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By R. H. Schutz

TO ASSIST users in the selection of reliable and satisfactory respiratory protective devices, the Bureau of Mines bas established five schedules of minimum performance requirements for the approval of respirators. The current revisions of these schedules3 include 13D for self-contained breathing apparatus, 141F for gas masks, 19B and the amendments to 19B for supplied- air respirators, 21B for dust, fume, and mist respirators, and 23B for chemical cartridge respirators. Copies of these schedules may be obtained from the Bureau of Mines, Publications Distribution Section, 4800 Forbes Avenue, Pittsburgh, Pa., 15213. Approval tests on respirators are performed only at the request of the manufacturer4 of the respirator and at his expense. If the device meets the approval requirements, a certificate of approval is granted on the complete respirator. This certificate states that as long as the respirator is manufactured as originally approved, or in accordance with any changes covered by an extension of the original approval, the manufacturer may advertise and sell his respirator as being approved by the Bureau of Mines. Many industries and regulatory agencies require that respirators approved by the Bureau of Mines he used where respiratory protection is needed. The Bureau of Mines, however, has no regulatory power over the use of the respirators that it approves. It acts as an impartial testing agency to insure the availability of suitable and safe respirators.

Jan 1, 1966

By R. H. Schutz

TO ASSIST users in the selection of reliable and satisfactory respiratory protective devices, the Bureau of Mines bas established five schedules of minimum performance requirements for the approval of respirators. The current revisions of these schedules include 130 for self-contained breathing apparatus, 141F for gas masks, 19B and the amendments to 19B for supplied- air respirators, 21B for dust, fume, and .mist respirators, and 23B for chemical cartridge respirators. Copies of these schedules may be obtained from the Bureau of Mines, Publications Distribution Section, 4800 Forbes Avenue, Pitts- burgh, Pa., 15213. Approval tests on respirators are performed only at the request of the manufacturer of the respirator and at his expense. If the deice meets the approval requirements, a certificate of approval is granted on the complete respirator. This certificate states that as long as the respirator is manufactured as originally approved, or in accordance with any changes covered by an extension of the original approval, the manufacturer may advertise and sell his respirator as being approved by the Bureau of Mines. Many industries and regulatory agencies require that respirators approved by the Bureau of Mines he used where respiratory protection is needed. The Bureau of Mines, however, has no regulatory power over the use of the respirators that it approves. It acts as an impartial testing agency to insure the availability of suitable and safe respirators.

Jan 1, 1966

By Durell Denysschen, Rafael Abela

The recovery of gold from old mine dumps has been carried out over the last two decades. The gold value and price together with recovery methods, determine whether it is economical to process a dump. Pre-concentration with cyclones and spiral concentrators may offer a method to process dumps considered currently uneconomical to treat.

Jan 1, 2006

By M. D. Lawton, P. Steen

"Drilling results from the established levels at AngloRouyn Mines Limited had indicated inadequate tonnages to meet the planning schedule. It was decided to develop the main zone of the orebody below the bottom working level of the mine. The orebody dips north at an average of 50 degrees and plunges to the west at about 10 degrees. Due to the need for rapid development of this area, a decision was made to use trackless equipment.This paper describes the method used and highlights the use of small 5-ton diesel trucks as carriers for the 2-cu.yd LHD machine. The method achieved advances of about 1,000 feet per month, at a dip of 12 degrees over a length of close to 2,000 feet, using as few as 20 men per day."

Jan 1, 1971

By A. Sinha, N. K. Babar, H. R. Kalihari, A. K. Chakraborty, M. R. Saharan, C. P. N. Pathak

A case study is presented on the optimization of cable bolting patterns in cut-and-fill stopes at the Chikla Mine, MOIL, India. Rock mass characterization, using Bieniawski’s RMR and Barton’s Q, indicated that the stopes lie in the “no supports required” to “spot bolting required” support categories. In contrast, the current practice of cable bolting in a 2.0 m by 2.0 m grid pattern for stope widths less than 12 m displays different results. Numerical modelling results are in line with the rock mass characterization study. It can be affirmed, as well, that no cable is carrying rock loads greater than 5 t. This fact is derived from observational behaviour of the crown pillar of an experimental stope with open stoping operations and hanging cables in the cut-and-fill stopes of the mine. An increase in the cable bolting grid spacing is, hence, recommended for implementation by mine management, based on the study described in subsequent sections. It is also suggested that the mine adopt the open stoping method, provided results of a rock mechanics instrumentation program in an experimental stope with a cable bolting grid of 2.5 m square are favourable.

Jan 1, 2007

By R Aseervatham

The fast tracked mine development strategy attempts to blend feasibility studies and engineering/commissioning functions into a streamlined process. In this compressed process, environmental issues are difficult to control with respect to the optimisation of operational environmental performance. This paper presents a standard mine development process with specific focus on environmental issues, and contrasts this against Rio TintoÆs recent fast track experiences on the Hail Creek project (Australia), the Baranj project (India) and the Gokwe North project (Zimbabwe).

Jan 1, 1999

By Tiago Luis Anderson dos Santos Morais1 Oliveira

Em função da crise energética e do aquecimento global, faz-se necessário a utilização de novas fontes de energia como uso sustentável da matriz energética disponível. Do exposto, a CEMIG GT, a ONDATEC e a Universidade Federal de Ouro Preto, investiram em um projeto no âmbito do Programa (P&D) Cemig/Aneel para geração de energia. O objetivo deste trabalho foi efetuar a avaliação do potencial energético dos efluentes gasosos (gases não condensáveis – GNC) e líquidos (Gases Condensáveis) de uma planta de pirólise de biomassa via micro-ondas para a produção de carvão vegetal. Para tanto, a ONDATEC construiu uma unidade piloto de produção de carvão vegetal (pirólise) por micro-ondas com capacidade de produção de 150 kg por hora. O processo de pirólise ocorreu em modo contínuo e em dois estágios, a secagem da biomassa e a pirólise propriamente dita, com a produção de carvão vegetal, gás de pirólise (GNC) e bio-óleo (GC). Em face dos resultados obtidos para o GC e o GNC, foi verificado um potencial de geração de 2,24 MWh de energia elétrica por tonelada de carvão produzido, que pode ser uma boa alternativa para desonerar a cadeia produtiva do carvão vegetal e do ferro gusa.

Sep 25, 2017

By P Tzeferis

An exploratory laboratory work was carried out on microbial leaching of poor non-sulphide nickel ores, not amenable to conventional mineral processing operations. The results have shown that domestic low-grade lateritic ores of limonitic or haematitic type are amenable to bioleaching by fungal strains of Aspergillus sp and Penicillium sp. Maximum nickel and cobalt recoveries achieved were 60 per cent and 50 per cent respectively. Losses of soluble nickel in the fungal biomass were found in the range 3 - 11 per cent. Chemical analysis of the leach liquors showed the presence of significant amounts of citric, oxalic and other organic acids, indicating the role which certain metabolic products of fungal activity may play in the process. Possibilities for future investigations are discussed.

Jan 1, 1997

By C. Riveros, H. Henein

Bulk Metallic Glasses have a high potential as advanced engineering materials due to their various properties including strength and corrosion resistance, to name a few. This paper investigates amorphous phase formation and rapid solidification characteristics of impulse atomized Co-based alloys in order to understand and control the application properties of the final products. Amorphous fraction and kinetic crystallization properties of the atomized Co-based alloy powders were quantified by means of Differential Scanning Calorimetry. In addition, different but complementary characterization tools were used to analyze microstructures of the powders. These include optical microscopy, X-ray diffraction and micro-hardness tests. While the amorphous fraction within the powders is promoted by high cooling rate and smaller powder size as expected, hardness is found to decrease with the fraction of amorphous phase.

Jan 1, 2015

By FREDERICK C. BROWN

THE practice of fine-grinding is now being so successfully - carried on in some fields, notably in West Australia, and its advisability has been so frequently pointed out' that the matter in this paper is not put forward as being new ; its chief object being to call attention to the importance of fine-grinding in the treatment of comparatively low-grade ores. I have been engaged during the last five years in the cyanide-treatment of ores in the Ohinemuri district (North Island), New Zealand, and I consider that, in the near future, extremely fine-grinding (almost sliming) will become a very important feature of the milling-methods in this field, since it seems absolutely necessary to reduce the most of ores to a very fine state of division if a high extraction is to be obtained; and, in most cases, the extra percentage of saving will leave a good margin above the increased cost of treatment due both to the fine-grinding and to the interest on the capital spent for the grinding-machinery. The average ore of the Ohinemuri field is composed of a quartz-gangue with some calcite, carrying the gold-value in the form of an alloy of gold and silver in about equal proportions, and the silver-value in the form of mixed sulphides of silver, usually associated with a considerable amount of iron pyrites. In the upper levels, the ores are decomposed and carry large quantities of black manganese oxide and some iron oxide, but, as. depth is reached, the decomposed ore gives place to sulphides and, in some mines, rhodonite, manganese silicate, is present in fairly large quantities. The average value of the

Jan 1, 1906

By V. F. Parry, W. S. Landers

"INTRODUCTION The primary object of this investigation was to determine changes in physical and chemical properties of subbituminous lump coal while in storage for 8 months in a typical residence and to demonstrate how this fuel may be stored without degradation or spontaneous combustion. The second object of the study was to determine how the stored coal performed in a hand-fired furnace operated under practical conditions.The investigation revealed that if care is exercised in placing sub-bituminous lump coal in a closed bin, no significant slacking or degrada¬tion occurs, no hazards arise, and over-all indicated efficiencies of about 65 to 69 percent can be obtained under practical,firing conditions that the average home owner can meet.Owing to the war emergency, much attention is being given to the proper storage of coal, and campaigns are being conducted to increase the quantity of coal being stored to relieve transportation and production overloads. Ordinarily, coal dealers do not recommend storage of subbituminous coal in homes owing to deterioration of the coal and to possible hazards from spontaneous combustion. This practice has grown from some troubles that have been experienced, which can be traced to improper preparation, improper bins, and poor technique in placing coal in a bin. There is no good reason why subbiturninous lump coal cannot be stored safely in homes."

Jun 1, 1944

By Louis A. Panek

Determining the change of stress in rock based on measurements of the deformation of a drill hole is a procedure that is increasing in popularity. A closely related procedure involves the applicat10n of this principle to determine the existing stresses in a rock medium, by cutting free (core drilling) an annulus containing the drill hole. In this Bureau of Mines report, expressions are derived from which one can calculate the stress ellipsoid--the three-dimensional change of stress, or the existing three-dimensional stress field, as the case may be. Study of these equations shows that the stress components in three dimensions can be determined by measurements in only two drill holes, and yields general principles that are useful in planning an efficient program of drilling and measurement. Procedures are given for calculating the least squares estimates of the stress components and their standard errors, and for evaluating or comparing calculated values by means of standard statistical inferences.

Jan 1, 1966

By G. S. Hume

Dr. K. A. Clark: No one will doubt the statement of fact that, during drilling operations through the bituminous sand beds in the Mildred-Ruth Lakes area, the core-barrel was found to contain bitumen with minor amounts of sand instead of bituminous sand. But many will doubt the interpretation of this fact as meaning that beds of bitumen occur interstratified with the bituminous sand beds. They will prefer to hold faith in the laws of physics, which deny that sand will float on oil or that fluid under pressure will not flow away through a permeable medium, until it is proved that the appearance of the oil in the core-barrel was not due to circumstances surrounding the drilling of the bituminous sand beds. The implication of the interpretation that sand is floating on oil is clear and it is unacceptable. Bituminous sand is unconsolidated sand more' or less saturated with a viscous oil. It is as difficult to conceive of bituminous sand lying on top of a body of the viscous oil as it is to conceive of unconsolidated sand more or less saturated with water lying on top of a body of water. The only difference between the two concepts is that the oil is viscous whereas the water is fluid. Oil-soaked sand placed on viscous oil would, when released, sink through the oil slowly, whereas water-soaked sand would sink through the water quickly.

Jan 1, 1947

By Robert Stefanko

The widespread and increasing use of electrical power for mechanized power has made a tremendous impact on the coal mining industry. It is probably the single most important factor influencing the productivity of a coal mine. In fact, as a part of a study of 62 coal mines in Pennsylvania and northern West Virginia, plus information that was obtained from other sources, it was possible to show a direct correlation between the rise in the use of electrical power and mine productivity, Figure 1. This increased power demand has not always been achieved through proper planning and a careful evaluation of all design parameters, many of which are not even recognized. The result has been increasing problems in power distribution and utilization establishing the need for scientific studies including considerable underground measurements. Because the cost of power for ton of coal produced is generally a relatively low value, inadequate attention is paid its distribution and utilization. Furthermore, a poor system of records and a lack of adequate measurements add further to a paucity of statistical evidence that would permit a rational analysis of overall power costs. However, the direct cost figure alone is highly deceptive; of much greater value is the indirect costs associated with the use (or misuse) of electrical power underground. Success in highly mechanized mining correlates directly with equipment utilization. Today's machines have tremendous potential capacities but profits are measured in terms of performance and not potential. Thus the reliability of electric motors is an extremely important factor for consideration and the effects of all parameters should be carefully evaluated. Thus while studies are continuing on the evaluation of primary and secondary mine electrical systems with interesting results, this paper will be limited to reporting on the results of a study of a specific motor application.

Jan 1, 1972

By Stephen K. Pave1

Over 1,100 tons per day of Fluid Catalytic Cracking Unit (FCCU) catalyst is used worldwide. During the cracking reaction, catalyst is contaminated by deposited metals including nickel, vanadium, potassium, copper, iron, sodium, etc. To compensate for contaminants, a portion of the circulating catalyst inventory is withdrawn for disposal and fresh catalyst is added. The DEMETR process takes spent FCCU catalyst and removes a portion of the metal contaminants, enabling the refiner to recycle demetallized catalyst, thus reducing the solid waste from the refinery. Through August, 1993, the operation of one unit for one refiner has resulted in the recycling of over 7,500 tons of spent catalyst.

Jan 1, 1994

By J. E. Moran

A groupd of French capitalists, La Compagnie Française des Mines d'Or du Canada, has undertaken the considerable task of developing Otter creek, in the Atlin district, B.C., by hydraulic mining methods. It has long been known that the gravels of this stream carry sufficiently high values in gold to make it attractive as a mining venture, but it was impossible to ignore the existence of formidable natural obstacles to hydraulicing them, and these needed to be taken into serious account before embarking upon any costly programme of development. The tide to the Otter Creek leases was originally held by Mr. H. Maluin, a French engineer well known throughout the north, to whom was to fall the task of financing whatever programme might be decided upon. It was he, too, who would have to assume the responsibility of finally passing judgment upon the practicability of the various devises for overcoming the adverse natural conditions. With an infinite attention to detail, which I believe to be a characteristic of the French people generally, he studied his problem and was finally able to submit to his financial backers a programme which left the very minimum possible to the hazard of accident or chance. Dr. Mandy, on his visit to Otter creek this season, expressed the opinion that our method of opening this difficult creek presented certain features which might be successfully applied in placer operations elsewhere in British Columbia, and it is largely for this reason that the present paper has been prepared. I shall set forth, as well as I can, the practices which have enabled us to overcome rather easily some of the obstacles which nature had unkindly placed in the path which we must take. The natural flow of water in Otter creek is far too little to deal success-fully with the rather excessive amount of glacial drift overburden which lies directly over the gold-bearing gravels. For this natural defect, the only remedy was to procure more water. This we have clone through a system of flumes and ditches, totalling between ten and eleven miles in length, which bring to the mine a supply of water adequate for our needs.

Jan 1, 1932

By Allen S. Smith

Analysis of the helium content of a natural gas presents more than the usual difficulties encountered in applying the thermal--conductivity method because of the relatively small amounts of this inert gas present and the wide variation in the other constituents. However, the numerous advantages of this method and its adaptability to continuously recording and control instruments make it worthy of consideration. A specific application of the method described yields quantitative results only when used with gas mixtures of known qualitative compositions which vary within predetermined limits. Periodic analyses for the helium content of a producing gas well may be conveniently made by an absorption method3/ and a continuous analytical method is not necessary for this purpose. Natural gas containing 1.75 to 1.90 percent of helium produced from Government-owned wells is processed in the Amarillo (Texas) Helium Plant of the Bureau of Mines. The helium extracted in the plant is supplied to the Army and Navy, and the processed natural gas is sold to a commercial gas company4/. As complete recovery of the helium in the raw material is not economically practicable, the processed gas contains 0.1 to 0.3 percent of helium, depending upon conditions of operation;- Production is checked against the helium removed from the gas, which before the installation of the thermal--conductivity apparatus was calculated from the analysis of a cumulative sample of the processed gas. As conditions of operation affect the residual helium content to a large extent, a composite sample was an uncertain index of the efficiency of the process.

Jan 1, 1934

By J P. Evert

Didipio gold-copper mine operation is situated in the island of Luzon, approximately 270 km north of Manila in the Philippines, in an area of high seasonal rainfall. The hydrogeological water flow model implied that there would be high connectivity between regional structures and underground operations. This model predicted that underground mine groundwater inflows were expected to quickly rise as the decline progressed to a peak of 510 L/s. Designing a capital pump station to deal with 510 L/s has its own challenges, however developing the decline down to the required level, always dealing with 300 L/s of water and constructing the pump station is extremely challenging and required a robust water management plan and mine design. When dealing with expected high volumes of water, underground mine design and scheduling plays a key role in protecting electrical infrastructure, equipment, secondary pumps, and the decline from flooding. A good drainage system and controlled dewatering plan is essential for safety and progress. This paper details the dewatering techniques and mine designs required to accomplish decline development with high water inflows as used in the Didipio project. It will describe the learnings and outcomes that are achievable with a flexible design, as new structures are mapped, and water intersections are increased. It also highlights the potential for adaptability in mine planning to provide evolving improvements or to evade problems that are expected from the constant reconciliation of data recorded during development.

Mar 29, 2023

By D Baas, D Bennett

This paper describes how Brisbane-based PanAust Limited develops process control strategies that are implemented at all operations and are used in functional descriptions for plant upgrades and new projects.The process control strategies are determined by operating management philosophies designed to maximise returns from the company’s assets.The approach is endorsed in the project planning and design phases to ensure facilities and equipment that form the major production assets are fit for purpose and capable of enabling the production managers and operators of the projects to maximise shareholder returns.PanAust’s process control approach has been to develop sets of process control standards which focus on two key areas. The first area covers hardware requirements and architecture, software objectives, control models and individual loop tuning methods. The second area defines control room layout, graphic standards and the alarm philosophy. The application of these standards in a new plant or upgrade decreases the time required to achieve design capacity and optimal performance.The PanAust process control strategy changes the operator’s role from one that controls a number of individual loops to one that sets the control objectives of the processing plant. To achieve optimal performance, all the process areas of the plant are analysed to identify opportunities to improve throughput, recovery and stability. Once a key opportunity is identified, a process control strategy is developed which defines the objective of the control, its functionality and how an operator will interact with it. After development of the control model the operators assist engineers to test and debug it. Once the model is robust, it can then be duplicated throughout the group and developed as a group process control standard.CITATION:Baas, D, Bennett, D and Walker, P, 2014. Developing process control standards for optimal plant performance at PanAust Limited, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 325–334 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By Peter A. Hacquebard

Recent drilling programs have shown that the in-situ coal resources of Nova Scotia are very substantial. The grand totals of the measured, indicated and inferred categories amount to 232 m, 646m and 993 m tons, respectively. This vast quantity of coal occurs essentially in five main fields: Sydney, Mabou, Port Hood, Pictou and Springhill. The largest resources (84% of the total) occur in the submarine area of the Sydney coalfield. With a 65% recovery rate, there are at present 150m tons of proven, recoverable coal in Nova Scotia. At a predicted maximum annual production of 5 m tons, this amount equals a lifespan of 30 years. However, additional drilling, particularly in the Sydney offshore area, holds promise of increasing the recoverable reserve tonnage to at least 350 m tons. This figure may be compared with the 484 m tons production obtained during 191 years of mining (from 1785-1976). The geological appraisal of the remaining coal resources in the five fields mentioned is presented in three-dimensional diagrams, per individual seam and corresponding reserve area. In addition, the submarine extensions of the Sydney and Mabou coalfields are discussed in light of results obtained from off shore oil exploration wells. The terminology and standards of coal resource calculations are pointed out, and the phenomenon of seam splitting and its prediction from geological data is illustrated. The availability in Nova Scotia of either thermal or metallurgical coal is considered in relation to rank and sulphur content. This paper was presented in June 1977 at the 90th Annual Meeting of the Mining Society of Nova Scotia. The coal resource estimates, however, have been updated to include the results obtained with the offshore drilling in the Sydney Coalfield to November 1977.

Jan 1, 1979