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By Marion Loomis

Environmental regulation is an ever growing cost to the mining industry. Requirements for such items as air quality modeling, hazardous waste disposal, selenium concentration in water and sagebrush planting consume more of the mining industry’s resources each year. The mining industry is willing to make the necessary financial commitments to assure that the air, land and water resources are adequately protected and restored. However, it is sometimes difficult to explain to management and stockholders why money should be spent on a specific issue when science and common sense indicate it is being wasted. Common sense and sound science should dictate how mining is regulated.

Jan 1, 1994

By V. T. McLemore

In-situ leaching (ISL) operations have been proposed to recover uranium from sandstone-uranium deposits in NM. ISL (also known as in-situ recovery, solution mining, solution-leach mining, leach mining) consists of injecting a leaching solution into the mineralized zone through injection wells. The leach solution migrates through the formation, dissolves uranium and is recovered through production wells. The uranium is then precipitated through a conventional uranium recovery system. Several criteria must be met in order for in-situ leaching to be successful, most important is that the ore body must be amenable to chemical leaching. A number of ISL operations have been conducted in NM in the past (Mobil, Crownpoint; UNC-Teton, Section 23; Grace Nuclear, Hook?s Ranch, Seboyeta, Church Rock; Anaconda, Windwhip). Kerr-McGee (later Quivera Mining Co., Rio Algum) successfully produced uranium from mine-water recovery (recirculated mine water) from the Ambrosia Lake mines (mid-1960s to 2002). Despite some difficulties, ISL is a viable alternative to recovering uranium and could be utilized in the Grants district with proper aquifer characterization and monitoring.

Jan 1, 2009

By Allen W. Hatheway, John A. Albritton, Lloyd B. Underwood

Missouri River Division (FORD), U.S. Army Corps of Engineers (COE), has completed (October 1982) a study for the U.S. Air Force Ballistic Missile Office, in which desireable and needed changes in contracting methods for underground construction were identified. Due to the importance of geotechnical considerations in such construction, a good number of the resulting recommendations relate to geotechnical considerations. Corps contracts have traditionally served as models for contract documentation by public agencies and in private enterprise. Several standard features of present-day contracting methods were Corps innovations. Corps officials are generally in agreement with the recommendations of the Better Contracting reports published by the U.S. National Research Council (NAS/NRC), through its U.S. National Committee on Tunneling Technology (USNCTT). However, the findings of the 1982 MRD study indicate that additional changes are warranted for underground construction contracting methods; changes that deal specifically with site geological conditions, both known and to be reasonably anticipated, as well as with their associated impacts on construction. The 1982 MRD report identifies the need for nine specific improvements in geotechnical aspects of contracting; improvements based on recognition of geological conditions.

Jan 1, 1983

Waste areas of a mine should be sealed especially if there is a risk of spontaneous combustion. Leakage through and around such seals can be problematic. Pressure balancing has been one of the favored options to prevent the ingress of air into these waste areas. Balance chambers require maintenance and monitoring to ensure that they are effective. This paper explores the use of inert gas as a means of controlling ingress of air and egress of waste gases as a means of reducing leakage around seals.

Jan 1, 2009

By K. Park, J. Sohn

Recovery of industrially useful metals from various secondary sources is an important issue in Korea whose natural resources are limited and needs in the strategic metals are on the rise. In order to meet such needs, researchers at the Korea Institute of Geoscience and Mineral Resources have launched a number of projects to help the nation to recover various metals from secondary sources. In this study, silver is successfully recovered from spent silver-oxide batteries first by distillation to remove mercury. The distilled residue was next subjected to leaching of silver using nitric acid. The study involves finding optimum conditions to leach silver from the distilled residue and subsequently to recover silver from the leach liquor by chemical precipitation. The chemically precipitated products are then subjected to reduction roasting to recover silver metal.

Jan 1, 2002

By Satid Therdkiattikul, Donald A. Dahlstrom

By oxidizing the pyrite matrix through biological leaching of precious metals ores or concentrates, better than 90% recovery of gold and silver is achieved. The paper develops three precipitation processes that eliminates arsenic and all other toxic elements in the resulting liquor after the biological reactors. In addition, the precipitates are highly crystalline and resist resolubilization. The latter must be tested for at least six months by EPA test procedures. The three systems are temperature (must be at least 120°C or higher) lime or limestone. A continuous pilot plant was employed for all three systems and complete recommendations are given to optimize Fe/As molar ratio, reaction kinetics (detention time) pH, temperature, wt % feed solids as well as resultant reagent consumption based upon continuous operation.

Jan 1, 1995

By C. Strachan

This paper presents an evaluation of tailings dam incidents from the 1994 USCOLD Tailings Dam Committee report. Comparisons are also made with water storage dam incidents from USCOLD reports and recent tailings dam incidents. The evaluation results show that tailings dam incidents are due to a number of factors including overtopping, static and seismic instability, seepage and internal erosion, and foundation conditions, and that no particular type of tailings dam or operational condition is more susceptible to incidents. In addition, the results confirm that tailings dams should be located, designed, operated, and reclaimed with a thorough knowledge of site conditions, mill operation, site monitoring, and tailings characteristics.

Jan 1, 1999

By Donald W. Stever

In 1995 I was asked to participate in a litigation matter between a corporation and its insurance carriers concerning insurance coverage for remedial costs at a large, environmentally contaminated closed-down former industrial facility. One of the buildings on this site became known to the lawyers representing the company as “the infamous Building 8”. This building housed millions of documents retrieved from various locations at the facility while it was being shut down. It became apparent that the facility management had no document destruction policy, and thus Building 8 contained internal memoranda, notes, copies of correspondence, permits, operating records, inventory records, and the like from fifty years of operation. Needless to say, some of these documents, all of which were subject to discovery by the insurance companies in the litigation, contained material that was less than helpful to the company’s case. Of course, there were also a few helpful documents, but the overall usefulness of these records was outweighed by the negative impact they had on the conduct of the litigation. A second example involves e-mail. Several years ago, acting on an anonymous complaint that we later discovered was made by a disgruntled former employee who had been fired, a small army of federal environmental investigators descended on a client’s operating facility and, armed with a search warrant, literally commandeered the facility’s EH&S department. The investigators impounded the computers of the EH&S personnel and extracted all of the data from the hard drives of those PCs, as well as all EH&S related files from the hard drives of several servers used by the facility. These computers contained many years’ worth of stored e-mails, draft letters and memoranda, and other documents that provided grist for a four and one-half year criminal grand jury investigation of the facility and its EH&S staff. Both of these companies would have benefited from following a rigorous, enforceable, corporate records policy. Here is a third problem. My client had, during the 1960s, made a brief, and unprofitable foray into the nuclear fuel processing business. It ultimately sold the subsidiary, and was forced to give the purchasing company a broad indemnity against future liability. As might be expected, years later the facility was found to have considerable soil and ground water contamination both by chlorinated solvents and low-level radioactive material. Several years into the remediation program, my client discovered a tractor-trailer load of files, apparently removed from the subject facility, sitting in a parked trailer in a company-owned lot 300 miles away from the facility, where they had been for nearly thirty years. These documents were not helpful to the client, but had to be reviewed, at considerable cost, by paralegals. Moreover, several of the boxes turned out to have been mildly radioactive, setting off a chain of health and safety issues that consumed tens of thousands of dollars of legal expenses before they were resolved. Today, formal, enforceable corporate records management programs have become an extremely important element of overall corporate management. What was for most of the last century little more than a low level warehousing function is now a critical, actively managed, operating function that affects every level of corporate management. The rapid assimilation into corporate culture of electronic document management and the prevalence of e-email as the primary means of internal communication have created records management complexities the likes of which were not even conceived of fifteen years ago. Record preservation and destruction are no longer matters that can be handled on an ad-hoc decision making basis. Because of regulatory requirements affecting various classes of documents and the litigation consequences of ad hoc retention and destruction of corporate business records, and the need to have the ability to quickly retrieve documents in either a litigation or business negotiation context, a set of records management norms have evolved over time that have become the core elements of virtually every corporate records program. However, notwithstanding the existence of a set of norms (which are the basic elements of a

Jan 1, 2005

By K. Norrena

Grade control in open pit mining requires the specification of dig limits that account for mineral grades, economic costs, and selectivity of mining equipment. Visual identification of ore rock types is ideal, but this is not always possible in lower grade disseminated deposits where ore/waste contacts are not visually discernible. In this case, conventional grade control practice consists of a two-step procedure (1) create a map of mineral grades at some selective mining unit scale, and (2) determine practical ore-waste boundaries or dig limits on the basis of the gridded block grades or assay information. This procedure is laborious, depends on a subjective assessment of where the boundary should be, and may be economically sub-optimal. We pose the determination of dig limits as an optimization problem and solve that problem with the technique of simulated annealing. Simulated annealing has the unique advantage of being able to combine multiple non-linear constraints into a single objective function. We use maximum profitability and the ability of the equipment to mine the proposed dig limits as constraints in the determination of optimal dig limits. We require a map of expected profit for eah block. Geostatistical techniques are recommended, for mapping expected profit but not necessary. Geostatistics will provide a quantification of the uncertainty in the grades within rock types using all available blasthole samples and exploration drilling. Some variant of L-optimal estimation or kriging can be used to determine the block-by-block classification that is economically optimum. We also need the expected profit for each block. It is unrealistic to assume free selection, that is, each block cannot be extracted independently of its neighbors. The optimal balance of ''accepting dilution'' and ''wasting ore'' is achieved to maximize profit subject to equipment constraints.

Jan 1, 2001

By Y. A. Attia, M. Elzeky

Thiobacillus ferrooxidans bacteria were used in this work to study the effect of bacterial adaptation on the bioleaching of three iron-bearing sulfide minerals, namely, pyrite, chalcopyrite and arsenopyrite. The change in the pH during the bioleaching process was observed and the mechanism of the bacterial action were discussed. It was found that bacterial adaptation prior to bioleaching, enhanced the degree of sulfide leaching by 2-4 folds over that of non-adapted bacteria. A1 so the bacterial activity was enhanced by 2-4.8 folds. The pH of leaching solutions was decreased by the increase in both adaptation period and bioleaching time. It was also concluded that the mechanisms of bioleaching of iron-bearing sulfide minerals involved both the direct and indirect bacterial action simultaneously.

Jan 1, 1989

By R. Oler

The need for yieldable ground support, particularly in high stress or deep mining conditions, has grown in recent years. This paper highlights some of the current industry limitations and provides selection criteria for a new yielding ground support system, DSI?s Dynatork Bolt. This bolt distinguishes itself by withstanding 16 ? 30 kJ of energy deflecting loads anywhere from 7 ? 20 tons (depending on the energy). A summary of the laboratory test results and case studies will also be presented as a measure of the performance of this dynamic product.

Jan 1, 2012

By D. S. Saxena, Jack K. Tuttle

Lack of understanding of useful applications of explosives on construction work stem primarily from the fact that explosion is commonly associated with destruction. On rock excavation and other construction works a certain quantity of explosive is harnessed to perform useful work at the source e.g. blasts to disintegrate rock. Development in rock blasting techniques, including the use of multiple-row blasting with short delay ignition, have made it impossible to excavate rocks close to or below buildings even in closely built-up areas. To permit the use of explosives on construction projects, in ways that will not damage existing structures, guidelines have been developed from careful measurements of intensity of ground vibrations. Accurate electronic instruments are now available for doing this. PLANNING AND CONTROL Blasting operations must be carefully planned and carried out to avoid discomfort to persons or damage to property. This increase in the use of rock blasting in city areas alone has led to a number of problems due to ground vibrations, air shock waves, and the psychological effect of noise. While the latter seldom if ever causes damage, it does create irritation and discomfort to persons living or working near the blasting sites. A result of this is a steady increase in the number of complaints in respect of damage to houses and other premises. Many such complaints are genuine and damage may undoubtedly be caused when incorrect blasting techniques are used.

Jan 1, 1997

By R. Hipsley, D. Arbonies, P. J. Dobak, M. Visher

The Storm deposit is a high grade breccia hosted “Carlin-type” gold deposit located at the north end of the Carlin Trend. Storm consists of 3 smaller deposits: 1) 49er Zone, 2) End Zone, 3) Discovery Zone. Structural intersections and favorable stratigraphy at the Paleozoic Popovich/Rodeo Creek formation and Bootstrap limestone formation contact are the primary known controls to gold mineralization at Storm. High grade silica-sulfide breccia occurs in the footwall of the north-south trending, dike filled, Dee fault. This mineralization cross-cuts silicified heterolithic breccia zones localized above the Bootstrap limestone where northwest, dike filled, reverse faults cut this structural-stratigraphic horizon. 40Ar/39Ar dates of 37.57+ 0.34 Ma (basalt dike) and 162 Ma (lamprophyre dike) have been obtained from dikes in the Dee pit which are locally mineralized by the same event as Storm. This paper will focus on the descriptive aspects of the Storm deposits.

Jan 1, 2001

By Trevor R. Ellis

The extractive industries addition to the International Valuation Standards (IVS) is scheduled for publication in the next edition of the IVS book in January 2005. This will provide guidance for valuation of minerals and petroleum industry assets of all types for all appraisal uses. It will provide asset valuation support to the International Financial Reporting Standards for the stock markets of the world, and a global umbrella standard which can be supplemented for local needs by institutes and regulators. This paper discusses implementation of the IVS within the minerals industry and important issues that the industry should confront.

Jan 1, 2005

By A. A. Schweizer

This paper documents the growth and projects the future of Green Diamond Sand Products. Since1954, Green Diamond, located in Riddle, Oregon, has been producing sand from granulated nickel slag for use in various markets. Through the years, the company has seen several changes from its ownership to its product lines. In 1991, Green Diamond was producing abrasive sand at a rate of about 30,000 tons per year. It was at this time that Green Diamond became part of Glenbrook Nickel Company. Over the next eight years, Green Diamond would quadruple its production to over 140,000 tons while moving into three new markets, as well. Green Diamond is now producing sand for use in the abrasive, foundry, construction, and roofing industries. In 1998, Green Diamond again found itself under new, private ownership. With plans on developing agricultural sand and spent abrasives recycling, the future of Green Diamond appears to be one of further expansion coupled with diversification of its product lines.

Jan 1, 2000

By T. R. Ellis

Many appraisers/valuers believe that the only valuation method available within the Cost Approach category for Real Property appraisal is the depreciated replacement cost method. Some valuation and financial reporting standards setters also believe the same. This paper introduces the minerals appraiser to a number of useful methods for mineral property appraisal that are based primarily on the principle of contribution to value, the predominant economic principle in the cost approach. Most of these cost approach methods discussed are primarily for use in valuation of exploration tracts and resource properties that have no defined reserves. However, the powerful rural cost method can be used to calculate the contribution of categories of resources, reserves, and other property components to the value of a mineral property. This method can be applied to mineral properties at all stages of development, including producing properties.

Jan 1, 2011

By R. Snoby

Since its introduction in 2002, the modern air jig has processed a wide array of coals throughout the world. This paper explores the reasons and justifications for the installations and provides case history performance data. Specifically highlighted are air jig plants processing metallurgical coal in Colombia, bituminous coal in the United States and India and lignite in the United States and Spain. Each installation has unique reasons to justify an air jig facility. It is important to note that not all of the justifications were based on the ?most cost effective yield?, normally a mantra for coal preparation plant designers and owners. Dry jigging of coal has long been a proven technique for upgrading coal, the modern air jig, with its improved efficiency and operating systems simply extended the range of applications. In some cases, it even allows market quality coal to be produced when no other option is possible.

Jan 1, 2009

By F. B. Henderson

1.0 PROLOG Since the "end" of the Cold War, revolutionary new research and commercial remote sensing capabilities are being developed that will dramatically change the way we map the earth and address its environmental problems. The technology challenge is not the growth of new environmental remote sensing technologies themselves. It is, rather, how these new innovative observing systems can be accepted and used to the benefit of both the regulatory and the mining communities in the light of present concerns about unknown risks of discovery and liability. The basis for this paper is an unpublished technology primer prepared for the industry-government Workshop on Advanced Measurement and Site Characterization for Mining Impacts held at Colorado School of Mines, Golden, Colorado, July 14-17, 1997

Jan 1, 1999

By J. McMurray

Introduction Uranium was recovered from mining of collapse breccia pipe deposits in the Arizona Strip district in northwestern Arizona (Figure 1) intermittently between 1956 and 1990, with cumulative production having totaled 23.3 million pounds of U3O8 (8960 tU) at an average grade of 0.6% U3O8. Production was suspended in 1990 because of low uranium prices, but the recent resurgence in market price once again makes the breccia pipe deposits potentially attractive exploration and development targets. This paper describes: (1) formation of the pipe structures and their metallogenesis; (2) mining and milling of breccia ore; and (3) potential roadblocks to development of new breccia pipe mines. Breccia Pipe Formation Formation of the breccia pipes began in cave systems formed during development of karst topography in the Mississippian Redwall Limestone. The karst Redwall surface was eventually covered by up to 900 meters of shallow marine to continental sediments ranging in age from Pennsylvanian to Triassic. The pipes were formed by progressive upward stoping caused by groundwater ascending under hydraulic head along near-vertical faults, joints and fractures. The stoping process involved both chemical disaggregation and mechanical failure of roof and wall rock. Upward stoping of successively younger units allowed for upward propagation of a pipe and resulted in a chimney-like column of breccia between the steep walls of the pipe. Syndepositional thickening of sedimentary units of varying ages indicates that pipe formation began as early as early Pennsylvanian time and continued intermittently through Triassic time.

Jan 1, 2007

By Leonel Lopez

Throughout Mexican history, mining has been an important, traditional activity. Before the "Discovery of America," native miners worked a variety of deposits throughout the country, including Mixtec gold and gem mines in Oaxaca State and Aztec gold, silver and copper from mines in Michoacán. The 500th anniversary of Mining in Mexico after the "Discovery of America" was initiated by the Mexican mining sector on April 15, 1991. As early as 1548, when the Guanajuato mining district was discovered, Mexico had become a leading world producer of precious metals. Since then, Mexican mineral production has developed in cycles, responding to changing technological, economic and political conditions. During the 20th century, Mexican mine output reached its peak in the decades of the 1930s and 1940s, when it was producing about 40% of the world's silver, 15% of its lead, 10% of its zinc, 4% of its copper and 3.5% of its gold. In 1990, by way of contrast, these percentages of world output stood at 13.5% for silver, 4.7% for lead, 4.1% for zinc, 3.2% for copper, and 0.43% for gold. The lowest production levels were recorded during the 1960s and 1970s, when Mexicanization of the industry and increasing state controls weakened mineral economics to a point that mineral exploration budgets were sharply reduced or eliminated, along with the industry's future. Only the noble old mining districts continued to supply production, with occasional eruptions of "bonanzas" and new extensions in established mining districts.

Jan 1, 1994