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By Fredrick L. Johnson

In 1987, the U.S. Bureau of Mines began a study of the 4.0 million acre Toiyabe National Forest located in eastern California and western Nevada. This report is a compilation of published, company, and field data for part of the Paradise Range, Nevada. The information is intended to aid the U.S. Forest Service in their long range management of minerals and augment the USBM data base. The Paradise Range study area, located 60 air mi northwest of Tonopah, NV, encompasses about 100,000 acres of which approximately 71,000 are administered by the USFS. The area is in the Basin and Range Province and consists of an east tilted block of sedimentary, metamorphic, and volcanic rocks which have been intruded by granitic rocks. Three major mining districts, the Ellsworth, Gabbs, and Fairplay are in, or extend into the study area. The earliest recorded mining activity occurred in the Ellsworth district in the early 1860's. Commodities produced from the study area include gold, silver, copper, lead, zinc, mercury, tungsten, iron ore, magnesite, and brucite. The Phelps Stokes Iron mine has produced about 1.1 million tons of iron ore, the Baxter-Hancock mine has produced over 10,000 stu WO3, and the Gabbs Brucite-Magnesite mine has produced millions of tons of brucite and magnesite. Numerous other mines have produced, but quantities are relatively small. According to company information the Gabbs mine, currently producing, has brucite-magnesite reserves that will last at least 50 years at current mining rates. One hundred thirty one million tons of identified copper-molybdenum resources exist at the B.C. Springs prospect according to company information, but molybdic oxide (Mo03) prices would need to double or triple from the current $3.00-3.10 per lb before mining of the deposit would be economical. Most company exploration activity in the study area is now focussed on precious metals. Active, or recently active mining claims appear to cover more than one-half of the 100,000 acres studied.

Jan 1, 1991

By Edward L. McHugh

The appraisal of mineral resources of the Challis National Forest, Idaho, by the U.S. Bureau of Mines, was made so that the mineral resources of the forest could be appropiately considered in land use planning. Information from this study is intended to tip the U.S. Forest Service to incorporate mineral resource data into forest plans The study was done in conjunction with the U.S. Geological Survey, which released a companion report on the geology and mineral potential of the Challis National Forest in 1989. This summary report is derived from a more detailed USBM Open-File Report (MLA 6-91) that includes descriptions of mines and prospects, commodity profiles, and development cost models. Since the 1860's mines within the Challis National Forest have produced mineral commodities worth more than $590 million at current (1989) commodity prices. Identified mineral resources have a gross value of about $2 billion at current prices, including 8 strategic or critical minerals. The U.S. Bureau of Mines study identified and described 723 active and inactive mineral properties within the forest. Mineral properties with identified resources were evaluate to determine their economic significance, and an assessment was made of the feasibility of mineral development. Of the 2,516,191 acres in the Challis National Forest, about 390,000 acres were classified as having mining development interest. Commercially important mineral production, mainly of molybdenum, gold, and silver from the Challis National Forest is likely for the foreseeable future.

Jan 1, 1991

By Doss H. White

In 1989, Alabama's nonfuel mineral industry produced a State record of $463 million of nonfuel mineral commodities, an increase of $4 million over that reported by the State's mineral producers in 1988. The new record marked the fourth consecutive year in which mineral production increased over that of the previous year. Alabama ranked 22d among the States in total mineral value. Cement, stone, and sand and gravel were the three leading mineral commodities produced, accounting for 77% of Alabama's total mineral value. During the year, there were several acquisitions by Alabama cement and stone companies, and the only tantalum mine in the United States completed its first full year of operation.

Jan 1, 1991

This Bureau of Mines publication summarizes the industrial minerals industry of Idaho. It contains information on 119 principal deposits of 21 commodities in the State and describes the institutional and infrastructural factors affecting mineral development.

Jan 1, 1991

By J. E. Hamak

This publication contains analyses and related source data for 920 natural gas samples from 26 States and 2 foreign countries. All samples were obtained and analyzed as part of U.S. Bureau of Mines investigations of the occurrences of helium in natural gases of countries with free market economies. This survey has been conducted since 1917. The analyses published herein were made by mass spectrometer and chromatograph.

Jan 1, 1991

By Michael R. Norland

This U.S. Bureau of Mines report on U.S. and Canadian 1iterature pertaining to soil characterization and the use of soil amendments as a part of the reclamation process of coal surface-mined lands contains 1,280 references. The references were published during the 1977 to 1988 period. Each reference is evaluated by keywords, providing the reader with a means of rapidly sorting through the references to locate those articles with the coal mining region and subjects of interest. All references are annotated.

Jan 1, 1991

By Edward L. McHugh

The appraisal of mineral resources of the Challis National Forest, Idaho, by the U.S. Bureau of Mines, was made so that the mineral resources of the forest could be appropriately considered in land use planning. Information from this study is intended to help the U.S. Forest Service to incorporate mineral resource data into forest plans. The study was done in conjunction with the U.S. Geological Survey, which released a companion report on the geology and mineral potential of the Challis National Forest in 1989. Mineral development activity in and under the Challis National Forest has been of great economic significance to Idaho and the United States. Since the 1960's, mines within the forest have produced mineral commodities worth more than $590 million A current (1989) commodity prices. Identified mineral resources have a gross value of about $2 billion at current prices, including 8 strategic or critical minerals. The U.S. Bureau of Mines study identified and described 723 active and inactive mineral properties within the forest. Mineral properties with identified resources were evaluated to determine their economic significance, and an assessment was made of the feasibility of mineral development. Of the 2,516,191 acres in the Challis National Forest, about 390,000 acres were classified as having mining development interest commercially important mineral production, mainly of molybdenum, gold, and silver from the Challis National Forest is likely for the foreseeable future.

Jan 1, 1991

By H. P. Knudsen

In most open pit gold mines ore waste selection is based on estimates made from blasthole samples. These estimates frequently are biased. While it is true that high grades and "outliers" can induce a bias they may not be the only reason for the persistent bias seen at many mines. This paper focuses on a source of the conditional bias. In this paper it is shown that the poor blasthole sampling can cause a conditional bias in the estimates.

Jan 1, 1991

By Gordon T. Austin

The combined value of production of natural abrasives, which includes tripoli, special silica stone, garnet, staurolite, and emery, increased about 21070 in 1989. The increase in the value of staurolite and tripoli production was the result of an increase in the quantity of materials produced and an increase in the unit value. Emery decreased due to the significant decline in the volume of the material produced. Special silica stone experienced both a decrease in unit value and quantity produced. Garnet showed a small increase in quantity, but a decrease in unit value. The silicon carbide industry saw a slight decrease in the quantity produced and a 12070 increase in the value of production. The fused aluminum oxide industry showed a 5070 decline in the quantity produced, but enjoyed a 15070 increase in the value of production. Combined production for both industries decreased 4070 in quantity but increased 13070 in value compared with those of 1988.

Jan 1, 1991

By A. L. Mular, R. P. Edwards

"The operation of flotation circuits is often regarded as a combination of art and science. Expert systems offer a method by which the art may be captured and supervisory control of flotation circuits fully realized. Operating knowledge, the art, can be consistently employed to enhance regulatory control through the judicious application of an expert system. Using an expert system, a supervisory control routine was developed, and successfully implemented, in the copper flotation circuit at Brenda Mines Ltd.The expert system ran in conjunction with regulatory PI controllers on a personal computer. The expert system received assays via an on-stream analyzer and adjusted regulatory loop setpoints as required in real-time. From its commissioning in November 1989, to the end of the mine's operation in June, 1990, the ES was enthusiastically embraced by the operators and attained operating levels superior to those achievable manually.INTRODUCTIONExpert system (ES) software springs from research into artificial intelligence and is currently making significant inroads into business and industry. Proponents of ES's make many attractive claims; they are a means of capturing the knowledge of experts and they can be programmed by non-programmers. To date, most uses of this software in the process industry are in off-line applications, meaning that the applications are not tied directly to operating (on-line) environments. Moreover, in on-line environments, they are typically employed as advisors and only suggest changes. Human operators are required to close-the-loop to the process. Yet, ES's should be applicable to operating environments and, if the claims of the proponents are valid, should also be better than existing tools. As an intelligent controller an ES must use the knowledge of experienced operators, apply it directly to a process and do this without the intervention of human operators. On-line applications have been successfully employed in the closed loop control of SAG circuits (Herbst et al., 1989) and flotation circuits (Hales, 1989). Harris and Kosick (1988) detail an implementation for flotation control at the Polaris Mine."

Jan 1, 1991

By N. D. Jagger, I. M. Arbuthnot

The recovery and destruction of cyanide in gold tailings is currently a topic of great interest for both financial and environmental reasons. The environmental problem is particularly important in the U.S.A. at present with the environmental lobby waging a campaign to eliminate the problem of migratory birds dying after drinking tailings dam wate. Tough legislation with severe fines and jail sentences for company executives have been introduced in several states for exceeding cyanide limits. To reduce cyanide levels in tailings dams chemical treatment, including acidification, alkaline chlorination, the INCO sulphur dioxide oxidation process and the Degussa hydrogen peroxide process amongst others are being. used. In addition several processes are at various stages of development for the recovery of residual cyanide from gold tailings. Among these is the process developed by Cyprus Gold and pilot tested by DSIR Industrial Development. This process uses air to strip cyanide from the acidified barren pulp and will be used at Cyprus Gold Mines Golden Cross Mine on the Coromandel Peninsula in New Zealand (Fricker & OWers 1990).

Jan 1, 1991

By George Munro

New Zealand is a small, almost pristinely pure country environmentally speaking. It is blessed with an abundance of clear waterways, lush green vegetation and fresh clean air. It is a country in which agriculture and forestry predominate, and mining developments have to be introduced prepared to answer in considerable detail the question "How will this proposal affect the New Zealand environment as we know it today". Those who make the legislation have the difficult problem of establishing standards at a level which will maintain as far as possible the status quo without unduly inhibiting the developments currently approaching the starting line. We have been fortunate in some sense in that since the demise of the early gold rush days by the 1920's, little mineralisation of a complex nature has been uncovered in New Zealand. Coal fields have been developed in the central North Island, and on the West Coast and Southland regions of the South Island. A ban on large scale open cast mines in the Coromandel area has restricted mining in that highly prospective area, although three large gold prospects have got underway elsewhere in the last three years. There is no other ore processing being undertaken at present. Some recent proposals involving lead, gold and silver in complex arseno­ sulphides have failed to get the necessary approvals and have been discarded. Our ore processing problems are therefore straightforward ones, and confine themselves to acid drainage, mercury handling and disposal, and cyanide.

Jan 1, 1991

By R. Z. Pyrih

Pressure/ ,acuum lysimeters were used to instrument column tests containing several lifts of tailings slurry, and to sample pore water as the tailings lifts dried. The results of the column testwork demonstrated that air oxidation of sulfide minerals associated wilh the tailings residue neutralized the alkalinity of the tailings pore water. Neutralization of the alkaline pH volatilized cyanide which, in turn, destabilized copper-cyanide complexes and caused the precipitation of insoluble copper from solution. Analyses of pore water samples for microbial activity indicated high plate counts. The presence of viable microorganisms in the pore water implied that degradation of cyanide was enhanced by growth and activity of cyanide-consuming microorganisms in the tailings material.

Jan 1, 1991

By L. D. Jayaweera, R. G. Robins

The pocessing of gold bearing sulphide minerals wr ich contain arsenopyrite and other complex arsenic sulphide minerals results in arsenic containing emissions and effluents which must be given careful consideration in relation to clean air and clean water standards. The sources of arsenic and the various process options for treating arsenical gold ores and concentrates are briefly reviewed. The problem relating to the removal of arsenic from gaseous emissions from roasting processes is considered. Residues from aqueous processing contain a variety of arsenical materials which have not been characterised, and the long-term stability of these is suspect. 'rhe use of lime to stabilise aqueous residues as either calcium arsenate or calcium arsenite has been shown to be inadequate for long term disposal since both compounds are converted into calcium carbonate due to the influence of carbon dioxide in the atmosphere. Ferric ion solutions have been used to precipitate ferric arsenate or to form ferric hydroxide which binds the arsenic for short term disposal, The long term stability of these ferric materials is poor, but could lead to the acceptance of a slow release option rather than complete containment of residues.

Jan 1, 1991

By Alan G. Fricker

Cyprus Gold NZ Ltd will be recovering residual free cyanide in barren gold pulp by air stripping. Laboratory investigations by DSIR have indicated additional advantages by recovering the cyanide from pregnant pulp. These are a lower leach pH, a greater cyanide recovery and less carbon consumption. They have a net economic advantage of $1.20/tonne over recovery from barren pulp. The realisation of these advantages is dependent on three crucial technical aspects -optimum pH for dissolution, the absolute loss of cyanide and the stability of the aurocyanide ion. The laboratory investigations described herein address these aspects. Earlier work had indicated that the rate of dissolution of freely revolving gold discs at constant cyanide ion concentration increased with decreasing pH from 11 to 8. Attempts to repeat the work in a more controlled manner by measuring the corrosion potential and current density have, to date, not been reproducible, but do not contradict the earlier observations. Cyanide recoveries and balances were obtained on leaches at pH 10.5 and 9 at the same cyanide ion concentration -the lower pH requiring three times as much total cyanide. Unaccounted-for losses, unfortunately, exceed the accounted-for losses, making interpretation of the balances difficult. Nevertheless, it appears that the additional amount of cyanide at the lower pH of 9 may not be fully recoverable. It may not, however, prove necessary in practice to use more cyanide at a lower pH. Both the gold and silver cyanide complexes remain available for carbon adsorption, as do mercury, copper and iron. Zinc, and probably cadmium, nickel and lead, may precipitate during stripping, which is an environmental advantage.

Jan 1, 1991

By E. A. Devuyst, G. Robbins

A unique process for removing cyanide and base metal complexes from industrial waste streams was patented by G.J. Borberly et al. (1984). The process uses SO2 (liquid or gas, or solutions of sulfite salts, or from burning elemental sulfur), plus air that is dispersed in the effluent using a well agitated vessel. Acid produced in the oxidation reactions is neutralized with lime at a controlled pH generally in the range 7 to 10. The reaction requires the presence of soluble copper as a catalyst which can be supplemented by copper sulfate if necessary. The process can be applied to the detoxification of gold and silver mining waste streams, such as carbon-in-pulp (CIP) tailing pulps, barren solution bleeds, pond waters and heap leach rinse solutions and also to plating shops wastewaters. The SO.jAir process has substantial advantages over two of the main alternative methods of cyanide destruction, namely alkaline chlorination and hydrogen peroxide. Alkaline chlorination is highly penalized in terms of reagent consumption. Chlorine is a strong oxidant reacting with species other than cyanide present in the effluent such as thiocyanate and sulfides. Furthermore alkaline chlorination is an incomplete detoxification process. Iron cyanide is not removed and the potential for harmful by-products species exist. Consequently final effluents may be subject to additional treatment in order to comply with regulatory demands.

Jan 1, 1991

By A. Bruynesteyn

Most ores and coals contain sulphide minerals such as pyrite, FeS2, the sulphur portion of which is a ready substrate for a variety of sulphur oxidizing bacteria. Although there are several bacteria capable of oxidizing sulphide minerals, the most often discussed culprit is Thiobacillus ferrooxidans.. Oxygen from the air slowly oxidizes pyrite into sulphuric acid, but T- ferrooxidans can increase this reaction rate several 100,000 times.

Jan 1, 1991

By Stephen D. Hill, C. R. Ferguson, T. H. Jeffers, P. G. Bennett

The U.S. Bureau of Mines' Salt Lake City Research Center has developed porous polymeric beads containing immobilized non-living biological materials for extracting metal contaminants from waste waters. Immobilized biological materials include peat moss, algae, biological polymers, and other materials that demonstrate high affinities for heavy metals. The beads, designated as BIO-FIX beads, have distinct advantages over traditional methods of utilizing biological materials in that they have excellent handling characteristics and can be used in conventional processing equipment or low-maintenance systems. Toxic metals such as copper, cadmium, zinc, lead, and mercury are several of the many heavy metals effectively removed from mine waste waters using BIO-FIX beads, Continuous cyclic testing indicated that the beads continued to produce treated effluents which met National Drinking Water Standards (NOWS) after 150 loading-elution cycles. Adsorbed metals were removed from the beads using dilute mineral acids. In many cases, the extracted metals were further concentrated to enable processors to reclaim the metals, thus minimizing the generation of a hazardous sludge, Tests indicated that use of the beads in a low­maintenance system was particularly effective for treating remote acid mine drainage waters and small toxic seeps from hard-rock mining districts.

Jan 1, 1991

By Chris Joyce, Peter Ryan, Graeme Mcllveen

This paper briefly summarizes regulatory procedures and government agency roles and jurisdictions in each Australian State and Territory. The role of the Commonwealth of Australia and selected current trends in environmental regulation are also discussed. While the Commonwealth has played an active role in regulating specific commodities or mines through its powers over export licences, international heritage agreements and the Territories, such cases have largely been a result of response to specific public issues. This may change; the Commonwealth has established the Resources Assessment Commission and is canvassing the establishment of an Environmental Protection Act, aimed at the standardization of environmental standards through the creation of an Environmental Protection Authority. While the States, the Northern Territory and the Commonwealth lwve nominally different resource planning, environmental project approval and operational regulatory authoritit:s, the fundamental principles hinge on mining lease, planning and pollution control approvals.

Jan 1, 1991

By Martin F. Grier, Nicholas H. Kempton

The Mt. Todd Gold Project in the Northern Territory is a joint venture between Billiton Australia Gold Pty. Limited, a wholly owned subsidiary of Shell Australia Limited, and Zapopan NL. As manager of the project, Billiton is guided by Shell's corporate policy that foremost consideration be given to protection of the environment from unacceptable impact and that sound environmental programmes are to be implemented effectively at all company operations. This policy on Health, Safety and the Environment helps operating companies in addressing environmental matters in a systematic way and gives guidance on the practical implementation of a range of controls to protect the environment. Most importantly, it seeks to do this in a co­ operative rather than adversarial manner. In developing the Mt. Todd Gold mine the joint venturers' environmental objectives have therefore been to plan and operate the project consistent with the highest industry standards and community expectations and in accordance with all Northern Territory government requirements. A development strategy has been designed which minimises environmental effects. Planning priorities have focused on the successful co-existence of the mine with an endangered species of bird, the Gouldian Finch, which breeds in the area; the mitigation of impacts on surface and ground. water qualities; and the protection of significant Aboriginal cultural and archaeological sites.

Jan 1, 1991