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By Frank Ittner

In this section it is proposed to discuss operating methods considered good practice under the various field conditions commonly encountered. Efficient field direction and types of equipment needed to meet transportation problems are considered only to the extent that the desire to produce the best possible records must sometimes give way to the factor of cost. As in all engineering projects, alternative possible methods of operation must be considered in the light of relative costs as well as of the quality of results obtained, Cost may be in the background of much that is done in the field operations, but only the effect on record quality will be considered here. Record quality at a particular shot point may vary with the various factors of spread character (relative positions of geophones and shot point), shot-hole depth, formations opposite position of shot, size of charge, the effect of repeat shots, surface geology and culture in the immediate vicinity of the geophones, recorder instrument characteristics, particularly filter.

Jan 1, 1940

By Steven A. Bradbury

INTRODUCTION Passive dust control systems are quickly gaining acceptance in the bulk solids handling industries. The number of applications is increasing due to proven performance, especially in US power plants burning Powder River Basin coal. Air Control Sciences ®, Inc., of Boulder, Colorado, has over forty (40) patented Dustless Transfer ® systems in operation. All of the installations control workspace dust levels to less than 2.0 mg/m3, and in some applications reduced conveyor dusting by over ninety-eight percent (98%). Passive systems control fugitive dust emissions by minimizing the induced airflow in bulk material transfer and slowing its velocity. Traditionally, fugitive dust control in the mining industry was accomplished using either dust collection systems or dust suppression systems. The term passive dust control, indicates these methods don't use any active dust collection or suppression. Passive dust control systems are best suited to transfer from one conveyor to another. They can also be applied to transfers from feeder to conveyors.

Jan 1, 2004

By Clodualdo C. Conde

In order for Philippines Associated Smelting and Refining Corporation (PASAR) Corporation to remain a leader in the copper smelting and refining industry, continuous improvements in plant technology are required. Reliable performance of plant equipment is essential for a competitive smelting operation. PASAR is constantly searching for the best equipment and technology to allow us to manufacture products more efficiently. When the Smelter was commissioned in 1993, the Flash Furnace off-gas treatment system was a constant source of problems. There were frequent shut-downs of the electrostatic precipitator due to material buildups on the discharge electrodes and collecting plates. In 1998, the precipitator was successfully upgraded to eliminate the buildup problems and to increase the collection efficiency. The upgrade greatly reduced down time and maintenance, and the enhanced collection efficiency also eliminated pluggage problems and material losses in the Acid Plant. This extensive precipitator upgrade was accomplished during a 30-day Smelter turnaround.

Jan 1, 1999

A shortage of technical skills in all areas of the mining industry is being experienced worldwide. This has significant consequences for design, operations, productivity and safety and, therefore, needs to be seriously addressed, both in the short and longer term. It is therefore both a strategic and a tactical issue. Importantly, however, since mining is a long-term business, the shortage of skills must be dealt with from a strategic point of view to ensure the supply of the necessary skills for future mining. This paper will deal specifically with the provision of high level technical skills, that is, university graduates in mining engineering, and the outlook for the institutions that are currently producing such graduates.

Jan 1, 2009

By Linda C. Carrico

Those who manage the Nation's mineral resources rely upon a variety of organizations both public and private--to give them accurate mineral data, technical guidance, and expert advice. This directory provides a list of such organizations--a list that should prove a useful tool for those seeking mineral-related information and technical assistance. The directory lists Federal and State governmental agencies and national, regional, and State associations with activities in the mineral, metal, and material sectors of the economy. These organizations regulate mining, monitor mineral production, establish and enforce health and safety standards, identify and evaluate mineral resources, conduct scientific research, predict market trends, resolve environmental issues, and promote the interests of the mineral industry, its individual sectors, and its workers--to name a few of their functions. The listings in this directory--arranged by State--should help users who manage mineral resources identify agencies and organizations that can provide mineral-related information or technical assistance.

Jan 1, 1993

By M. J. Sapko

From 2001 to 2007, the Pittsburgh Research Laboratory (PRL) of the National Institute for Occupational Safety and Health (NIOSH) conducted studies to develop alternative methodologies to full-scale explosion testing for deter-mining the ultimate strength of mine seals. As a result, the PRL developed and proposes an alternative seal-strength evaluation method based on a hydrostatic pressure-loading concept. The researchers suggest pressure loading a seal using water to twice the expected dynamic design load. The hydrostatic chamber test offers a means of validating seal designs, establishing appropriate resistance functions and determining the ultimate strength of seals through testing to failure. This article contrasts the full-scale explosion and hydrostatic testing of mine seals using a simple dynamic system model and principles.

Jan 1, 2008

During the construction of storage caverns, and during their lifetime if the use to which they are put so requires, it is necessary to provide adequate ventilation to ensure the safety and comfort of the underground workforce. An analysis of likely contaminants during construction has indicated that where a large facility is situated in a rock mass of even moderate temperature climatic conditions are likely to be the limiting factor during most of the mining operation and atmospheric pollution when blasting is undertaken. Possible options for improvement are increased air flow, cooling of intake air and reduction of the heat source by altering the number and type of haulage units employed in the cavern. Local solutions are an alternative approach where heat problems are confined to a few specific locations

Aug 1, 1994

By M. A. El-Sohby

The paper describes some problems encountered with the foundation of a deep drainage caisson constructed on the Nile Bank in Cairo. The use of suction dredging while sinking the caisson led to a piping failure of the sandy soil in the base which was loosened during the process of pumping. A study was carried out to investigate the problem and a procedure was adopted to retain the stability of the caisson.

Jan 1, 2010

By Vincent A. Scovazzo

Many accepted and useful methods have been developed and used for pillar design. Each method has its own particular strengths and weaknesses. Three methods addressed in this paper are; empirical, analytical, and numerical. Each of these methods have their place in pillar design. Analytical methods result in close approximation of the ideal pillar (most economical, stable, or yielding) and are suitable for use in final mine design and in analyzing existing problems. BOYD uses the analytical method to develop site specific mine pillars design equations. An analytical method, one of many developed by BOYD, is presented here and is based on the procedure used by Wilson (1) and others in development of their empirical equations.

Jan 1, 1995

The purpose of this paper is to describe briefly the clean-up procedure adopted at the treatment plant of Paringa Mining & Exploration Co. Ltd. at Kalgoorlie, Western Australia.A clean-up is carried out at the end of each four-weekly period, and all figures subsequently quoted are taken from a summary of the results of the eight periods ending 8th April, 1941.STRAKING AND AMALGAMATIONOf the total gold won 22· 77 per cent. is recovered by straking and amalgamation.The discharges of both the primary and secondary ball mills are pumped over a common set of five ten feet long by three feet wide straking tables, set at an angle of 10 degrees, before passing to the 14 ft. diameter by 30 ft. by 8 ft. Dorr bowl classifier.This classifier is in closed circuit with both of the ball mills, hence the whole of the circulating load of the fine grinding circuit, which approximates to 800 per cent., is required to pass over the straking tables. For convenience in handling, corduroy cloths are used in lengths of 5 feet, and are picked up and replaced by clean cloths at four-hourly intervals. The avaHable straking area provided is, therefore, 900 square feet, or approximately 3·30 square feet per original ton per 24 hours. The density of the pulp passing over the tables is about 54 per cent. solids, the area provided per ton of pulp per 24 hours being approximately o· 2() square feet. Washing of the corduroy cloths is carried out on the day shift only, about 800 lb. of strake concentrate being obtained daily.This concentrate is sluiced from the washing trough on the elevated straking floor to the 4 ft. by 2 ft. diameter amalgamating barrel located in the gold room below.The barrel is of standard design and is rotated at 25 r.p.m. It is charged each day at 4 p.m., and grinding of the strake concentrate at approximately 70 per cent. solids is continued until 8 a.m. the following day. The barrel is then stopped, and the contents generously diluted with water, and after a few minutes rotation some of the slime is carefully poured off through the small discharge hole. This dilution and decantation is repeated until a good deal of the valueless slime has been removed.A further quantity of strake concentrate is then charged to the barrel, which is allowed a further 16 hours grinding period. After again diluting and decanting, approximately 25 lb. of mercury and 15 lb. of lime are added to the charge, which is then given an amalgamation period of 2 hours before cleaning up.By the process of grinding, diluting and removal of slime by decanting...

Jan 1, 1941

By Michael Altepeter

Big River Zinc Corporation, located in Sauget, Illinois, operates a neutral leach residue circuit. The residue produced in the circuit is sold to lead smelters for subsequent recovery of valuable metals. A research program was initiated several years ago to find a means of treating the residue at Big River Zinc to recover the valuable metals. The Ausmelt submerged lance reactor was selected as the best alternative for the first step of the process. Pilot scale tests were conducted at Ausmelt's facilities in Melbourne, Australia. Separations were excellent. 99%+ of the Zn, Pb, Cd, and Ag contained in the residue reported to the oxide fume. 99%+ of the SiO2,, Fe, Mg, and Ca in the residue reported to the slag which passed the EPA TCLP test. Subsequent leaching of the oxide fumes and purification of the leach solutions using conventional procedures produced solUtions suitable for zinc electrowinning and an upgraded lead sulfate cake for sale.

Jan 1, 1992

By Elaine Araújo

Since the ancient times, clays were used as decolorant material for various types of oils. These clays were called ?decolorant clay?. They have the property to decolor dye materials present in mineral oils, plants and animals. Biofuel is a fuel derived from biomass of live organisms. As biodiesel is produced from renewable sources, the generation of employment due to industrial scale production may cause a reduction in the dependence on foreign diesel importing, as well as the reduction of air pollution by the addition of biodiesel to diesel. This study aimed to develop a technological process to decolor post- consumption oil to be applied as biofuel. The results were characterized by techniques of XRD (X-ray diffraction), X-ray fluorescence and FTIR (Fourier Transform Infrared). It was observed that the post-consumption oils presented a higher decoloration result after treatment with the Brazilian clay.

Jan 1, 2009

By Juan Oswaldo Alfaro, Angel C. Nuñez, Hildebrando A. Cóndor

Se ha desarrollado un software para facilitar la evaluación del proceso molienda-clasificación en plantas concentradoras. Se ha modelado en UML-Lenguaje Unificado de Modelado; los datos e información se almacenó en SQL Server; se programó en Java (Programación Orientada a Objetos). Investigación Aplicada y Cuantitativa obteniendo como resultados un Software para Circuito de Molienda-Clasificación (Directa e Integral).

Sep 1, 2017

By M. Le Roux

Fine coal (-500 µm) is notoriously difficult to dewater. It is not uncommon for a dewatered product to have a moisture content as high as 30 per cent after vacuum filtration. This poses several handling and financial problems to such an extent that a lot of fine coal is discarded onto slurry waste ponds. A novel way of dewatering fine coal was developed at North-West University. It entails deliberately damaging the filter cake during dewatering to allow for an increased flow of air through the cake at the expense of the applied pressure differential. This method resulted in an average improvement in final cake moisture of between 3 per cent and 5 percent when executed in the laboratory under controlled conditions. A device was designed that could be fitted onto existing belt filters that would damage the filter cake as it passes by. This device was tested on a vacuum belt filter installation at a coal beneficiation operation in the Waterberg coal field in South Africa. The results showed a 3 per cent reduction in final moisture of the cake, proving the validity of the method at full industrial scale.

Jan 1, 2012

By Harry W. Campbell

A mineral survey conducted by the U.S. Bureau of Mines in 1983 identified no mineral resources in the Beaver Meadows, Blind Horse Creek, Chute Mountain, Deep Creek/Battle Creek, and North Fork of Sun River Wilderness Study Areas (WSA's). A prospect east of the Beaver Meadows WSA has low potential for lead resources. Sand, gravel, and limestone occurrences are numerous in the WSA's; however, similar or better quality materials outside the areas are abundant and more accessible to potential markets. Impure coal and titaniferous-magnetite occurrences are near the WSA's, but are not known to occur within these areas. In 1983, there were 7,025 acres leased for oil and gas within the five WSA's; no current mining claims were in or near any of the WSA's. Evidence of mining activity was found at only one prospect in the WSA's. It is inside the Deep Creek/Battle Creek WSA; no resources or resource potential were identified at this prospect.

Jan 1, 1984

By M. C. Chapman, P. L. Swanson, A. T. Iannacchione

The National Institute for Occupational Safety and Health (NIOSH) evaluated microseismic activity from three field sites to compare and contrast the characteristics of microseismic emissions from very different geologic, stress, and mining environments. Recently, NIOSH has embarked on a research program to evaluate the use of microseismic monitoring information to identify roof fall failure processes and to assess its potential to warn of unstable roof conditions. Large roof instabilities, such as roof falls and certain roof caving events, have proven difficult to anticipate representing an increased risk to miners working in these inherently hazardous areas. When local failure processes are better understood, appropriate control measures can be engineered to mitigate these hazards. This study used microseismic emissions to help identify three local rock failure processes. It was also shown that analysis of microseismic emissions can aid in assessing the degree of instability associated with these local rock failure processes.

By Charlie Adcock, Rob Farnfield, Andy Wetherelt

The ISEE Blasters Handbook gives guidance on the level of air overpressure likely to cause occasional window breakage (151dB) and general window breakage (171dB). A long-term safe level of 140dB is also suggested. This guidance is widely used by demolition and other contractors to assess damage zones in the region of explosive applications employing unconfined charges. Other reference material gives more detailed guidance relating to window area, aspect ratio and glass thickness. Despite the guidance given in these references, complaints by members of the public regarding window breakage continue to be received by explosives engineers from air overpressure levels well below the longterm safe limit. Such complaints are not limited to the use of unconfined charges but can even be generated from the highly confined use of explosives in quarry blasting. This paper describes a series of experiments with explosive charges fired in unconfined conditions close to various window configurations. The aim of the work was to test the existing guidance levels and to extend the knowledge base in this area. Topics covered include the role of differential pressure across windows in the walls of an enclosed space such as a room.

Jan 1, 2006

By Foster Fraas

One of the lithium minerals most widespread in the earth's surface is spodumene (Li2O-A1203-4Si02) a lithium aluminium silicate. For some time, deposits of this mineral were known to exist in the Black Rills of South Dakota, but it was only quite recently that Hess4/ pointed out the great magnitude of the low-grade e deposits it s in North Carolina. The theoretical lithia (Li20) content of spodumene is 8.04 percent. The only other minerals with such high lithia content are the phosphates, but these occur only in pockets and are not in extensive deposits5/. Actually, however, the lithia content in spodumene is never found to be this high, being nearly always below 7 percent for the pure mineral, and part of the lithia is apparently replaced by other alkalies.

Jan 1, 1937

By K. Thirumalai

The feasibility of breaking hard rock by thermal weakening and subsequent mechanical impacting was tested, Field tests at a basalt quarry in Dresser, Wis., demonstrated that large hard-rock blocks (5 by 5 by 5 ft) could be effectively reduced in size by this method. A series of secondary breakage tests, using air-propane heating, resulted in an average heating cost of $0.36 per ton. This combination energy approach provides an alternate means of size reduction of large hard-rock boulders for quarry and for underground are chute and grizzly operations where mechanical methods, used alone, are ineffective.

Jan 1, 1975

By M. Menéndez

Enhanced gravity separation appears to be one of the most promising methods for processing all types of <200-µm coal feeds and tailings. Systems based on this technology are reviewed, and the results of investigations based on C900 Multi-Gravity Separator tests conducted to assess the treatment of <200-µm, extremely difficult-to-wash coal settling pond tailings are presented. Multi-Gravity Separator processing tests of ultra-fine tailings with a high clay particle size content (22.6% <10 µm and 60.1% <40 µm) and a 69.56% ash content show that this material can be effectively treated after desliming (<10 µm) of clay-size particles to produce a coal with a 20.6% ash at a separator combustible material recovery of 69.3%. Desliming is shown to be critical in reducing coal ash content and combustible material recovery. Similar improvements are anticipated in the recovery and separation pro-cesses for other enhanced gravity separation systems from the desliming of feeds. Although not a conventional form of treating Multi-Gravity Separator data, the existence of well-defined polynomial relationships based on the product of drum shake amplitude and shake frequency relative to product coal recovery, product ash content and yields at varying wash water flows is demonstrated. Low-amplitude and intermediate- to high-frequency bed agitation are shown to produce optimum ash reduction results.

Jan 1, 2007