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By Bruce Congleton

The Florida phosphate industry is a leader in environmental control, both in terms of dollars spent and significant achievements. For instance, since 1960 the phosphate industry has spent over $71 million for air pollution and control devices, including installation, research and development and maintenance. Water pollution control expenditures also total in the millions, with over $69 million spent in the same 10 year period. The industry also is a leader in water conservation measures, having spent nearly $ 18 million since 1966 for conservation devices. Since phosphate is mined by strip mining, land reclamation plays an important part in the environmental control picture. Here again, the phosphate industry has met the challenge with a voluntary program of reclamation which accounts for over 20,000 acres of land useable after mining has taken place. In terms of progress in environmental control, the industry has been able over the years to solve within the limits of technology the fluoride emission problems it once had, and is currently at work solving sulfur dioxide and particulate problems. In just the past year the industry also has been extremely successful in limiting phosphorus and nitrogen discharges into area streams. The industry continues to cooperate with state and local pollution control officials on matters of environmental control, and future plans include even closer cooperation and assistance, as well as increased expenditures.

Jan 1, 1972

This section is addressed to the computing needs of corporate (top) management which are less specialized than the computing needs of operating or divisional management described in the previous sections. It is essential that the computer be used as a tool to serve corporate management and that information and results are presented in a succinct form. A key responsibility of the manager of computer applications is to communicate well with corporate management. A common trap for computer management is to allow the development and implementation of sophisticated and academically interesting computer applications which do not enlighten corporate management in its decision-making task. Thus it is essential to devote sufficient time and effort to designing and specifying a computer system before developing and implementing the system.

Jan 1, 1979

By R. P. Moran, B. C. Lewis

The objective of this article is to discuss the fundamentals for determining the value of a limestone reserve or operation. The general step-by-step procedure, while prudent, is subject to the various site-specific issues that influence the valuation calculation. The most common methods for determining fair market value of mining lands are: comparable sales, operational analysis, and royalty analysis. An overview of typical eastern limestone mines (both quarries and underground) is presented. Specifically, properties in West Virginia and Alabama are reviewed and the sample methodologies and valuation calculations are presented.

Jan 1, 1991

By Adrian Smith, Debra W. Struhsacker

13.1 INTRODUCTION Cyanide is, a generic term indicating the presence of the cyanide ion (CN-). Cyanide is a very common, naturally occurring compound produced by many biochemical reactions. Many plant species synthesize organic compounds which contain cyanide in the form of cyanogenic glycosides (Knowles, 1976). For example, trace amounts of cyanide are present in the seeds and leaves of many members of the Rosaceae (rose) family (Kingsbury, 1964). Many common items such as lettuce, maize, sweet potatoes, kidney beans, (Oke, 1969) almonds, and cigarette smoke contain cyanide. As examples, a recent chemical analysis of chocolate-covered almonds measured a total cyanide content of about two ppm (Steffen Robertson and Kirsten, 1987); and the U.S. Surgeon General (U.S. Department of Health, 1964) has shown that cigarette smoke contains up to 1,600 ppm total cyanide. The chemistry of cyanide solutions is complicated because the cyanide ion forms compounds and complexes with many elements. Some cyanide species are highly toxic whereas others are relatively inert and harmless. Molecular hydrogen cyanide (HCN) is the most toxic form of cyanide. Under most conditions, HCN exists as a gas which readily dissipates or reacts with the environment to form less toxic or nontoxic forms of cyanide. Thus HCN is an ephemeral toxin, and many naturally occurring geochemical processes reduce the HCN concentration of a heap system with time. As discussed below, free cyanide includes the two species, ionic cyanide (CN-) and molecular hydrogen cyanide. Free-cyanide toxicity in man, mammal s, and aquatic species is we1 1 documented (Doudoroff, 1976; Ecological Analysts, 1979; Towill et al., 1978). The lethal doses reported for human adults vary with the type of exposure as follows: • One to three mg/kg body weight if ingested; • One hundred to 300 ppm if inhaled; and • One hundred mg/kg of body weight if absorbed. Acute toxicity of free cyanide to freshwater invertebrates ranges from 0.028 to 2.295 mg/l, depending on species and test conditions. Generally, free-cyanide concentrations greater than 0.1 mg/l are expected to kill sensitive species in freshwater or marine environments (Doudoroff, 1976;

Jan 1, 1988

By J-P Franzidis, M. C. Harris

Increasing costs, falling grades and a low gold price have caused severe problems for many of South Africa's gold mines. The need to maximise efficiency is extremely urgent. This paper describes the use of column flotation cell s to scavenge significant quantities of additional gold from flotation plant residues; in particular, very fine particles of free gold not recovered by conventional flotation. Experimental gold- specific collectors enhanced gold recovery significantly. The paper also reports the results of other plant trials, carried out on a variety of ores.

Jan 1, 1991

By C. L. McKenzie, R. A. Heig

The design and operation of metallurgical laboratories is discussed. Laboratory size, general laboratory equipment and metallurgical staffing are discussed from a standpoint of desired laboratory results.

Jan 1, 1986

By Richard H. Adams

INTRODUCTION With the discovery and depletion over the years of near surface ore bodies, exploration targets are tending to be at greater depth or overlain by various types of overburden which in some cases extends to considerable depth or is heavily water bearing. Access to these types of deposits for exploration and development often requires vertical shafts. This paper discusses the concept of small shaft engineering and construction, primarily for underground exploration but also for use as a low tonnage production facility or for mine ventilation. The option of a small shaft may be attractive in a number of cases, some of which are: The underground exploration of a deposit at depth where minimal expenditure is desirable until the potential of the deposit has been determined. The exploration shaft in many cases later serves as a ventilation way and second means of egress. Production of ore in a small tonnage/high-grade operation where decline access is impractical. For ventilation where other types of openings are impractical or would delay start-up of mine operations.

Jan 1, 1987

By P. J. Bethell

This paper reviews current fine coal cleaning circuitry, including water washing cyclones, tabling and froth flotation. It goes on to examine possible future beneficiation based on emerging technologies. Circuits considered include those incorporating spirals, fine heavy medium cycloning, hydrosizers and column flotation.

Jan 1, 1988

By Christopher J. Hall

This paper describes the results from computer runs simulating 24 different mine ventilation configurations with the main fan situated first at the top of the upcast shaft and then at the top of the downcast shaft. Real air was used, with evaporation, condensation and heat exchange. The results showed that power requirements for the forcing fan were up to 20% less than for the exhausting fan for equal mass flow rates.

Jan 1, 1989

By S. Veeramasuneni

The recent nonequilibrium electrophoretic mobility measurements by laser-Doppler electrophoresis coupled with the stability and prevalence of collector colloids in soluble-salt flotation systems suggest that the selective flotation of alkali halides is due to the adsorption of oppositely charged collector colloids by heterocoagulation. Previously reported flotation results confirm this surface charge/collector colloid adsorption model. These results also indicate that the sign of the surface charge has a significant effect on the extent of particle dispersion/aggregation. In this regard, the nature of such particle interaction forces at high ionic strengths are examined to improve our understanding of these systems. Atomic force microscopy (AFM) is now being used to directly measure the interaction forces responsible for the stability of these alkali halide aggregates observed in optical microscopy studies. Results from this study indicate that, while repulsive hydration forces exist between similarly charged hydrophilic particles, attractive forces exist between oppositely charged hydrophilic particles in high ionic strength solutions.

Jan 1, 1999

By William P. Shinn

The site of Pittsburg from the first knowledge by white men of its location has been regarded as a position of great strategic importance.

By Pedro Sanchez-Mejorada

Laguna del Rey is the name of a dry lake bed located in the State of Coahuila, Mexico in a semi-desertic terrain typical of the basin and range physiography. Química del Rey, S.A., a subsidiary of Industrias Peñoles, has been producing sodium sulphate since 20 years ago, from brines pumped from the sub-surface of the present playa. The spent brine is used as raw material for the production of magnesium oxide. An extensive, lenticular deposit is found just below the playa. It consists mostly of glauberite (sodium-calcium sulphate) and blöedite (sodium-magnesium sulphate). The glauberite occurs as thin crystals oriented at random and leave many void spaces among them. These intercrystalline spaces are partly filled with mud, but the whole mass of the evaporite is still very porous. A brine that contains in solution ions of sodium, magnesium, sulphate and chlorine occupies the voids of the sponge-like evaporite body.

Jan 1, 1984

By Gerald G. Griswold, Allan G. Provost

"To Sink or Not to Sink"; this play on the Bard's words sums up the considerations and problems that face the owner on every potential shaft sinking project. The growing demand for access into the earth is pressing construction into new areas and to greater depths. The following discussion will entertain some of the effects of these new and unknown aspects upon the approach to designing and sinking of deep shafts. We will also look at the current shortages of equipment, materials and skilled manpower, and their effect upon the planning and sinking of shafts. Particular emphasis will be placed upon equipment selection, and we will discuss how economics, while always a prime consideration, is now, more than ever, both an incentive and a detriment to the industry. FUTURE CONSIDERATIONS Shaft construction is assuming ever increasing importance both in mining and civil endeavors. The rapid depletion of near surface mineral reserves is requiring the mining industry to look deeper into the earth for new sources. These greater depths increase the exposure to unfavorable geological conditions; heavier ground, high water pressures, and high temperature. South African gold mines have now reached depths of 12, 000 feet, where the rock temperature is 1380 and water bursts from the fissures. In North America depths to 7, 500 feet have been sunk, but deep shafts are still generally considered to be those of

Jan 1, 1974

By Heinz Hofmann

In order to drive tunnels with low overburden in town regions, it is necessary to give a quantitative prognosis for the deformation of the underground as well as of the tunnel-lining and of its stability. These problems and their solutions are illustrated by the works for a two-track-railway-tunnel in Bochum (Ruhrdistrict). In this case the most important problems consisted in passing below buildings in a vertical distance to the fundamentals of only 3.20 m and a railway earthdam with rapid train traffic in a distance of 4 m under the dam. The results of measurements from other comparable tunnels and finite-element-computations were used to prognose the settlements on the surface and in the ground, their distributions and their development in time. To obtain these values at the site, a special system of tunnel driving was executed. The tunnel was excavated with the newest type of tunneling-machine from DEMAG, cutting an inclined front, immediately followed by a special temporary support of shotcrete and inclined steel-ribs. By using theoretical and empirical methods to assess the behavior of the tunnel and underground and by executing an optimal driving system in technical as well as economical aspects, the expected behavior, expressed in quantitative values, was almost equivalent to those received by control measurements.

Jan 1, 1974

By Victor Bush

Most governments recognize that energy efficiency represents a partial solution to reducing global capital shortages and environmental crises that threaten to seriously impede economic growth. Much of the United States and many foreign countries are embracing the concept of Strategic and Tactical Energy Planning (STEP) which incorporates Supply Side Management (SSM) and Demand Side Management (DSM). Since SSM comes at twice to three times the cost of DSM, it makes economic sense to employ the energy conservation techniques of DSM. This paper will explain these concepts, the effects of the energy industry restructuring, and risk management for the development of an overall strategic and tactical energy plan.

Jan 1, 1999

By James P. Dorian

Like Russia and Ukraine, Kazakhstan is one of a few former Soviet republics well-endowed in mineral and energy resources (Fig. 1). Kazakhstan is the second largest newly independent Commonwealth state. It possesses major fuel and power centers, including 20 electric power facilities that operate on the more than 300 kt (330,000 st) of coal extracted daily. These power stations supply Central Asia, the Urals and Western Siberia with much needed electricity. Kazakhstan plays a critical role in Central Asia as it serves as both the regions' economic and political hubs. While Kazakhstan already contains a robust and diversified minerals industry, the government is actively pursuing foreign investment to boost production capacity and improve efficiencies in operations. A primary objective of the Kazak government is the expansion of metal processing facilities to improve the country's long-term export potential. Since 1991, international mining companies have found the investment climate of Kazakhstan relatively favorable. This is due to tremendous efforts by government officials to create sufficient investment legislation and a national minerals policy, while eliminating bureaucratic bottlenecks common to most other former Soviet republics.

Jan 1, 1993

By M. Misra, J. Nanor

The removal and stability of arsenic over a wide pH range (3.0-10.0) from synthetic solutions and industrial waste effluents (including mining waste tailing slurry) can be accomplished with addition of impure lanthanum chloride alone or in conjunction with ferric sulfate. The long term stability of these correspond­ing precipitated compounds is critical from the disposal stand­point. In this paper test results of this new process for arsenic removal and stabilization from the above mentioned systems are presented. Also, precipitated arsenic compounds (lanthanum arsenate, lanthanum-ferric arsenate, ferric-lanthanum arsenate and ferric arsenate) from synthetic solutions have been charac­terized. The characterization technique used was XRD. XRD patterns which shows that the lanthanum arsenate and lan­thanum-ferric arsenate formed in acidic and alkaline pH at room temperature are crystalline. On the contrary, ferric arsenate and ferric-lanthanum arsenate compounds formed under the same conditions as lanthanum arsenate were amorphous.

Jan 1, 1998

By L. B. Paterson

Mining Engineers throughout the world have an appreciation for the importance of the role of the Blasthole Drill in one of the primary elements of the mining process. This paper highlights areas that could influence the overall cost effectiveness of that process of breaking rock and how equipment is designed and configured to meet that challenge. Factors influencing drill productivity and overall cost effectiveness are addressed, both in the Mine Environment and on the Blasthole Drill.

Jan 1, 1999

By M. Cimini

The main objective of this paper is to propose a new sustainability parameter, called Visibility Indicator (VI), to describe the influence of mining operations on the visibility of the open works in the site from the surrounding land. A further goal is to point out a procedure for Visual Impact Analysis and Assessment (VIAA) of mining and quarrying operations in the phases of elaborating and evaluating of the project and depleting the resources. The Visibility Indicator has been computed taking into consideration the evolution of the area involved in the exploitation activity.

Jan 1, 2003

Because of the different types of reagents used for the flotation of sulfide and nonsulfide minerals, it is convenient to consider these two groups of ores separately. The metal sulfides and native metals are substantially all floatable with xanthate and similar collectors.

Jan 4, 1982