the measurement methods, are discretized, obscuring the wings. If the continuous theoretical curves are discretized, they are similar to the experimental curves. When a float sink test is used to measure an interval of locked particles, the integrated averaging of the separation process obscures the wings of the continuous theoretical curve. To disclose the wings with experimental data, narrow density or measurement intervals must be used.

Jan 1, 1992

By A. E. Isaacson, T. H. Jeffers

The U.S. Bureau of Mines (USBM) is investigating arsenic removal from dilute waters using a biological precipitation/chemical adsorption system. The method includes (1) inoculating water with ferrous salts to increase hydrogen sulfide generation by indigenous sulfate-reducing bacteria, (2) utilizing the hydrogen sulfide to precipitate the bulk of the arsenic as arsenic sulfide, and (3) using beads containing ferric oxyhydroxide to remove the remaining arsenic. This approach was applied to a contaminated water containing 13 mg/L As. Arsenic extractions up to 99% were achieved. The use of sulfate-reducing bacteria is particularly warranted in this situation since most of the required nutrients are present in the water. Based on successful initial efforts, planning is underway to conduct a pilot-scale test at the site.

Jan 1, 1995

By Long An, Chao Wu, Yuanhui Li, Xing Sun, Shuai Xu, Changyu Jin

Stage open stope mining (SOSM) maintains the stability of excavation openings by leaving a large number of rib pillars. Affected by the strong unloading due to stage mining and the low width-to-height (w/h) ratio of the pillars remaining, large-scale destabilization disasters of rib pillars or excavation openings easily occur when the distribution of ground stress or the size of rib pillars is unreasonable. In view of these problems, a physical SOSM model test was carried out based on an underground metal mine in the city of Chifeng in China, revealing the deformation and failure characteristics of the SOSM pillar group by overloading.

Jul 1, 2023

By J. L. Huiatt, D. G. Foot, J. D. McKay

The US Bureau of Mines compared column flotation using either fine or coarse bubbles with conventional flotation on a Montana chromite ore. On deslimed ore, fine-bubble column flotation produced a &.7% Cr2O3-grade rougher concentrate with 87% recovery, compared with 43.8% and 43.5% Cr2O3-grade rougher concentrates with 85% and 77% recovery for coarse-bubble column flotation and conventional flotation, respectively. On undeslimed ore, coarse- and fine-bubble column flotation produced rougher concentrates containing approximately 41.5% Cr2O3 with 95% recovery, exceeding conventional flotation, which produced 35.6% Cr2O3 -grade concentrates with 87% recovery.

Jan 1, 1987

By Robert McEwen

Conveyor equipment beyond its prime chronically suffers from a lack of understanding in today's plant environment regularly delivers more material than original designers ever expected. A case in point is a belt conveyor in a major hard rock mine/milling operation asking to bring the unit up to current standards while eliminating spillage and reducing airborne dust. The challenge was to keep the system going by revamping the system while keeping the same footprint and allowing for higher production rate. Thirty years of daily maintenance and dust collection costs have virtually disappeared by the end of this challenging upgrade.

Jan 1, 2008

By D. Hong, K. N. Han

The leaching behavior of rhenium in ammonium iodide solutions with iodine as oxidant was studied. Experiments were carried out in an autoclave to investigate the effects of stirring speed, temperature, solution pH, and iodine and iodide concentrations on the dissolution of rhenium. It was found that a high temperature and a high solution pH were essential for the efficient leaching of rhenium. The dissolution rate was found to be dependent upon the concentration of iodine and iodide. It was concluded that the dissolution of rhenium under the conditions studied was controlled by the mass transfer of iodine with an apparent activation energy of 15.8 kJ/mole.

Jan 1, 1999

By Stanley Kesler

The first of two initial 650-mw units of the Paradise Steam Station, located on the banks of the Green River in the south-central portion of the western Kentucky coal basin, is scheduled for operation in late fall of 1962. Location of the site is shown on the map of figure 1. This plant will be the eighth, large-capacity,, modern station built by TVA in a series starting with Johnsonville, operated first in 1951. During that period of 10 years,, unit sizes have increased from a capability of 125 mw to 500 mw at the recently completed Widows Creek Unit 7 addition and at Paradise to 650 mw. This new unit will take its place in a power system that serves an area of some 80,000; square miles with a present installed capacity of over 12,000 mw. Upon completion of the Paradise units and other additional hydro and steam units presently under construction, the system capacity will have reached over 15,000 mw. Projected load estimates indicate that this system will provide a margin' of slightly under 10 percent of dependable capacity above peak demand at that tire. One Paradise 650-mw unit at that time will represent approximately 4 percent of the total system installed capacity.

Jan 1, 1962

By G. Deschenes, P. J. H. Prud'homme

A laboratory study was carried out to evaluate the effect of oxygen and lead nitrate on the recovery of gold by cyanidation of a free milling gold ore, which contains 0.4 % copper as chalcopyrite. Efficient gold extraction is achieved only under specific conditions. The recovery of gold was increased from less than 90% to up to 98% by addition of lead nitrate. In the pre-leaching, the kinetics of oxidation of soluble sulphides are not an accurate indication for the length of the treatment. Even though the consumption of cyanide was reduced due to the inhibition of the dissolution of chalcopyrite by increasing additions of lead nitrate, cyanide consumption had to the held above 1.85 kg/t to maintain good recovery of gold. The continued addition of lead nitrate above 300 git had no impact on the recovery of gold. It was also found that the addition of lead nitrate at the start of cyanidation gave the same performance as when added during pre-leaching. The addition of oxygen increased the recovery of gold by 1.5%. The concentration ofNaCN had to be maintained in the range of700 mg/L because of the high concentration of copper in solution. The recovery of gold dropped significantly when the average NaCN concentration fell below 640 mg/L. Application of the findings of the laboratory study at the industrial scale led to improved plant performance.

Jan 1, 1997