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By Numan Elmas

Barite deposits located in Dinek and surrounding region have important economic features with their large reserve capacity for Turkey. The objective of this study is to elucidate geological and depositional characteristics in terms of. site investigation and chemical analysis. In order to do this, geological area of about 300 km2 was examined and detailed geological map was constructed. It was observed that Barite mineralization in these deposits was occurred in carbonate and pelitic rocks of Lower Cambrian-Lower Ordovician. Deposits were exposed to advanced diagenesis regional metamorphism and tectonics that rotated and deformed the barites; therefore, barites shows secondary veins, brecciate and fracturing structure. Even though, a few light isotope values of barites may suggest hydrothermal and exhalative sedimentary characteristics or possible mixing with magmatic fluids, generally heavy isotope values indicate that the sulfate ions were supplied from coeval seawater and, many of sedimentary features and petrological, geochemical characters support dominantly sedimentary origin.

Jan 1, 2005

By Edward Burris, Terry Gorsuch, Joseph M. Hans

INTRODUCTION In any large earth-moving operation, good planning and management are necessary to complete the operational tasks promptly and successfully. When an earth moving operation is complicated by radioactive contaminants, normal earth moving techniques and procedures must be modified. Any planning and management, therefore, must include the radiological aspects of the operation. It was found that the radiological aspects dominated most of the planning and management activities and were extended to all facets of the decontamination work at the former Shiprock uranium millsite. These planning aspects are discussed and their use to develop a work plan is described. The management aspects are discussed and their use to establish a management structure are also presented. PLANNING Some method of procedure, formulated beforehand, was necessary to govern the decontamination work at the former Shiprock uranium millsite. This procedure was expressed in the form of a work plan which served several listed purposes. 1. It defined the work to be done and the sequence it would follow. 2. It was used as a yardstick to measure progress. 3. It was used to assign organizational responsibilities. Several factors were considered to aid in the development of the plan. These factors are discussed below: Goals It was established that radiation exposure was occurring to persons working at the millsite, and in an around the community of Shiprock, from airborne radioactive mill wastes and radon-222 exhaling from the tailings piles. The goal set for the decontamination work was to reduce on-site exposures to levels acceptable for the millsite occupants. The attainment of this goal would also have a substantial impact in reducing off-site exposures. The objectives necessary to achieve the goal were consolidation and containment of the wastes. The former objective implies decontamination of the millsite and environs, and the later implies stabilization of the wastes. In practice, a total and complete decontamination of the millsite and contaminated environs would be very difficult and costly. The costs for decontaminating them could be high enough that an alternative method might be more cost-effective for reducing human exposures (i.e, move the affected people away from the source). The interim guide "Radiological Criteria for the Decontamination of Inactive Uranium Millsites" was used for the decontamination criteria (EPA 74). Briefly, the criteria state that off-pile decontamination should be effective enough to reduce the net above ground exposure rate to less than 10 [u]R/hr for unrestricted use of the affected area. When decontamination cannot readily be achieved, the exposure rate levels could be relaxed to 40 [u]R/hr; however, the affected area has to be restricted. The second objective, waste containment, means isolating the wastes from the biosphere. Since no method of containment was available at the beginning of the millsite decontamination effort, temporary containment (interim stabilzation) became the objective. The tailings pile and decontamination wastes would be covered with clean fill. The interim stabilization should last from 5 to 10 years until the final disposition of the wastes will occur. The goal, therefore, would be achieved by decontaminating the off-pile areas to less than 10 uR/hr where practical. The decontamination wastes would be used to plate the surface of the tailings pile and would be covered with clean fill. Radiological Survey The radiologial survey is the key factor for planning a decontamination activity. The survey should delineate the spread and depth of the contaminants relative to the decontamination criteria. Surface wastes, in general, can be evaluated for spread and depth with reasonable radiation survey equipment. Subsurface wastes on the other hand can be missed entirely, as happened during the radiation survey at the Shiprock site, although numerous exploration holes were bored and dug. The survey results can be used to define areas that may not be amenable to decontamination because of complications or safety reasons. For example, no decontamination of the bluff base was to be attempted because of the possibility the bluff might collapse on the personnel and equipment. Contaminated bottoms of decant ponds on the flood plain were not removed because they would be slurried by ground water. Slurry removal was deemed inefficient because the contaminants would be scattered and no equipment was available for its transport. In summary, the radiological survey defines the boundaries of the decontamination work and provides

Jan 1, 1981

By Biswajit Samanta, Pranjal Pathak

This article presents a customized genetic algorithms (GA) with new crossover and mutation operators to solve the short-term production scheduling problem of multi-mine mineral value chains (MVC). The preceding problem consists of determining the extraction sequence and destination allocation of blocks from all the mines collaboratively while closely meeting the quality and quantity requirements of the processing units subject to relevant technical and operational constraints. The short-term production scheduling is carried out at shorter scales wherein the operations are modeled in a great detail with large number of constraints. This makes the industry-scale instances of the problem computationally intractable for standard mixed-integer programming (MIP) solvers. Thus, a GA-based heuristic approach is developed to obtain nearoptimal solutions to the large-scale instances of the problem in a reasonable amount of computational time. Computational experiments show that the developed GA-based method is a promising way to handle industry-scale instances of the problem. Moreover, the sensitivity analysis on various parameter combinations of crossover and mutation operators indicates that the customized global mutation operator, when used in combination with the customized crossover operators, took on average 12.5% less time than the customized local mutation operator to converge to a solution.

May 21, 2022

By Michael E. Kelahan, Glenn A. Gruber

A review of recent phosphate beneficiation developments shows that Flotaire cells, ranging from 0.20 m to 2.44 m in diameter, have been examined in pilot scale and commercial plants. Applications of the column cells have included sized feed fractions using anionic and cationic reagent systems. In plants where the Flotaire was installed as a test unit or as an optional circuit, its use has been largely discontinued. On the other hand, when management committed to installing the Flotaire as an integral part of the flowsheet, the performance expectations were met or exceeded.

Jan 1, 1988

By H. Shafick Hanna

The beneficiation characteristics of low grade Birmingham red iron ores of the Big Seam and Ferruginous Sandstone seams were investigated using flotation and magnetic separation after reduction roasting. Samples of Bib Seam Ore responded more readily to concentration than the Ferruginous Sandstone ores. The impurities inherent with the iron oxide minerals limit the grade of concentrates recoverable from these ores to a maximum of about 61% Fe if reasonable iron recoveries are sought. Flotation concentrates assaying 60-61% Fe and about 0.1% P with attendant iron recoveries of about 63% were achieved from Big Seam ore charges while those obtained from the low phosphorus Ferruginous Sandstone samples analyzed 54-56% Fe. Reductive roasting and magnetic separation of ground charges of the two ore samples yielded concentrates assaying 60-61% Fe. Iron recoveries were better than those achieved by flotation, but the magnetic products of Big Seam ore were high in phosphorus (0.2-0.3% P).

Jan 1, 1983

By R. S. Olsen

Intensely altered rock has had a large effect on slope stability as slopes increase in height at Island Copper mine. Traditionally used, fracture-controlled rock slope stability design techniques have been supplemented with analyses of failure modes which include failure along curved surfaces typical of soil materials. A rock mass rating (Pa) system has been developed that addresses the lower end of rock mass strengths. Rock masses are rated in terms of fabric integrity, alteration, fracturing intensity and gouge strength. Rock mass classes have been defined using statistical frequency distributions of rock mass rating values. Strength values have been assigned to the various classes from shear testing, back analyses of failures and engineering judgment.

Jan 1, 1987

By Chen Bing Ching

Hsikwangshan mine is located at Lengshuijiang city of Hunan Province. It is a stibnite deposit. The orebody is gently inclined; its ore run is about 3 km in length and extends about 1.2 km along the direction of dip. The thickness of the ore body is non-uniform and varies from 1.5 to 20 m. The orebody is mined by room and pillar and cementation filling. The nine levels at the ore top have been mined out. At present, the mining operations are at the eleventh level. The mine ventilation system consist of three main fans which are installed in different shafts and are ventilated in parallel. The main fans can be connected to each other through comprehensive return air drifts. Two of the fans are located underground and the other on the surface. The general configuration of the ventilation system is shown in Figure 1. Because the operating areas are scattered and vary frequently as well, it is difficult to bring about air flow control. If the air flow cannot be varied with the variation of production in time, the air quantities are not sufficient in some areas and are excessive in others. However, it is also a problem to coordinate the three main fans with one another to obtain the optimum economic cost of operation. In order to make the air delivery fit the variation of production continuously to satisfy the ventilation requirement of the working faces and to reduce power consumption, we have made a great effort over five years to install an automatic control system for mine ventilation at the Hsikawangshan mine. The key part of this system is a microcomputer. The whole system consists of a console, which is located at the surface; the circuit network that is provided for signal transmission; air doors and ventilators at the working face; the scale air doors which are installed at the main branch airways; main fans and their speed regulating devices, as well as the sensors used for observing pressure, air quantities, temperature and the concentration of carbon monoxide, etc. This system can continuously telemeter the air quantities and carbon monoxide concentration in the main branch airways, air pressure, air quantities, electric current, the temperature of the bearings of the main fans, etc. According to the production air requirements, the system controls the ventilators or air doors which are located at the working faces and regulates the air quantity in the main branch airways. It can also choose the optimum mode of operation automatically, and regulate the rotating speed of the main fans to guarantee the least total power consumption while satisfying the total air quantity requirements. If abnormality of the observed results is discovered, the audible and flashing light alarm signal starts up automatically. The operating mode of ventilation equipment also feeds back to the control room and displays on the console. The configuration of control the system is shown in Figure 2.

Jan 1, 1987

By G. Hargrave, K. W. Moloney, M. R. Stokes

In recent years drivage advance rates in the UK have in- creased from 35m per week in the 1980's to 100/150m per week possible today. These extended rates of advance have resulted in an increase in the potential methane, dust and heat generation at the drivage face. In order to disperse this additional pollutant load requires an increase of fresh air at the face. Although advance rates have changed, current auxiliary ventilation practice has not. UK mining law requires that the fresh air must be delivered to within 5m of the face. This has lead to the wide spread use of overlap auxiliary systems, since a pure forcing system set at this distance would lead to excessive airborne dust. UK mining law does not at present consider on-board mounted exhaust scrubber fans to constitute an effective overlap fan within mechanised drivages. In an attempt to determine whether working conditions could be safely and economically improved within mechanised drivages, a series of preliminary full scale gallery trials were con- ducted. A summary of the principal findings of these trials are presented together with an outline of a series of representative CFD simulations, scale model experiments.

Jan 1, 1997

By Peter S. Schneidkraut

This paper will discuss the Final Tunnel Linings which were placed in 6700m of a 2.32m inside diameter precast concrete lined interceptor sewer tunnel in Staten Island, New York. Two methods were employed to install the final tunnel linings. One method involved forming and placing a polypropylene fiber reinforced concrete cunnette invert, followed by an arch pour. The second method involved the jacking of reinforced concrete pipe into the tunnel, followed by a low density cellular concrete backfill grout. These two methods will be described and compared.

Jan 1, 1993

By G. A. Parkison

The sequential copper analysis method is a particularly useful technique to semi-quantitatively define the geologic, mineralogic, and metallurgical types and zonations commonly associated with porphyry-type copper deposits. The method is based on the partial dissolution behavior displayed by the prevalent copper minerals malachite, chrysocolla, chalcocite, and chalcopyrite to solutions containing sulfuric acid and sodium cyanide. Results from sequential analyses of the sample and analytical residue using sulfuric acid followed by sodium cyanide and then aqua regia solutions when compared with conventional total copper analyses can determine the amounts of leachable oxide minerals, leachable secondary sulfide minerals, and primary copper minerals, respectively. Sequential assay analytical results and interpretation are presented for copper deposits in Chile, Mexico, and the United States.

Jan 1, 1995

By C. G. Cunningham

The Marysvale volcanic field of west-central Utah contains large areas of argillically altered rocks (fig. 1) that, in turn, enclose smaller areas of fine-grained, medium-grade, replacement alunite deposits and coarsely crystalline, high-grade vein-type alunite deposits. The largest replacement alunite deposits are [ ] located peripheral to a 23-m.y.-old monzonite stock called the Central Intrusive (fig. 1). The deposits formed in near-surface, highly oxidizing environments at the tops of hydrothermal plumes that were spaced irregularly around the stock. The deposits are horizontally zoned from alunitic cores through kaolinitic to propylitic envelopes. Vertically, characteristic alteration minerals progress from a pyrite-propylitic alteration assemblage at the base, upward through alunitic, jarositic, and hematitic assemblages to a flooded silica cap as shown on figure 2. The silica caps are cut by hydrothermal explosion breccias. d34Sso4 values of + 11.5 to + 15.4 permil indicate that sulfur in the hydrothermal plume was derived from underlying Mesozoic evaporites. The sharp upward transition from pyrite- propylite to alunite probably marks the paleowater table, and the top of the flooded silica cap represents the paleoground surface. Basin-Range extensional tectonism began shortly after alteration, and buried the replacement alunite deposits in basins beneath sediments eroded from uplands. The deposits were only recently exhumed.

Jan 1, 2013

By Roy A. Grancher

?The Horn of Plenty seems to have sprung a leak?.? anonymous For the first time in the Nation's peace-time history, shortages have become a way of life for the United States. Such words as scarce, tight, and critical are used in regard to supply, leading to priorities, allocations, and possible rationing as make-shift attempts to satisfy demand. Almost every day a new type of shortage appears in another product area that has traditionally been taken for granted as being in perpetual abundance. The range of coverage extends from basic commodities such as oil, chemicals, cement, steel, copper, cotton, etc., through to machine tools, motors, bearings, electronic components, etc. , to those finished outputs that satisfy our fundamental requirements for food, clothing and shelter. Signs of the times appear in cancelled airline flights, unfilled lines at gasoline stations, no available home freezers, lengthy delays in any furniture deliveries, or to that little old lady seen walking out of a local supermarket clutching her hoard of twenty rolls of toilet paper. What a sad commentary to have to make about our Land of Plenty, so long the envy of the World for its material wealth -- and today with its initials "U. S." seemingly standing for ?Unlimited Shortages.?

Jan 1, 1974

By Thomas F. Pugsley, Wilf J. Davies, James Gallagher

Falconbridge Limited is developing a major nickel mine at Craig which lies between 600 m, 915 m and 1500 m below surface and is accessed on the 600 m and 1250 m levels of Onaping Mine. To supply adequate ventilation for mine development and initial ore production, two raises, 1200 m long are to be driven in norite and granitic gneiss. Falconbridge has purchased a Robbins 97RL Raise Drill and a string of 330 mm drill pipe to ream these raises in 600 m legs at diameter. The paper describes the introduction of deep hole, large diameter raise boring technology into Falconbridge operations involving contractors and specialists in the technology.

Jan 1, 1989

By Timothy F. Markey, Brian C. Strohm

This paper presents a case study which applies risk assessment techniques in evaluating potential environmental problems associated with past waste disposal practices at a 65 acre non-ferrous metals and metal alloys manufacturing facility. Waste management activities at the site involved a number of surface impoundments for gangue material, neutralized acid rinse waters, acid rinse sludges, demolition debris, storm water runoff, stockpiled ores, and a permitted residual waste landfill. As a result of these activities, the She contained 9 identifiable waste management areas impacted by over 35 potentially hazardous chemicals and metals. Extensive environmental data obtained from investigations at the Site revealed heavy metal and volatile organic chemical contamination in various environmental media. These data were utilized to evaluate potential risks to human health and the environment. The human health risk assessment estimated potential health risks to workers, residents, and Site trespassers under current and expected future uses of the Site. Areas of the Site were identified which were considered to present potential health concerns under the various exposure scenarios. Results from the human health risk assessment were utilized to develop cost effective risk based soil remediation goals protective of the public health and environment.

Jan 1, 1992

The solution mining review did not arrive in time for publication in the May issue. The term solution mining is commonly used to refer to heap leaching, dump leaching, in situ mining and bore hole slurry mining technologies. The US Bureau of Mines is continuing with research in these areas. Commercial application of these technologies is progressing. There is an ongoing cooperative research project between the Bureau of Mines and the Santa Cruz Joint Venture to evaluate in situ copper mining at a field site near Casa Grande, AZ. The project is currently in the environmental permitting stage. The Bureau is preparing an environmental assessment for the project as part of the National Environmental Policy Act. The Bureau is also continuing with laboratory experiments to study the leaching characteristics of atacamite ore from the field test site, as

Jan 1, 1993

By L. Adler

In spite of distractions from glam-our areas (ground control, computers, etc.), excavating and bulk handling in mining remains paramount but is now undergoing dramatic advances. The massive intervention of mining and civil engineers as "engineer-users" into the tight, exclusive, and specialized bond between the equipment operator ("operator-users") and the manufacturer (mechanical engineers "and sales "reps") has now occurred. Three developments have accelerated this: 1) larger, more costly, complex, specialized, and innovative equipment; 2) a more profound understanding of the equipment, operations, and working conditions (encumbered space); and 3) a concurrent thrust into "high-tech," (automatic and remote controls, sensors, automation, artificial intelligence, and even robotics) and human factors (workload intensity, work-station design). This has produced a well-defined professional discipline, including construction and even military engineering. The mine plant, and to a lesser extent, the mine face, is now being monitored. Equipment conferences, journals, and centers at universities and agencies have multi-plied. The discipline's impact on future mining now becomes more apparent.

Jan 1, 1988

By C. D. Anderson

"IntroductionTungsten carbide is a valuable material used in a variety of different applications, including the manufacturing of cutting tools, bearings and as a cost-efficient alternative to industrial diamonds. Both the high hardness value (Mohs 9) and scratch resistance of this material make it a valuable commodity for use in the mining industry.Usually, the production of tungsten carbide is a multistep process involving one or more of the following unit operations: hydrometallurgical digestion, solution purification, crystallization (as ammonium paratungstate), calcination, hydrogen reduction and carbon synthesis. The proposed three-step process eliminates three of these steps (crystallization, calcination and hydrogen reduction) by implementing a combination of hydro/pyrometallurgical techniques. These include alkaline pressure leaching, carbon adsorption and carburization roasting. By eliminating some of the intermediate processing steps, there is potential to reduce energy consumption and decrease overall operating costs.Methods and resultsInitially, alkaline pressure leaching with sodium carbonate (Na2CO3) was employed to selectively leach tungsten, as tungstate (WO4 2-), from an industrial Scheelite (CaWO4) flotation concentrate. Experimental variables included lixiviant (Na2CO3) concentration, temperature and residence time. Experimental constants, based on previous work, were percent solids at 13 wt% and agitation at 400 rpm (Queneau and Strathmore, 1969). Leaching results showed it was possible to extract 97% of the tungsten present. The most favorable conditions for leaching were determined: 2M Na2CO3, temperature of 180° C and a residence time of 30 minutes."

Jan 1, 2015

By Erik Westman, Benjamin Mirabile

"Ongoing research is being conducted to evaluate secondary support performance in longwall ventilation entries. In a three-entry longwall gateroad, secondary supports are applied in the #2 entry to maintain a functional airway for the entirety of second panel mining. This airway represents a pathway for contaminated mine air to travel from the longwall tailgate to the mine bleeder system. The ground response curve concept may be used as a design basis for selection of appropriate secondary support in these ventilation entries. Two types of secondary supports are monitored for load and convergence in this project. These monitored supports are pumpable crib supports and interlocking wood crib supports. To evaluate the effect of support density, two installation patterns are monitored for each support type. Both a single-row, protected airway pattern and double-row, full entry support pattern are monitored for each support type. Load and displacement data is collected for all support patterns as second panel mining retreats past instrumentation sites. Data is collected for approximately 200-feet inby the second panel face or as long as safely possible. Load and convergence data collected will be used to calibrate numerical models that will simulate ground response curves for the #2 entry inby the second panel face.INTRODUCTIONWhen a bleeder ventilation system is used, the #2 entry of a three-entry longwall gateroad system is designed to function as a pathway for contaminated air from a longwall face to the bleeder system during second panel mining. The #2 entry is subject to substantial ground movement and loading during its function as an air course because it is a single entry between two longwall gobs. Secondary support is regularly applied in this entry to maintain air course functionality during second panel mining.Research on performance and design of secondary supports has been conducted extensively over the last 30 years (Barczak and Gearhart, 1993; Barczak and Gearhart, 1994; Mucho, Barczak, and Dolinar, 1999). This research has focused heavily on the application of secondary support in longwall tailgate, with little research on the application of secondary support in bleeders or other ventilation entries (Mirabile and Westman, 2018). Secondary supports in #2 entry are likely to experience similar loading and ground movement as those applied in the tailgate entry. However, the designed lifespan of the mine entry and the definition of acceptable ground conditions differs from mine entries where more extensive research has been conducted."

Jan 1, 2019

By Len H. Steele

To date VMD have designed, built and supplied nine autoclaves to various mining companies in Canada, the US, and Papua New Guinea. Initially, completely fabricated and lead lined units were shipped. The logistics of Placer Dome's Porgera PNG Project necessitated fabricating and lead lining each autoclave in five sections for transportation to site, each piece weighing approximately 30.5 tonnes. Support equipment such as turning rolls, automatic and manual welding machines had to be set up on site to facilitate assembly of these units which was a challenge in planning. This on site erection programme was completed in three months.

Jan 1, 1992

By R. M. Schuster

This study attempts to compare the costs of transporting coarse coal by pipeline, versus the more conventional use of belt conveyors. Hydraulic conveying of crushed (not pulverized) coal has not had widespread commercial acceptance. However, there is little doubt that the technology is available, so that, should this method be proven economical for a given application, implementation of this technology will become more acceptable. Hydraulic transport by pipeline between the mine stockpile and the coal preparation plant, for distances normally considered practical for an overland belt conveyor, should be an ideal application. In this application there is no need for dewatering facilities at the receiving end of the pipeline, because, the receiving screens at the plant serve this purpose. Further, clarified water from the preparation plant can be recirculated back to the mine, a plus for water resource and environmental considerations.

Jan 1, 1982