Search Documents

By J. W. Sweeney

The .Florida land-pebble mining industry of central Florida was examined to identify trends in land use; conflicts in land use; and the effect of the conflicts on mineral resources. Many conflicts exist in the study area, such as conflicts with other users of land resources and land surface; conflicts with high revenue land users; conflicts for land surface in urban and suburban areas; and conflicting restrictions concerning utilization. Projections are made showing that lands in phosphate company ownership are expected to be made available to help meet the need for future urban expansion in the study area. Some phosphate resources have been lost due to land use conflicts, however, most of the resource loss has been small. Land use conflicts and phosphate mining are reconcilable and considerable progress toward their maximum and multiple use of land and mineral resources can be resolved through farsighted planning based on factual data.

Jan 1, 1972

By Andrew J. Neale, Mark Franklin, Mike Cooper

Although recent advances have significantly improved our understanding of flotation fundamentals, disturbance variables combine to make it difficult to maintain steady state operating conditions over either the short or long term. One of the major concerns relates to knowing how much reagent to add to the flotation system, how to monitor the addition rate, and how to determine when to adjust the reagent addition rate in the presence of these disturbances. This paper will look at the development and installation of process control systems that address these issues. The economic benefits that accrued from the implementation of these strategies is described.

Jan 1, 1994

By Y. J. Wang

The use of controlled recirculation began in the early 1930s. Although this method has been applied in many mines since then, a generalized comprehensive network analysis is still lacking. This paper presents a unique approach in which the ventilation network with a controlled district recirculation is divided into two subsystems: a main subsystem and a recirculation subsystem. The subsystems are analyzed individually, and the results and their relationships are then integrated into discussions of the total ventilation system. The analysis of the recirculation subsystem is facilitated by introducing a nondimensional parameter (A), which represents the ratio of the air quantity for the working face to that for the subsystem. As a result, far and regulator pressures and air power for various recirculation arrangements can be effectively expressed as a function of and the subsystem air quantity. Numerical examples are included.

Jan 1, 1997

By Scott K. Palm

The initial intent of the Hazard Communication Standard (HCS) was to improve worker health by providing more information about the hazards of chemicals used in the workplace. However, the impact of the HCS goes well beyond worker right-to-know. There are direct costs associated with compliance. In addition, labelling and hazard communications can provide a competitive advantage to producers of minerals that have not been identified as hazardous. Often, the lack of hazardous information about a substance is due to the lack of scientific study, rather than an indication of product safety. Currently, industry and regulators sometimes give known hazards greater weight than unknown risks.

Jan 1, 1991

By Heiskanen K., Koivistoinen P.

A common belief is that autogenous grinding suits itself only to certain oretypes. It is shown that properly designed autogenous grinding can be used even with very difficult ores with energy consumptions which are equal or lower than obtained with rod-ball mill grinding. The basic feature in the design is the large port grate developed by Outokumpu. The scale-up of the mills can be done on the basis of the base mill concept. It enables to compare different mill sizes and types. Simple scale-up equations are presented based on actual mill data and experimental work.

Jan 1, 1992

By S. Constantinescu

The alloys mainly used for short (or segmented) chip material cutting (cast iron, porcelain, etc) are alloys of the WC-Co type; in some cases with small additions of other carbons. The same alloys but of different granulometric classes are also used for pieces exposed to wear (wire drawing, moulds) The higher performance of the WC-Co alloys in chip machining applications is accounted for by their very good heat conductivity, which is 2-3 times higher than that of fast steels. The hard-alloys producers can resort to a wide range of possibilities to achieve variation of properties of a WC-Co composition and thus they can adapt their products to the particular type of tools they may choose to manufacture. The present metallography technique allows for a correct identification and evaluation of hard sintered carbons structures. The metallography approach is an indispensable method of investigation and control in the industry.

Jan 1, 2008

By J. J. Gusek, T. C. Richmond, R. W. Reisinger

A high-altitude (9,500-ft [2,900-m]) historic underground copper mine in Wyoming discharges neutral but copper-laden water into a pristine creek. Under a Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) deferral agreement, the Wyoming Abandoned Mine Land Program performed site characterization and treatment studies in preparation for reclamation of the site. An integral part of the project included addressing the needs of a variety of interested and affected parties, including property owners, local populations, government agencies, and the media. This paper discusses an overall approach and specific methods employed to enlist public support for the project as well as some of the successes and failures experienced.

Jan 1, 2004

By D. J. Dunn

Grinding balls, simple in shape, are actually sophisticated machine components and essential elements of mineral grinding mills. Their physical properties and quality must be adequate to achieve design life and grinding mission with few failures. Consistent properties and freedom from breakage are essential. Size, mass, hardness profile, chemistry, and microstructure are important variables that should be designed, specified, controlled, and verified to achieve optimal mill performance. Failure to specify ball properties in detail or failure to obtain required ball properties and quality can cause milling productivity losses and excessive costs that could endanger a milling operation's survival in the competitive mineral industry.

Jan 1, 1990

By Mehmet Maral

Various types of Tertiary (Miocene) lignite occurrences had been formed and alternated with volcano-sedimentary Bigadiç Formation in the field of study, which resides in the middle and eastern parts of Biga Peninsula. The focus of the study is to identify the geochemical and petrologic properties of coal occurrences and the formation mechanism of the deposits. A comparative study of the deposits will also be studied. Biga Peninsula is a very rich zone in terms of both metallic ores and industrial minerals. Most of the metallic deposits and industrial occurrences in the region have been known and mined throughout the history. This richness of the region is related to the volcanic and tectonic activities that have developed during different geological periods. These activities are the main reasons of weathering and alteration phenomenon.

Jan 1, 2005

By Don Minard

Management support systems are extremely important to mining management to enable them to operate their company as a business. Management must give attention to the financial, maintenance, materials, and other reporting and control systems that are necessary to successfully operate a mining company. This subsection describes the management support systems that are critical to most mining companies. In this introductory review, the major objectives and functions of these management support systems will be introduced. The following topics will expand on the functions and key concepts as well as other considerations in each of these systems areas. Additionally, this introductory review will touch upon the unique environment that mining companies find themselves in from a management and personnel standpoint and the effect of this environment on management systems. Additionally, specific keys to successful systems installations and acceptance in the mining industry are discussed.

Jan 1, 1979

By T. M. Ruff, W. G. McCoy, M. J. Beus, S. Iverson

Monitoring conveyance position and wire rope load directly from the skip or cage top offers several significant safety and production advantages. The Spokane Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH) developed a shaft conveyance monitoring system (SCMS). This system consists of position and guide-displacement sensors, a maintenance-free battery power supply and a new sensor, which is mounted on the wire rope with a Crosby Clip, to measure hoist-rope tension. A radio data link transmits sensor output to the hoistroom. A state-of-the-art automated hoisting test facility was also constructed to test the concept in a controlled laboratory setting. Field tests in full-size shafts are now underway.

Jan 1, 2000

By F. Leschhorn

A computer model for long-term production scheduling is presented. By combination of different operations research algorithms it has been possible to design a system which is able to solve difficult long-term planning problems. The practical application of the model by a west-german hard coal mine is shown. It is proven that the EDP-model provides substantial support to the planning engineer by solving complex optimization problems.

Jan 1, 1989

By D. L. Schweyer, W. A. Munson, R. H. Hanewald

Discussed is the INMETCO processing of electric arc furnace (EAF) baghouse dusts from the specialty-steel and low-alloy industries. In addition, the INMETCO process has been modified to recover nickel, chromium and iron from many other waste materials including: •pickling solutions or filter cakes, •spent nickel and chromium plating baths, •carbon refractories from pickling tanks, and •superalloy wastes including baghouse bags. INMETCO is the only North American company presently capable of recycling nickel-cadmium batteries by high-temperature metals recovery. This process and the details of INMETCO's best demonstrated available technology (BDAT) test program are discussed.

Jan 1, 1993

By K. S. Eric Forssberg, Lennart Ryk

The paper discusses coal utilisation in Sweden. All hard coals have to be imported from other countries. Peat from domestic sources is used as a complement. Environmental legislation and taxation on fuel and emissions are severe. This situation affects the procurement, preparation, handling and use of coal. The paper presents: • R&D projects concerning deep cleaning of thermal coal. • Handling and treatment of coal used in PFBC boilers and for blast furnace injection • Dust prevention for coal and peat briquettes. Procurement of coal emphasising quality and environmental issues.

Jan 1, 1995

By D. D. Lei, H. Sevim

In a recently developed, long-term open pit production planning model, the optimal plan is found by exhaustively searching through nested pits of maximum metal contents. A more efficient, dynamic programming (DP) based search algorithm now replaces the exhaustive search algorithm that requires prohibitively long execution time in real life cases. The logic and formulation of the newly developed search algorithm are illustrated through a small hypothetical case. An actual gold deposit is treated to demonstrate that the algorithm does indeed find the optimal production plan among all possible plans. A comparison, in terms of computational savings between the two algorithms, is also given.

Jan 1, 1995

By M. Amick, G. Swan, R. Hill, C. Pritchard

Falconbridge is a major basemetal producer in the Sudbury Basin of Ontario, Canada. The company identified a need to find a safe and cost-effective replacement for the welded wire mesh used to support loose ground during underground nickel mining. Falconbridge took a methodical approach to the concept of a spray-on liner as a screen replacement, proving the strength characteristics of the liner as a safe, cost effective and suitable method of supporting ground Compact, hydraulic mixing and spraying equipment were developed and are now in use at the Fraser Mine. Tekflex has been approved as a wire mesh replacement and has been in use since November 1998.

Jan 1, 2002

By Edgardo I. Cifuentes, Andrew L. Mular, Andrew Burkert

Experimental designs are data acquisition plans which, if followed exactly, will quickly provide process engineers with information to assess statistically the individual and joint influence of factors on responses to permit of rapid decision making. Methodology employed to construct data acquisition plans is described in some detail. In production environments, factorial designs are appropriate for most purposes. Use of two level factorials to make decisions is described for a grinding circuit.

Jan 1, 1991

By J. A. Herbst, A. E. Oblad, Y. C. Lo

The major cost in comminution is energy consumption, which can be as high as 50% of the operating cost. Improvements in plant operations have resulted in up to a 15% reduction in energy usage (kw-hr/t). These improvements have been made through the optimization of grinding efficiency and the use of expert model-based control systems. Optimization involves the determination of the levels of the critical-operating conditions that result in the most efficient breakage of ore in the mill. These optimal levels are identified through plant/laboratory test work and through computer simulation using advanced process models. Model-based expert control achieves the maximum performance from the grinding circuit by identifying the characteristics of the ore in the mill with an optimal on-line estimator. Using this information, the control system dynamically determines the operating point that will yield the optimal performance. Two industrial applications of grinding-circuit optimization and model-based control are presented to demonstrate the power of this new technology.

Jan 1, 1997

By Robin J. Batterham, Dave J. Robinson

The most significant trend in flotation has been the ever-increasing scale of operations. There is, however, doubt that this ongoing trend is enough to maintain the economics against trends such as falling grades, increasing mining costs, pressure on water supply and demand, rising energy demands needed for mineral processing, and a focus on whole of life value and mine legacy issues. We comment on the ramifications of broader uptake of more sustainable mining for mineral processing methods and address the specific question of whether recent progress in in-place recovery will lead to a timely breakthrough. The answer proposed is that this is possible in the next 10 to 20 years, but in the meantime the focus is just as likely to be on removal of waste (beneficiation) much earlier in circuits. Either way, mineral processing and flotation as we know it will change significantly. 

By R. F. Hüttl

World-wide Germany is the leading lignite mining nation. Most of the lignite is produced in opencast operations. However, opencast mining causes enormous impacts on natural ecosystems and even on entire landscapes. The extensive production of lignite particularly in eastern Germany results in large devastated areas, which so far have been reclaimed only to some part. For the restoration of the post-mining area of more than 80,000 ha the major land use option is the reestablishment of forest ecosystems. However, adverse site conditions of the post-mining landscape such as extreme soil acidification and salt concentrations call for specific recultivation practices. Therefore, after the German reunification new reclamation and reforestation concepts have been developed for these brown coal areas of eastern Germany by the Collaborative Research Center (SFB 565) at the Brandenburg University of Technology at Cottbus (Germany). As a case study our comprehensive investigations into forest ecosystem development on terra nova in the Lusatian lignite mining district, south-east of Berlin, will be presented.

Jan 1, 2003