Search Documents

By W. B. Mather

A SURVEY of the technical literature concerned with oil well drilling methods and particularly with rate of penetration by various cutting media on different types of rock provides a mass of conflicting data. This is especially true with respect to, (1) the relative efficiency of diamond, rotary and percussion drilling operations; (2) the costs of the various types of drilling; and (3) the hardness factor of various types of rock and cutting media. The latter is the particular phase of the subject discussed here. The cause of the confusion may be attributed partially to a lack of 'basic knowledge concerning the physical properties of the cutting media and of individual types of rock. It is also due in part to a general lack of uniform standards in the industry for evaluating the hardness versus drillability of rocks while possible errors in interpretation by the authors of the various papers pertaining to the subject may be an additional cause of misunderstanding. The hardness of a mineral is defined by Dana' as "the resistance which a smooth surface offers to abrasion." Webster' states that hardness is "the cohesion of the particles on the surface of a body (as a mineral) as determined by its capacity to scratch another or be itself scratched." Rock hardness, although not usually defined in publications describing rocks, is assumed to be the same as the minerals which compose the rock or the resistance of the rock to abrasion. Drillability of a rock may be defined arbitrarily as the rate at which rock is penetrated by a definite type of drilling tool with the assistance of a specific type of cutting surface or medium and under speci- fied conditions as to speed of rotation and applications of pressure. Eventually the term penetrability may have to be employed to include any method of making boreholes in rocks, since methods other than those using conventional cutting surfaces are already in operation. A case in point is the jet piercing methoda which employs an oxy-acetylene flame as a means of penetration. The word hardness as used by the drilling fraternity has a variety of meanings which depend upon the type of drilling method employed. For example, in diamond drilling, hardness is interpretated as resistance to abrasion. In percussion drilling the term implies resistance to impact or indentation, while in rotary drilling, hardness is considered anal-agous to compressive strength. The three types of hardness—abrasion, impact and compression—are conflicting variables for different types of rock. Nevertheless, the term hardness is applied indiscriminately by the industry for the resistance of rock to penetration by any type of drilling technique. Abrasion Hardness Since 1818, Moh's scale of hardness, although only relative in nature, has been accepted universally as the method of measuring mineral and therefore rock hardness. In 1933, Ridgway, Ballard and

Jan 1, 1952

By J. W. Leonard, J. C. Anderson, C. T. Holland

PREPARATION CONTROL IN UNDERGROUND MINING Selective Mining According to district Depending upon the particular geographic loca- tion or seam characteristics, modern raw coal preparation practices can be used to obtain improved product quality and uniformity. Nevertheless, certain coal markets may require only marginal quality while others may require very high quality, and these objectives may be sought by commencing the preparation of coal underground at the "working face." Under- ground preparation involves choosing those portions of the seam which can be cleaned to satisfy predetermined market requirements involving ( 1 ) maintenance of uniformity in chemical quality, (2) elimination of removable impurities, (3) control of sizes and size ratios, and (4) control of moisture. The methods employed to attain these objectives vary widely with the (1 ) seam under development, (2) mining equipment available, and (3) changing trends in the consuming markets. When a mining property is opened and development progresses from one section to another, the (1) petrography of the coal in the seam does not remain uniform, (2) character of roof and floor are subject to change, and (3) character and prevalence of mineral impurities are subject to considerable variation. The quality of coal shipped to market from any mine depends upon intelligent foresight, planning, execution, and supervision. Mining becomes a highly technical art. The quality of coal as determined by chemical and petrographic analysis is without question one of the most important considerations in the development and life of any coal-mining property. Variations in such proper- ties as volatile matter, ash, sulfur, Btu content, and petrography are of considerable interest, and to a limited extent so are such properties as phosphorous content, free swelling index, plasticity, hardness, pressure formation during coking, and ash composition. The maximum and minimum specifications of these characteristics as established by competitive market conditions place definite limits on the marketability of a coal.

Jan 1, 1979

By Zamel GI

The utilisation of fossil fuels, including coal (of which Australia is a large producer and exporter) is a significant contributor to the emission of greenhouse gases. Methane gas, formed during the coalification process, is present in coal seams to varying levels depending on the rank and depth of the deposit. This gas usually escapes to the atmosphere during mining operations without prior conversion to C02 or utilisation as fuel. The quantity of methane released can represent from less than one percent to more than five percent of the carbon content of the coal mined. Per unit of carbon, methane has a greenhouse impact many times that of C02. The emission of uncombusted methane to the atmosphere can therefore represent a greenhouse impact of similar porportions to that of the CO2 formed by combusting the mined coal. However, greenhouse emissions from coal can be minimised by collecting the coal seam methane and converting it to water vapour and the less damaging form, CO2. If such conversion is carried out while performing useful work, the methane can further reduce greenhouse emissions by displacing other fossil fuels. Technology has been developed to allow coal seam methane gas to be economically collected in a pure form, uncontaminated with air. This pure methane can be used to supplement natural gas supplies, to generate power or for the production of chemicals or substitute transport fuels. By collecting and utilising coal seam methane, the greenhouse impact from the mining and use of coal can be minimised, with significant reductions possible in the case of gassy deposits.

Jan 1, 1989

The purpose of this paper is to describe two systems designed to provide estimations in stratigraphic orebodies for the purposes of detailed mine planning. The first is a completely geostatistical approach and the second is a combined geostatistical/deterministic approach. The essential features of both systems are the estimation of stratigraphic ore boundaries and the subsequent use of those boundaries to provide stratigraphic (or zonal) control for block and point grade estimation (kriging). Both systems are illustrated by application to a section of, the Hilton orebodies, Queensland, Australia.

Jan 1, 1989

By Lon D. Santis

This paper presents data and theorem to calculate the risk of experiencing undesirable lightning related events while blasting or while engaged in other lightning sensitive activities. The paper provides an overview of lightning hazards in blasting operations and a brief history of lightning related blasting accidents. Lightning continues to be the primary cause of premature initiations of explosives in mining; on average, over two such incidents are reported to the Mine Safety and Health Administration (MSHA) each year. The energy contained in lightning discharges and how this energy sets off explosives in mining is presented. Three categories of lightning warning methods: public media, lightning detectors, and atmospheric electrostatic field measurement are discussed. The remainder of the paper presents recently acquired data on the spatial characteristics of lightning development. This data is used to estimate the risk assumed by blasters under certain conditions. Risk estimations are made for electric and nonelectric blasting if persons are evacuated when cloud-to-ground (c-g) lightning approaches within a certain distance. For example, about 0.6% of all c-g lightning strikes have no other c-g lightning strikes within 25 miles in the previous 30 minutes. The paper shows that a typical blaster using nonelectric initiation in a high lightning density area with a 100% accurate lightning detector set to alarm at 25 miles would have a lightning caused unplanned detonation every 14,000 years.

Jan 1, 1998

By Aloke Verma, R. Singh, S. Jana, C. Sawmliana, P. Pal Roy

On July 21, 2004, a trial blast using electronic detonators was conducted in India for the first time in an opencast mine at Pundi-E Quarry of TISCO, West Bokaro. Orica-IEL conducted the test using electronic detonators. To provide necessary technical feedback on wider applicability, CMRI scientists also participated in the trial blast.

Jan 1, 2006

By A. C. Rice

Aminopolyacetic acid chelating agents were added to separatory-funnel-scale solvent-extraction systems to determine the effect on separating rare-earth elements. Average values for separation factors between adjacent elements obtained with Primene JM-T2 increase 36 percent when EDTA is added to the aqueous phase. Adding HEDTA or DCTA also improves separation factors for certain rare-earth elements. Percentage of extraction and the separation factors exhibit marked sensitivity to concentrations of amine, chelating agent, and hydrogen ion. The chelating agents improved separation in Primene JM-T, BHDA, and Primene 81-R extraction systems.

Jan 1, 1963

By Robert O. Vernon

The discussion of water and pit mining together is most appropriate. In fact, water can be considered a mineral and a well a narrow pit. Thus, of all the mineral resources mined, water is probably the cheapest, most valuable and least valued. The delivered price, including mining, transportation, storage and marketing rarely exceeds ten cents per ton, and our economy would cease without it. The time has come when the public must recognize that the extraction of a mineral resource from the land is a necessary and inevitable result of the industries? attempt to meet the demands of a growing economy. In so much of Florida, the lands mined can, with forethought and planning, be left as improved real estate, water conservation and management lands. On the other hand, the mining industries must face up to the need for the reclamation of land and compact with themselves, appropriate governmental agencies and with the mining states to restore mined lands to usefulness. Of limestone, sand, and clay 90 to 100 percent of the mined material is used, but with planning and specing, these pits, if they penetrate the water table, become valuable as real property. Phosphate, which returns about 70 percent of the mined materials to the pit, can reclaim the land for many purposes.

Jan 1, 1966

By Robert H. Carpenter

Downstream dispersion curves for certain trace metals were obtained from two mineralized areas in the southeastern U. S. In Lincoln Co., Georgia, 7 sample sets were collected downstream from the Magruder mine, a polymetallic sulfide deposit (Zn-Cu-Pb-Ag-Au) in metavolcanic rocks. Five sample sets were collected along Joe Mill Creek in Grainger Go., Tennessee, downstream from a zone of zinc mineralization in carbonate rocks (Mississippi Valley-type). In both areas, analyses were made of Fe-Mn oxide coatings on lithic fragments and quartz pebbles, and the -80 mesh fraction of the stream sediment. A comparison of the dispersion curves reveals the following: 1.) the anomaly/background ratio is markedly higher in the Fe-Mn oxide coatings for zinc and copper; 2.) the anomaly/background ratlo is markedly higher in the -80 mesh fraction for lead which is not concentrated in the coatings; and, 3.) the Zn/Mn and Cu/Mn ratios in the coatings are useful in that they enhance downstream derectability of mineralization as well as provide for a simpler analytical procedure. There are several potential advantages of using coatings vs. the conventional -80 mesh fraction in stream sediment surveys. Because soluble metal is brought into the stream mainly in groundwater, deeper anomaly sources may be detectable from the oxide coatings than from clastic fractions of alluvium where much of the metal is derived from erosion of soils. Variability due to sampling may also be reduced, providing better discrimination of anomalies. In areas of glacial or alluvial cover, coating surveys may be particularly applicable.

Jan 1, 1975

By J. R. J. Edwards

Jaspilite, a mineral consisting of silica and iron oxide in varying proportions, is one of the host rocks of the high grade ore deposits situated in the Middleback Range of South Australia. As a result of laboratory investigations, a flowsheet was postulated for the beneficiation of jaspilite to produce an acceptable grade product for feeding to blast furnaces, The flowsheet involved the reduction of the hematite in the haspilite to magnetite, the grinding of the reduced product to 95 pct minus 325 mesh Tyler followed by wet magnetic separation, hydroseparation and filtration to yield a magnetite concentrate. Agglomeration of the fine concentrate would then be necessary to meet the physical requirements of blast furnace feed. To prove the postulated flowsheet, to obtain a more accurate estimate of costs and to obtain design data for a commercial installation, a pilot plant was constructed at Whyalla, South Australia.

Jan 1, 1960

By N H. S Oliver

Five major veining events have been identified within the area surrounding the Mount Whaleback microplaty hematite deposit. These veining events can be directly correlated to the established deformation history of the Hamersley Province (Brown et al, in press). Vein formation temperatures of 203 to 231¦C have been obtained from primary fluid inclusions within veins which formed around the postulated time of ore formation. Preliminary proton induced x-ray emition (PIXE) analysis of these inclusions indicates KCl is the dominant salt species with varying levels of Ca, Fe, Ti, Mn present. It is suggested that some of these veins may have formed from feeder or effluent fluids from microplaty hematite ore formation.

Jan 1, 2002

By R. Frim, S. D. Ukeles

The present U.S. production of bromine is from inland brines located in Arkansas and Michigan. The most concentrated domestic brines (up to 5,000 ppm bromide)are situated in Arkansas. Less concentrated brines(about 2,500 ppm bromide) are located in Michigan. The amount of bromine sold or used in the United States came from three companies operating in those two states. Its value was $191 million. In 2004, the estimated U.S. bromine production was 222 kt (244,000 st). That compared with 216 kt (238,000st) produced in 2003.

Jan 1, 2005

By P. G. Carpenter, H. B. Fisher, W. E. Bergman

The conditions under which barium carbonate can be used to remove sulfates from drilling muds are limited The amount of sulfate remaining in solution in the system after treatment with barium carbonate is shown to be a function of the concentration of the carbonate and barium ions and the concentration of other electrolytes. Barium hydroxide may advantageously replace barium carbonate when the contamination is not entirely due to anhydrite (calcium in the system is then stoichiometrically less than sulfate) or when the carbonate concentration is high. The effect of substances such as quebracho, phosphates, and chromates, which form complexes or precipitates with barium, is discussed. INTRODUCTION As the complexity of the operations in drilling for oil has increased, more attention has of necessity been directed to the problems pertaining to the maintenance of good drilling mud properties. As a result, chemical treatment of muds has become an important factor in recent years. Some of these treatments have been designed to eliminate the deleterious effects of contaminants in aqueous mud systems by precipitation or other means. The most common of substances encountered during drilling include sodium chloride, cement, and calcium sulfate while various other contaminants: usually in small amounts, may be introduced from the water, clays, and other materials used in preparation of the mud. In certain cases, for example where continued salt-water flow is encountered or massive anhydrite is drilled, special muds may be used so that the physical properties of the mud will remain satisfactory for drilling. In other cases, it is desirable to remove the contaminants so that soluble electrolytes in the system are maintained at low values. For sulfate contamination, the conlmon practice in the field is to add barium carbonate to precipitate the sulfate as barium sulfate Ordinarily such a procedure gives satisfactory results. There have been important instances, however, where addition of barium carbonate was not effective in removal of soluble sulfates from drilling muds. and it is to these cases that the present paper is directed. While it is generally known that barium carbonate is not always effective in removing soluble sulfates from drilling muds, certain inconsistencies appear in the literature as to the limitations of its use, and little explanation for the limitations are given. Varnell and Kimbrel state that "the treatment (with barium carbonate for removal of sulfate) is simple and consists in maintaining a pH of 9 with caustic soda and quebracho." They caution that concentrations of quebracho greater than 1 lb./bbl. may inhibit the reaction. In another publication', a pH of 10.5 is considered "the maximum desirable," and the indication is that as much as 2.5 lb. quebracho per barrel may be present in the particular mud under discussion. Lancaster and Mitchell5 state that appreciable amounts of phosphates in the mud will inhibit the reaction with barium carbonate and that the phosphate treatment should be discontinued at least 24 hours before addition of the carbonate. Experimental work was initiated to ascertain the factors involved in using barium carbonate for the removal of sulfate contamination in drilling muds. While the experimental data herein reported are limited, they focus attention on the pertinent factors which must be considered for successful treatment. These factors are discussed from a practical and a theoretical view, the latter being supported by equilibrium data found in the literature. Further, it will be appreciated that the factors involved in this specific study will be closely analogous to those in certain of the other chemical treatments which involve a precipitation of the soluble contaminant. A thorough comprehension of these factors should result in a more fruitful application of this type of chemical reaction to the treatment of drilling muds. EXPERIMENTAL A. Reagents Two muds were used during this investigation. For one series of tests, bentonite suspensions were prepared by dilution of a stock suspension containing 8 per cent by weight of bentonite (Aquagel). For another series, a 6.4 per cent ben-tonitic mud weighted to 9.7 lb./gal. with barium sulfate (Mag-cobar) was used. Distilled water was used in all preparations. The quebracho (72% tannin extract) was obtained from the Thompson-Hayward Co. of Tulsa and contained 11.4 per cent moisture (105 C.). All other materials were reagent grade, and concentrations were corrected for water of crystallization, if any. All concentrations are expressed in pounds per barrel (42 gallons). B. Technique The systems — either mud or water — were contaminated with either sodium or calcium sulfate after treatment with the desired amounts of sodium hydroxide and quebracbo. For treatments with barium carbonate an approximately 3-fold excess (5 lb./bbl.) was used over that computed to be required to precipitate all the sulfate as barium sulfate. Barium hydroxide was used in concentrations of 2 lb./bbl. — about

Jan 1, 1949

By Emmanuel N. Zevgolis

After the Krupp-Renn process was shown to be unsuitable for treatment of the Greek nickeliferous laterites, the LM process was developed. It involved roasting reduction up to metallic iron in a Rotary Kiln (R/K) and smelting in an Electric Furnace (E/F). Ferronickel (with 15% Ni) produced in the E/F, was upgraded to 90-95% Ni in an 02 converter. Raw Ni was then electrolyzed to pure Ni. The LM process was not applied for very long however, due to various problems. So, the Larco process was developed, i.e., pre-reduction in R/Ks, smelting of the calcine in E/Fs for ferronickel production (15% Ni) and enrichment to 20% Ni, in an O2 converter. Until now, many technological improvements have been invented and applied or adjusted to the process, which have made it a fully reliable and competitive one. sohe of the improvements were the invention and application of a new granulation process for liquid ferronickel, the modification of the existing R/Ks, E/Fs and converters and the design of new ones, and others that are described in the paper. Keywords: Ferronickel, metallurgy, laterites, LM process, Larco process

Jan 1, 2004

By A. Dienenthal

"The casthouse floor has always been one of the most dangerous working places on a blast furnace or a ferro-alloy/nonferrous furnace. Apart from working in an atmosphere including toxic gases, fumes, and dust, the workers have to perform hard and heavy manual work close to runners and ladles filled with hot liquid metal and slag.Before the invention and installation of tapping equipment the tap-holes were opened and closed manually. Opening was done by means of steel bars and sledgehammers, whereas the tap-hole was closed by repeatedly ramming small amounts of clay or refractory material into the tap-hole, again with the help of long, heavy bars. In addition, on blast furnaces the blast had to be stopped, since it was impossible to close the tap-hole properly against the blast furnace pressure. This stoppage of the blast resulted in regular losses of production. Around 1900 a major change in technology occurred. Samuel W. Vaughen, superintendent of the blast furnace department of the Cambria Iron company at Johnstown, Pennsylvania (USA), invented the first clay gun in 1895 (Wiley, 1896) (Figure 1)."

Jan 1, 2014

By N. S. Stoloff, R. G. Davis

It is concluded from an X-ray stztdy that the formation of the hcp Mg3Cd superlattice is a nuclea-tion and growth reaction. A two-phase, ordered-plus-disordered, region is observed between 153" nnd 141"C. A maximum in the flow stress is observed both at temperature and in quenched specimens within the two-phase region. The peak arises fro112 the extra energy required to create antiphase boundary upon cutting the ordered regions. Hardening during isothermal annealing in Mg3Cd has been shown to be similar to the domain hardening in Cu3Au-type alloys in that up to the maximum the structure is ordered domains growing into a short range ordered matrix. The hardening is due to a combination of short range order strengthening and the strengthening produced when antiphase boundary has to be created. In a recent study1 of the effect of long-range order upon the mechanical properties and deformation modes of hcp Mg3Cd a comparison was made be- tween quenched (disordered) and slow-cooled (fully ordered) specimens. The most striking observations were that the disordered alloy yields at a much higher stress than the ordered alloy, and that there is a change in slip mode from primarily (_0001) ba_sal slip in the disordered state to (0001), {1010}, {1122}, and {l011} slip in the ordered state. The main purpose of the present work is to extend these observations to determine whether MgsCd exhibits a peak in flow stress at an intermediate degree of order, or at a critical domain size, as do other orderedstems. However, disagreement exists about the Mg3Cd order transformation with respect to: 1) the location of the critical temperature for order, 165°C or 153"~,' and 2) how the degree of order varies with temperature. Welber et a1.5 concluded from specific heat measurements that the formation of Mg3Cd is a second-order reaction with the degree of order a continuous function of temperature, while Moore and Raynor concluded that it is neither a first-order reaction, with the degree of order a discontinuous function of temperature, nor a second-order reaction. Consequently it was considered necessary to undertake an X-ray investigation into the change in degree of order and structure in the

Jan 1, 1964

By T. F. Tomb

This paper describes field and laboratory investigations conducted on a dust-collection system recently designed for integral use with a continuous mining machine. The results of the field study showed that the average respirable dust concentration measured at the machine operator's position was reduced by about 60 percent (from 8.7 to 3.5 milligrams per cubic meter), and total and respirable dust concentrations in the return air were reduced by approximately 70 percent. The data indicated that approximately 20 percent of the dust generated at the face was not passed through the scrubber. The lab-oratory results showed that the overall efficiency (by particle count) was approximately 80 percent for total dust concentrations (minus 20 micrometers in size) typical of those encountered underground. Calculations based on total dust concentrations measured during the underground study indicated that the respirable mass concentrations of the effluent from the scrubber would still exceed acceptable levels even if scrubbing of all the air at the face were possible.

Jan 1, 1973

Rio Tinto Iron Ore is currently working towards finalising comprehensive Native Title land access agreements, which cover all of the current eleven mines and infrastructure owned and operated by the company in Western Australia's Pilbara region. Critically, the agreements represent a mutual commitment to a long-term relationship and address many areas of concern by promoting indigenous enterprise, well-being and regional development opportunities. Our objectives in the process are to obtain the informed consent of the traditional owners for our Pilbara expansions while providing benefits to them in a way which provides lasting and substantial improvements to health, education, housing and real jobs in the mainstream economy.   To facilitate the agreement negotiations, Rio Tinto Iron Ore (RTIO) proceeded in 2005 to research and design a specific strategy around Aboriginal relations and local community engagement in the Pilbara. Wherever we operate, Rio Tinto follows a fairly simple formula in working with communities, which is comprehensively aligned to local context.   This presentation provides an overview of Rio Tinto Iron Ore's community engagement strategy in Western Australia's Pilbara region. It will also explore the establishment of regional standards on employment, business development and contracting that have been developed to ensure Indigenous people are engaged in the development of their region and are able to contribute to supporting the growth and development of mining in the area with the expectation that there is prosperity for all. This is an ABSTRACT ONLY no paper was prepared for this presentation.

Jun 1, 2010

By Alfred E. Pugsley

PAYMASTER CONSOLIDATED MINES, LIMITED, began an investigation into the economy and use of detachable bit drill-steel in June, 1937. This investigation has continued to the present time, and was made necessary by transportation and distribution difficulties that had arisen through the use of standard steel in three widely separated mine areas serviced by a central steel-sharpening shop. Detachable bit drill-steel performance was first studied in the workings of No. 2 mine, where the rock being drilled was composed mainly of porphyry or tourmaline, and where standard drill-steel transportation costs had been excessive. The results obtained in this early work definitely established the economy of detachable bit drill-steel at No. 2 mine. This conclusion was reached when the 're-grind' system of re-sharpening dulled detachable bits was 1n use. Preliminary observations on the performance of detachable bit drill-steel in the quartz-carbonate veins of No. S and No. 6 mines gave encouraging results, and warranted a large-scale investigation under practical mining conditions. All drilling operations were gradually changed over to use of detachable bit drill-steel. This change was completed by February, 1938.

Jan 1, 1939

By L. A. Neumeier

The Bureau of Mines evaluated creep and other properties of extruded Zn-30 pct-AI alloys containing 0 to 0.7 pct Mg. The alloys were extruded both above and below the Zn-Al eutectoid temperature of 275° C. Creep behavior is defined for the alloys as extruded and after various heat treatments. Tensile properties, hardness, thermal expansivity, impact resistance, and microstructures are given. The alloys, either with or without magnesium, required substantially less pressure for extrusion near 275° C than at higher or lower temperatures. The alloys containing magnesium exhibited significantly greater hardness, tensile strength, and creep resistance, but much lower ductility than the 2n-30 pct Al alloy. The properties were very sensitive to the processing conditions.

Jan 1, 1971