Search Documents

By R. W. Watson

At the request of the Mine Safety and Health Administration (MSHA) the Bureau of Mines evaluated the potential hazards of three compressed oxygen self-contained self-rescuers (SCSR's) designed for use in under-ground coal mines. The evaluation followed the lines used in a similar investigation of chemical self-rescuers and involved laboratory experiments as well as field trials designed to simulate a mining environment. They included bullet impact, bonfire, feeder-breaker impact and feed-through, and mining machine runover tests. The work showed that the units were not inherently unsafe but that under certain conditions of extreme abuse they can present a potential ignition or explosion hazard. This, coupled with a survey of reported damage on SCSR's currently deployed in underground mines, which indicated a relatively high frequency of incidents leading to the destruc-tion of the units, led to new recommendations on the deployment of SCSR's. The recommendations formulated by MSHA state that the units should be either properly worn by the miner, stored in heavy containers, or otherwise protected from situations in which they might be accidentally ruptured or destroyed, such as runover by mobile mining equipment.

Jan 1, 1984

Under the Town and Country Planning Act 1977 the Ministry of Works and Development has a responsibility for providing information to local and regional planning authorities on public works and matters of national development and importance, for the exercise of their responsibilities under this Act. One such matter which has recently become a source of concern is the development of South Island lignite. In 1979 the Ministry of' Energy produced a position statement outlining a programme of' research leading to the possible extraction of lignite in Southland or Central Otago for conversion into about 50 per cent of New Zealand's liquid fuel requirements by 1995. Understandably this possibility has caused considerable concern at the local level, expressed particularly by bodies such as Federated Farmers and the local authorities. In the absence of any factual knowledge short of mere conjecture been able to recommend to local authorities is that they limit their planning period to ten years. After this time more information regarding the size, nature, location and certainty of the proposal will permit a more accurate assessment of the implications of the York. While on holiday earlier this year I took the opportunity to visit opencast mining areas in Germany and England to gain an appreciation of the scale of impacts involved and discuss with those concerned the procedures used in planning for such operations. What follows is a brief description of these operations, a comparison with the likely development in this country and the extraction of what may be some relevant principles of' operation for the planning of an environmentally acceptable project. Please note that the views expressed in this paper are mine alone and are not necessarily those of the Ministry of Works and Development.

Jan 1, 1981

By Sidney Katell

Philippine laterite and serpentine ores can be utilized in an electric furnace operation to produce both a steel ingot and a ferronickel product. Figure 1 is a schematic interpretation of a plant in which laterite and serpentine ores are processed separately to obtain both ferronickel and steel as products. A relationship of estimated capital requirements and probable returns has been established in this study for a plant of this type. No attempt has been made to evaluate the risks involved in commercial operations. At such time that the project might be constructed and placed in operation, changes in the costs of material, labor, and power may materially affect the profitability aspects of this study. One of the uncertainties involved in the economic evaluation is the cost of mining, handling, and shipping the ores. It is on this basis that the cost of ore delivered at the plant is assumed to be variable at $3, $5, and $7 per net ton (dry basis). For all other costs a plant site at Iligan City, Philip-pine Islands, has been assumed in preparing the economic characteristics for a plant that will process 2,000 tons4/ of ore per day. Results of the study, for the 2,000-ton plant, with all monetary values expressed in terms of United States currency (Philippine peso valued at $0.50), are summarized as follows:

Jan 1, 1962

By B. W. Gandrud

The upper part of the Alabama deposits of crystalline graphite consists of an oxidized ore derived from, the underlying unoxidized ore through prolonged weathering. The degree of oxidation in different sections and at different depths within the bed is nut. uniform. The original ore is hard and blue-gray; the weathered product is soft and brown and is the only part that has been mined to any extent. Samples of both oxidized and unoxidized ores were obtained from two of the large graphite deposits of Clay County. Three additional samples of oxidized ore were obtained from different portions of a third property in the same region. In this report, ores 1 to 5 are of oxidized material and ores 6 and 7 of unoxidized.

Jan 1, 1934

By Miguel Gutiérrez

This paper will seek to provide an awareness of the challenges the permitting process presents to the engineering design for open pit mining projects in Perú. This awareness will create a better understanding of the permitting process within the several groups in mining companies that are responsible for getting the mine project started or continue its operations.

Sep 21, 2013

New Zealand has often been quoted by metallurgists and others as one of the countries in which Tellurium is found, and locally it has been recorded that appreciable quantities of tellurium have been met with in the Thames and surroundingdistricts. However, specimens containing tellurium which have been obtained on this field have not been preserved and their scarcity today points to the fact that tellurium is not here abundant.To ascertain its distribution, analyses and assays have been made by the author on a large number of ores, the results of several of which are given below.The presence of any considerable percentage of tellurium has an important bearing on the metallurgical treatment of ores in which it is found.

Jan 1, 1901

By Sam G. Demou

Drag bit cutting tests were conducted chiefly to determine bit forces encountered in rock types representing a range of compressive strength and hardness and thus enable the design engineer to estimate a continuous miner's performance in a range of rock types. Testing was carried out on the Bureau of Mines uniquely designed, instrumented rock cutting device (RCD). This device can make 3-ft-long cuts at various depths and speeds to approximate full-scale drag bit cutting by continuous miners. Point attack and cutter bits were tested on four rock types ranging in compressive strength from 7,200 psi (trona) to 29,600 psi (Valders white rock). Cutting tests were made at depths up to 1 in and speeds up to 70 in/sec. Data included normal and cutting forces, groove depth, groove width, and weight of rock broken. The effect of varying the cutting speed was determined, and specific energies were calculated for the various conditions. The bit wear was also observed. For the rocks tested, compressive strength and hardness are good indicators of forces, specific energy, and wear encountered. Results, especially bit wear observations, show the possibility of extending continuous miners, already being used in trona, to Indiana limestone (10,000 psi). Rapid bit deterioration precludes use in Tennessee marble (16,800 psi) and Valders white rock (29,600 psi).

Jan 1, 1983

By Xu H.

In recent years, the mineral applications dealing with more complex data in distributed environment have grown rapidly. Many mineral and mining organizations have to organize internally and globally distributed manufacturing and experiment sites, which share the roles of databases and other multi-services like software programs. Thus, there are commercial and technical pressures pushing the mineral software vendors to move their current service toward Web service. XML has gained wide acceptance for representing, storing and transferring structured data and documents of many kinds, especially in scientific communities. However, so far there is no such a Markup Language in mineral industry. A XML-based uniform encoding, which is called MineML(Mineral Markup Language), is proposed and developed in this project. The framework of the MineML specification is created. MineML will play the role as shared protocols within mineral domain for archiving, transferring the multi-nature data between the software packages on the desktop over the Internet and sharing the services between users at different sites. Inspired by MLA’s (Mineral Liberation Analyser, JKMRC, University of Queensland, Australia) Mineralogical Data Presentation Program, a proof-of-concept prototype of Web Service is developed here to validate and demonstrate the MineML specification. Certain strategies, specific technologies and tools are adopted to create such an environment. To accomplish that, a set of experimental MineML documents including correlated XML, XSD (schemas) and XSL(stylesheets) documents have been elaborated for archiving, presenting and transferring the mineralogical data information, with the persistence on flexibility and extensibility for generic mineral and mining data handling.

Jan 1, 2003

As the surface reserves are being depleted, more and more stone operators are seeking underground mining options. Stability of underground openings is a major concern for the safety and productivity. This paper relates to a field study conducted at a large underground limestone mine in Central Pennsylvania. Identification of hazards leading to ground failures and assessment of roof fall risks are important in mitigating injuries. Field observations at this mine were integrated with Roof Fall Risk Index (RFRI) mapping software recently developed by West Virginia University. The system is designed to combine field study data related to geologic factors, mining-induced damages, roof profile, and ground water influx to generate RFRI maps. The mine has adopted a proactive ground control program consisting of comprehensive examination of drilling and bolting logs; precision surveying of roof and rib; accurate mapping of cutters, falls, and geologic structures; and installation of extensometers and microseismic monitoring systems. Investment of time and resources has eliminated fatalities and lost-time injuries due to ground fall. This paper presents the geologic settings, mining conditions, ground control issues along with risk management and control techniques adopted at the study mine.

Jan 1, 2009

By Y. J. Wang

The selection of a shaft size for ventilation purposes is a classic problem of concern to mining engineers. This presentation is concerned with the sizing of conventionally-sunk circular shafts with concrete or shotcrete linings. Costs of sinking shafts of three different depths (from 500 feet to 1000 feet) and six different diameters (from 14 feet to 24 feet) were obtained through questionnaires to shaft contractors. The primary objective of the economic model presented is the balancing of detailed annual capital and operating costs to achieve the minimum overall cost of the shaft installation over its life. The economic model is similar to previous analyses but treats several of the individual cost categories in an updated fashion. Included in the paper is a detailed analysis of the effects of varying power costs on optimal shaft size. Also included are a statistical analysis of current shaft costs and comments on the choice between shotcrete and concrete linings.

Jan 1, 1977

By B. Genc

"The risk of spontaneous combustion is well known in the South African coal mining industry. In the coming years it is very possible that the incidence of spontaneous combustion will increase from current levels, due to factors such as an increased rate of mining, re-working of previously mined seams, more stooping and total extraction for underground mines, and higher stripping ratios for surface mines, leading to more spoils. It is also fairly certain that coal mining will face tougher environmental emissions legislation in the near future. To determine the areas where the risks of spontaneous combustion are high, it is necessary to improve on our current laboratory procedures for testing and evaluating coal samples, combining the results with site and field data, and if necessary revising the laboratory rating system to refine our understanding of South African conditions.Currently, laboratory tests are conducted in order to determine both the Wits-EHAC index and the crossing-point temperature which, when combined, give an indication of the spontaneous combustion propensities of the coal samples. This procedure has enabled the establishment of a database of results to review and evaluate South African coal seams. Using this database, the high-risk areas in terms of spontaneous combustion are identified. Tests have been undertaken for five consecutive years, between 2008 and 2012. In total, 119 coal samples from different coal seams and production coalfields have been analysed and classified through a series of laboratory tests. A comprehensive database of these results is available, and is continually being updated as new test results are added. This database will continue to expand, and to provide the basis for an improved risk evaluation methodology for spontaneous combustion"

Jan 1, 2015

By Russell R. McLellan

As part of an effort to develop new or improved placer mining technology in the Tertiary gold-bearing channel gravel of northern California, the Bureau of Mines conducted investigations at the old Badger Hill placer mine in Nevada County, Calif., to collect data and information regarding drilling and sampling methods and deposit characteristics. Sampling studies involved the collection and processing of 400 tons of large-and small-volume samples from drill holes, underground workings, surface pits, and blasthole rounds. A total of 355 samples averaging 2,296 pounds per sample provided reasonably accurate data for analysis of the gold distribution. These studies indicated that the bulk of the gold is within 40 feet of bedrock in stacked, lenticular zones of cemented gravel that are largely confined to the relatively narrow, meandering course of the deepest portion of the bedrock channel. Drilling studies involved the testing of truck-mounted rotary, buckett and vibratory drills, none of which proved to be a completely versatile tool for sampling quickly and reliably both consolidated and unconsolidated gravel..

Jan 1, 1974

By Thomas V. Falkie

In bygone days, the mineral engineer spent most of his/her time on the technical aspects of designing, building, and managing mineral operations. In the last few decades, mostly since the 1960s, increasing amounts of engineering man power and time are spent dealing with federal, state, and local government agencies, laws, and regulations. It is not possible to plan, design, build, or operate mines, mills, smelters, or even office buildings without detailed consideration of government regulations and permitting requirements dealing with environment, worker health and safety, etc. The four chapters of this section provide an overview of the social, legal, political, environmental, and health and safety aspects of mineral enterprise. The section sets the stage for the working engineer/geologist in industry, government, consulting, or academe and points the direction for more detailed study in each of these areas.

Jan 1, 2008

By C Moorhead, J Jones

A common problem in the mining industry is that company geologists can operate in relative isolation to the rest of the company (Jones and Moorhead, 2011). This may result in poor knowledge transfer and often priority conflicts with geology, operations and project departments. This problem is amplified by the acquisition of mineralogy capabilities and other metallurgical (met) test work undertaken by many companies in order to solve for complex orebody problems. Met data is often not located and viewed in 3D space so that geologists and engineers can create and work with geometallurgical (geomet) models (Bye, 2006). Visualisation of data in an interactive graphical 3D model provides a bridge enabling met professionals to collaborate with engineers and geologists to provide a common understanding of the relevance of geomet data.In recognition of this problem, Newcrest has undertaken an effective collaboration strategy to improve internal and external engagement through the use of large visualisation displays (Jones, 2009). The displays are underpinned by IT systems and information management practices that recognise the needs of underlying disciplines. Today it is generally understood within Newcrest that this is required to improve decision-making, deliver faster cycle times and improve governance.Collaboration in companies has been generally associated with the introduction of new IT functions (IBM, 2008). However, the science and engineering process that are used to structure modern IT-based collaboration systems and practices are now known to be simplistic compared to the long-standing practices associated with collaboration and knowledge management in disciplines such as geology and mining.CITATION:Jones, J and Moorhead, C, 2013. Geometallurgical communication as a distributed information system, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 133-138 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By D. K. Bose, R. H. Rakhasia, V. D. Shah, J. C. Sehra

A series of experiments was conducted to determine the effects of roasting temperature, soaking period and quantity of soda ash added. At a laboratory scale, under optimum conditions of roasting at 873 K for 2 700 s with soda ash 10 wt% in excess of stoichiometric, molybdenum recovery was 99%. The investigations indicate the technical feasibility of producing high-purity MoO3 by combining the roasting process with carbon adsorption/desorption. The process uses low-cost chemicals, can be scaled up readily and is free of the SO2 pollution generated by conventional roasting, as the sulphur content of the concentrate is converted to sodium sulphate

Jun 18, 1905

By John B. Goddard

In-situ leaching of uranium by aqueous ammonium carbonate containing oxygen or hydrogen peroxide as oxidant results in the partial dissolution of sulfides. While some of the sulfide sulfur is oxidized to sulfate, a considerable portion is oxidized only to thiosulfate and polythionates. Polythionates poison the anion exchange resin used to extract uranium. At the Palangana operation in southeast Texas, the trithionate ion (S3062-) was found by infrared spectrometry to be the major resin poison. Treatment of ion exchange feed solutions with hydrogen peroxide only resulted in partial conversion of reduced sulfur species to sulfate, and trithionate conversion was particularly slow. Poisoning of the resin also occurred from the ammonium chloride eluant, which built up trithionate because of recycling. This was essentially eliminated by chlorinating the eluant prior to yellow cake precipitation.

Jan 1, 1984

By Anna Carolina Cerqueira Neves

As fibras sintéticas vêm sendo gradualmente substituídas por fibras naturais. Em comparação com a fibra sintética, fibra natural demonstrou vantagens econômicas e ambientais. Visto que apresenta características interfaciais com matrizes poliméricas que favorecem a absorção de energia de alto impacto pela estrutura. No entanto, até agora pouco foi avaliado sobre a fibra de cânhamo incorporada em matrizes poliméricas. Este estudo tem o objetivo de avaliar a resistência ao impacto deste tipo de compósito com matriz de poliéster reforçada com diferentes porcentagens de fibras de cânhamo. A resistência ao impacto aumenta proporcionalmente com a quantidade relativa de fibras incorporadas como reforço na matriz polimérica. Este desempenho foi relacionado com a dificuldade de ruptura imposta pelas fibras, resultante da interação da matriz de fibra de cânhamo / poliéster de forma a ajudar a absorção da energia de impacto.

Aug 17, 2017

By W. Mackenzie

The development of a resource project inevitably requires the investigation of a vast range of issues across most engineering disciplines - mining, metallurgical, chemical, civil, electrical, mechanical and environmental - as well as the geosciences. It is also a characteristic feature of the resource industry that no two orebodies - and hence no two development projects - are the same. So these technical issues have to be addressed to a greater or lesser extent in evaluating any resource project's development potential. Not surprisingly then, technical issues tend to predominate when assessing the development potential of a project in the process typically referred to as `doing a feasibility study'. But the principal purpose of a `feasibility study' is to determine whether a development opportunity makes good business sense, not just whether it is technically possible. Resolution of technical issues is often seen as the primary focus of a feasibility study, whereas in reality, these technical issues are the basis upon which an asset delivery and business plan is built. This is not to say that technical issues are unimportant - they are a prerequisite to the demonstration of a project's viability. The feasibility study process must therefore demonstrate that not only have the technical issues been satisfactorily addressed, but also that the broader commercial, economic and social issues have been considered in the development of a comprehensive business plan, which includes an assessment of the risk-reward profile of the proposed development. This paper will present a framework for the conduct of `feasibility studies' and provide guidance to minimum standards and best practice.

Jan 1, 2007

By David C. Oyler, Dennis R. Dolinar, Christopher Mark, Craig S. Compton

Fully-grouted roof bolts comprise more than 80% of the primary roof supports used in U.S. coal mines. However, nearly 1,500 MSHA reportable, non-injury roof falls occur each year, and most of these are attributable to failure of the roof bolt system. Anchorage failure is one failure mechanism for fully-grouted bolts. As roof deformation works its way upward, the bolts can become heavily loaded near their upper ends. If the applied load exceeds the anchorage, the bolts will simply pull out. Research dating back 30 yrs indicates that this type of anchorage failure is most likely when the roof rock is weak, just where roof support is most critical. In soft shale or coal roof, the small amount of data available in the literature indicates that 20-30 in of resin anchorage may be required to achieve the full capacity of the bolt. In other words, the “full resistance zone” of a 60 in bolt may actually be just 30-40 in. Despite its potential importance, there is no widely accepted anchorage test for fully grouted bolts. Standard pull tests have sometimes been employed, but they provide no information on the anchorage near the top of the bolt. An alternative, first described more than 25 yrs ago in the U.S., is the short-encapsulation pull test (SEPT). With this test, the bolt is installed with only a short (1 ft or less) tube of resin. In recent years variations of this test have become international standards. v

By Ruilin Yang

"Blast vibrations are essentially a strain/stress wave propagating in rock or structures inthe vicinity of a blast. However, blast vibration has always been quantified in terms ofpeak particle velocity (PPV) or acceleration (PPA), and a meaningful relationshipbetween blast vibration and strain/stress has not been established. The determination ofthe dynamic strain from blast vibration may improve quantification of blast damage andselection of a blast vibration limit for critical structures or high walls. Dynamic strainrelates to rock mechanics or material strength more directly than peak particle velocity(PPV). This paper documents a method to calculate the three-dimensional dynamic straintensor from recorded blast vibration signals. The method is based on determination of thedisplacement gradient at a point of interest for each time instance during the vibrationduration. The method to calculate dynamic strain is applicable to generic seismicwaveforms including near and far field blast vibration from a production blast withmultiple blast holes. In order to minimize measurement errors the specifications of thespacing between monitors and the sampling frequency of the vibration recording aredescribed."

Jan 1, 2012