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By E. Quaquero

This article reports on the current state of an ongoing research project which is aimed at implementing intelligent models for hardly predictable hazard scenarios identification in construction sites. As past evidences showed that no programmatic action can deal with the unpredictable nature of many risk dynamics, we tried to survey on how the current approach for safety management in the construction industry could be improved. In our previous research the use of Bayesian networks elicited from subjective knowledge were preliminarily tested. Those networks might be meant as a reliable knowledge map about accident dynamics and they showed that a relevant ratio of occurrences fall in ?hardly predictable hazards? class, which cannot be warded off by programmatic safety measures. This paper reports the second outcome of our research project, which focused on the development of first elementary fragments, regarding the occurrence of a possible ?hardly predictable scenario?. Instead of experts? contributions (who, over their carrier, seldom incurred in accidents), we used ?legal cases? as an accurate source of information. They suggested which categories of ?hidden hazard scenarios? are more likely to happen. We found that the most frequent hidden hazard scenarios are linked to operator?s negligence and abnormal behavior, e.g. irregular removal of scaffolding?s components, unprotected openings, improper use of PPE, etc. Every pattern determined by legal cases has been formalized by a fragment (i.e. elementary network) of the overall Bayesian network. Finally, all the elementary networks were integrated into a comprehensive intelligent tool for realtime hardly predictable hazards prevention. The final setup, asked for interfacing these intelligent models to a low-level sensor network and used to feed them with inputs about the current state of the context, is discussed too.

Aug 1, 2013

By Z Li, Z Yan, M Yang

Recycled cement paste (RCP) is a kind of CaO-rich recourse, which is separated and recycled from waste concrete. Due to its chemical composition, RCP could partially replace lime as a flux and be loaded into electric arc furnace (EAF) steelmaking process. Rapid RCP assimilation and liquid slag formation have significant effects on EAF steelmaking process. In this study, the dissolution behaviours of RCP and lime at temperatures of 1400°C to 1500°C were investigated using static dissolution experiment. The dissolution rate, interfacial microstructure, as well as dissolution mechanisms were discussed. It was found that the dissolution rate of RCP was much higher than that of lime. RCP could be completely dissolved into slag in 60 secs at 1500°C. The dissolution rate of lime was in range of 3.910-4 g/(cm2ꞏs) to 2.610-3 g/(cm2ꞏs), while that for RCP was in range of 1.510-3 g/(cm2ꞏs) to 4.910-3 g/(cm2ꞏs). As for lime dissolution, a dense layer of dicalcium silicate (C2S) generated at the dissolution interface, and the diffusion of Ca2+ in C2S layer was the limited step for lime dissolution. Some of calcium ferrite could be observed at the interface between lime and C2S layer. As for the RCP dissolution, there is no obvious product layer of C2S formed at the dissolution interface, Fe2+ continuously diffused into RCP layer during the dissolution, and small amount of FeOꞏMgO solid solution generated and gathered at the dissolution interface. The dissolution rate of RCP in EAF slag was quite higher than that of lime, partially add RCP as flux in EAF could accelerate the slag formation process.

Aug 21, 2024

To solve the mining safety and health needs of the future, access to, and sharing of, timely and relevant information will be crucial. The next generation of the Web will provide tools (RDF, OWL, SPARQL, etc) to define and link content for more effective discovery, integration, and reuse across applications and organisations. A recent Gartner Research Report (Finding and exploiting value in Semantic Web technologies on the web, May 2007) predicts these technologies will begin to coalesce in ten years. Implementing this Semantic Web requires structured web content described via metadata (information about information). If an industry or enterprise bases its metadata on a common vocabulary, it becomes possible to share and reuse information. The National Institute for Occupational Safety and HealthÆs (NIOSH) Mining web site provides access to more than 1500 NIOSH-developed publications, products, and topic pages on issues as diverse as ground control, respiratory diseases, and mine emergency management. As the site has grown, locating content has become increasingly difficult. To improve the searching process, a panel of internal experts representing all major research programs was established to develop a controlled vocabulary for indexing that content. The outcome is the NIOSH Mining Safety and Health Thesaurus, a faceted, hierarchical thesaurus containing hundreds of mining safety and health terms organised into 20 facets (eg diseases, injuries and disorders; hazardous events and exposures, equipment, engineering and administrative controls). One immediate goal of this project is to reduce the complexity of locating information on the NIOSH Mining web site by implementing metadata and faceted information retrieval techniques. Another goal is to stimulate discussion in the international mining community regarding developing metadata standards so the industry is ready to adopt future Semantic Web technologies to improve access to mining safety and health information.

Jan 1, 2008

By B J. Wight, R Mackay, S Kim

Improving the understanding of the processes governing ground movements in and around brown coal open cuts is of significant interest for both operating stability and rehabilitation. Brown coal, lignite, is a low-rank coal that is best described as a soft rock, with geotechnical characteristics that derive from its organic origin. It is well-known that low-rank coals exhibit creep behaviour; however, little has been reported on the impacts of chemical processes on brown coal creep behaviour even though organic substances are susceptible to chemical alterations and mining processes will contribute to changes to the geochemical environment; around most mines, groundwater flow patterns are altered leading to enhanced surface water infiltration. Here we study the deformation behaviour of brown coal in response to ion exchange reaction. Our experimental results show that for different ion exchange conditions different characteristics of secondary compression are observed. With the addition of Ca2+, the ratio between coefficients of secondary and primary compression (Ca /Cc) initially decreased, presenting a minimum value at the concentration of 0.005?M, then increased significantly. This implies the importance of ion exchange process for the long-term deformation of brown coal. On the other hand, increasing Na+ concentration did not affect Ca /Cc values significantly over all tested concentrations. The suppression of diffuse double layer was still observed for Na+-treated samples as increasing Na+ concentration decreases Ca values. From a practical perspective, this study did not consider the tertiary creep behaviour and eventual creep failure.CITATION:Kim, S, Mackay, R and Wight, B J, 2014. Creep due to chemical alteration of rocks – a case study in brown coal, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 61–64 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By E. C. Ekedahl, R. J. Heath

Introduction Potassium, together with nitrogen and phosphorous, is an essential nutrient required for growth. Since all living things need potash, the major demand for potash - about 95% of the total - is as a fertilizer. Agricultural productivity has increased dramatically in recent times. This increase in crop yields requires substantial amounts of added nutrients to keep the soil fertile. It follows then that potash will always be in demand. There is no substitute. Other fertilizers that contain phosphorous (P) and nitrogen (N) are complementary and not competing products. Fireplace ashes (pot-ashes) have a relatively high potassium content. Their value as a fertilizer had been recognized for centuries. But today's potash industry did not begin until deposits of potassium-rich ore were discovered and exploited in Europe during the 19th century. Canadian potash development Potash in Saskatchewan was first recognized in 1943. It was discovered as a byproduct of an oil exploration program. But it was several years later before the existence of a major commercial deposit was acknowledged, and not until 1951 that the first attempt at development occurred. That attempt was unsuccessful. The shaft flooded and was abandoned. It did, however, demonstrate the need for new technology to penetrate the waterlogged Blairmore layer. This was eventually developed and the first mines were brought into production in the early 1960s. Once the technology was available, and the extent and quality of the potash beds became known, a number of companies proceeded to develop mines. By 1970, seven mines were in operation and three more were nearing completion. Combined, total capacity then was 7.6 Mt/a (8.4 mil¬lion stpy) K20. At that time, world potash consumption was about 15 Mt/a (16.5 million stpy). This increase in supply from Canada produced a large potential surplus that shattered the prevailing balance between supply and demand. Although world demand increased steadily throughout the 1960s and early 1970s, it was several years before world supply and demand were again in balance. Saskatchewan capacity has been expanded a number of times. It now stands at 10.7 Mt/a (11.7 million stpy) K20. Actual production has not approached this figure, however. Two new mines in New Brunswick have recently been built with a combined annual capacity of 1.2 Mt (1.3 million st) K20. Total Canadian capacity of about 12 Mt/a (13 million stpy) now amounts to 30% of world capacity. Central offshore marketing organization Canadian Potash Exports Ltd. (Canpotex) was created in 1970 as the offshore marketing organization for Canadian producers. Canpotex is owned by Saskatchewan producers and is their exclusive marketing organization for offshore business. Each company handles its own sales in Canada and the US, but all sales to other markets are handled through and by Canpotex. The Saskatchewan industry has an ore body of a size and consistency unmatched anywhere in the world. Large efficient mines have production costs that compare favorably with other producing countries. On the minus side, Saskatchewan is remote from most major markets. It therefore needs the ef¬ficiencies that stem from one organization that coordinates all offshore shipments and minimizes distribution costs. Agriculture guides potash market In the period following World War II, potash was a classic growth industry. World demand increased each year from 1945 to early 1970s. Since then, demand has been more erratic. Some years show substantial increases, but are followed by significant declines. For about the last decade, the pattern has been unclear and future demand has become correspondingly difficult to predict. North America and Europe together account for about 40% of the world potash consumption. In both areas, farming is characterized by surplus production, declining crop prices, and expensive government support programs. Under those circumstances, farmers respond by minimizing input costs. Fertilizer is one of the items they reduce. Potash is retained in the soil. It is possible to reduce potash application with no immediate deterioration in crop yield. The lower yields occur only when potash levels are depleted. So, farmers can econo-

Jan 12, 1987

By Robert J. White

Strong's equation for calculating bottom-hole pressure reduction due to gas cutting of drilling mud is corrected, resulting in a simpler equation which is easier to use. Use of the equation is illustrated by examples. It is shown that reduction of weight of a 10 lb/gal mud by 50 per cent at the surface due to gas cutting produces only n 3 per cent decrease in hydrostatic head at the bottom of a 5,000-ft well. It is also shown that at the surface 5 volumes of air per volume of mud are required to reduce the apparent mud weight from 8.5 to 6.5 lh/gal in a 3,000-ft well. Illustrative graphs are included to show the effect of various degrees of gas cutting on apparent mud weight at depths of 2,000, .5,000 and 10,000 ft and to show variation of apparent mud weight, with depth for a 100 lb/cu ft (13.37 lb/gal) mud gas cut to 90 lb/cu ft (12.03 lb/gal) at the surface. INTRODUCTION In 1938, Strong' published the following equation for calculating reduction in bottom-hole pressure due to gas cutting of drilling mud h = 1/D [p + pn/100 In p + p(1-n/100)/p(1- n-100)] where: h = depth in feet P = pressure in atmospheres at depth h due to mud column only D = hydrostatic pressure in atmospheres of a col-umn of uncut mud 1 ft high p = back pressure at well-head (in atmospheres) n/100 = fraction by volume of gas in mud at well-head at back pres-sure p This equation was recently found to contain an error due to an incor-rect expression for variation of vol-ume fraction of gas with pressure. Values calculated by the original equation are close to the correct values for small percentages of gas for which it was derived but become increasingly erroneous as the gas content increases and are completely unusable at the very high gas con-tents employed in aerated mud. DERIVATION The nomenclature used is the same as in Strong's paper. The pres-sure dP exerted by a lamina of thickness dh at a depth h ft is ex-pressed by Eq. 1 where x = volume fraction of gas at depth h dP = D (l - x)dh . . . (1) When we express x in terms of the wellhead per cent gas n, the well-head pressure p and the pressure P at depth h, the result is Eq. 2. x = (np/p+p)/(100-n) + (np/P + p) When this is substituted in Eq. 1 and rearranged to separate the var-iables the result is dh = 1/D [dp + np/100-n dp/(P + p]. Integration between appropriate lim-its results in or if the wellhead is open so that p = 1 atm and we rearrange Eq. 4, the result is loss in head = hD — P = n/100-n In (P + 1) ...(5) Eq. 5 can be solved easily by successive approximation using hD as a first approximation for P on the right-hand side and calculating a first value for loss in head. This can then be used to get a new value of P using the left-hand side of the equation. Values converge very rap-idly even for quite large values of per cent by volume gas n. EXAMPLES The effect on bottom-hole pressure of 50 per cent gas cutting of the mud in a 5,000-ft well using 10 Ib/ gal mud will be calculated, we have: h = 5,000 ft 10 X 7.48 144 X 14.7 = 0.0353 atm/ft hD = 176.5 atm n = 50 Substituting these values in Eq. 5 and using hD as a first approxima-tion of P on the right, we have, approximate loss in head = 50/50 In (176.5 + 1) = 2.30 log 177.5 = 5.17 atm. We calculate a new value of P as follows:

Jan 1, 1958

By Binbin Luo, Northeastern University, Chuanyao Sun, Jie Liu, Yimin Zhu, Yanjun Li

"A series of new type collectors a-bromo-saturated fatty acids, CH3(CH2)5CHBrCOOH (a-BHA), CH3(CH2)7CHBrCOOH (a-BDA), CH3(CH2)9CHBrCOOH (a-BLA), CH3(CH2)11CHBrCOOH (a-BMA) were synthesized from saturated fatty acids and bromine by solvent-free method (Hell-Volhard-Zelinski reaction) in laboratory. The micro-flotation tests of quartz mineral were conducted at a relatively low temperature of 15 °C. The adsorption mechanism of such collectors on quartz mineral surface were established by zeta potential measurements, in conjunction with the results of quartz micro-flotation tests. The flotation results showed that the collecting ability is in the order of a-BMA > a-BLA > a-BDA > a-BHA for the flotation of quartz mineral, which also demonstrating that the a-bromo-saturated fatty acids (a-BFAs) are new selective collectors for reverse flotation to remove quartz mineral from iron ores at a relatively low temperature.INTRODUCTIONThe requirement of higher pulp temperature to maintain the activity of fatty acid anionic collectors which have been widely applied in technological process of iron ores reverse flotation lead to a great deal of energy consumption.The purpose of this paper is to synthesize a new modified collector with carbon chains from eight to fourteen atoms, with strong electronegativity bromine atom introduced into a-carbon position to improve the activity and solubility of the reagent so that it can be adopted at a comparatively low pulp temperature. The collecting performances of these new collectors on quartz surface were studied, and the structure - properties were discussed in light of zeta potential measurements and quantum chemistry calculations."

Jan 1, 2016

By Jong-Jip Kim, J. G. Byrne, W. Kim, In-Ok Shim, John E. Flinn

"Two rapid solidification processes for 304 stainless steel were studied: centrifugal atomization (CA) in a helium atmosphere and atomization by exposing argon-containing melt to vacuum (VGA). Positron annihilation and x-ray line broadening measurements of explosively consolidated monoliths were used to clarify microhardness measurements as a function of annealing temperature. Interesting differences in positron response between CA and VGA materials are ascribed to more carbide formation in the CA material than in the VGA material in the 600 0C range. In addition, hot isostatic pressing of the CA material was examined as to the relations between mechanical behavior, pore shape, and relative density. A variable stress concentration factor is introduced into the theory to allow for changing pore shape as relative density increases.IntroductionThere are many potential advantages of rapid solidification processing (RSP), such as a high degree of matrix supersaturation, finely dispersed microstructures, improved chemical homogeneity, and retention of metastable phases, which have been studied extensively. To consolidate rapidly solidified material which is in powder form into useful shapes often requires subjecting the material to elevated temperature for extended periods of time under mechanical forces, as in hot isostatic pressing or hot extrusion. In such cases, some of the characteristics of the rapid-cooling step can be strongly affected. An alternative is dynamic consolidation (1), for example by explosive forming, where the time frame at least is extremely short.In the present work, effects of the consolidation processes of hot isostatic pressing (HIP) and explosive forming in a die are examined. The particular material is 304 stainless steel. The characteristics of both RS and VGA 304 stainless-steel powders were described by Wright, Flinn, and Korth (2) earlier."

Jan 1, 1988

By C. P. Lawhon, J. P. Simpson, W. M. Evans

Data obtained under controlled test conditions using a microbit drilling machine showed that oil emulsified in water muds may either increase or decrease the drilling rate, depending upon drilling conditions. A low-viscosity oil such as diesel fuel can give drilling rates in limestone almost equal to that of water. Data obtained for water emulsified in oil muds showed little decrease in the drilling rate in water-saturated cores as the water percentage of the mud was increased above the 5- to 10-percent range. Changes in drilling rate were found to be dependent upon the oil or water concentration of the mud and upon the type of formation drilled. Changes in static filtration on paper (API filtrate) did not correlate with filtration while the mud was circulated across rock. INTRODUCTION Oil additions to water muds have been reported to increase drilling rates, provide hole stability and improve filtration control. Eckel' showed that water-base emulsion muds used in the West Texas area increased drilling rate with increasing oil concentration up to 15 percent oil by volume, but drilling rate decreased at a concentration of 20 percent by volume. Based on laboratory tests using water muds to drill shale, Cunningham and Goins' reported that drilling rates increased and tendency for the bit to ballup decreased with the addition of oil. Percentage increase in drilling rate varied with the particular formation. They showed oil additions to improve drilling rates ap proximately 75 percent in Vicksburg shale and as much as 150 percent in Miocene shale. Each investigation showed an optimum oil content for the particular formation. Most data that indicated improved filtration control due to oil additions were based on static API Eltrates through paper rather than dynamic filtration through permeable rocks. Some types of dynamic test give a better representation of filtration down-hole while drilling and might be more likely to show some correlation with drilling rate. Static filtration would be important, of course, in relation to hole stability and formation damage. This laboratory's drilling tests, conducted on water-raturated Berea sandstone, indicated that improvements in drilling rate were not evident with increasing oil concentration in water-base muds. Investigation also showed similarity between oil-emulsion (water-in-oil) muds and water-emulsion (oil-in-water) muds while drilling these formations. In Lueders limestone high concentration of water-in-oil muds and high concentration of oil-in-water muds provided the same relative drilling rates. In Berea sandstone there was a large reduction in relative drilling rate with both the oil and water muds that contained low percentages of emulsified fluid. Dynamic filtration rates of water muds on rock did not always decrease with increasing oil percentages even though the static API filtration rates on paper did decrease. Data observed in laboratory drilling of limestone and sandstone indicate that improvements in field drilling operations when water- or oil-emulsion muds are wed may not be the result of increased drilling rates but of improved hole conditions. In some cases, actual drilling rates might be slower but improved hole conditions will result in less total time on the hole. DEFINITIONS Mud pressure—Pressure of drilling fluid as measured after leaving the drilling chamber. This is considered as the approximate mud pressure just past the bit and at the face of the formation. Terrastatic pressure—Pressure representing weight of overburden. Formation pressure—Pressure of formation fluid as measured at outlet of drilling chamber. This is considered as approximate pressure of fluid in the pores of the formation. Differential pressure—Difference between the mud pressure and formation pressure. Relative drilling rate, percent—Drilling rate with experimental fluid divided by drilling rate with water times 100 equals percent. LABORATORY EQUiPMENT AND TESTING PROCEDURES The drilling equipment has been described in previous publications The microbit drill is a closed system (capacity, approximately 7 gal) that can be pressurized to 15.000 psi and heated to 500F. Main components are a drilling chamber, filter-heater, rotary-drive and variable-speed cir-

By R Dwyer

Iron ore currently mined in Australia generally requires very little beneficiation. However, depleting high-grade resources means that in the future low-grade iron ore deposits will need to be mined to meet the increasing demands of the global steel industry. Along with the increased demand, the industry faces additional pressure to reduce the environmental impact of mining and mineral processing. This has stimulated research beyond incremental improvements to conventional processing into alternative low-impact processes, including biotechnological approaches to mineral processing.Bioflotation and bioflocculation have emerged as relatively recent technologies, in which bacteria and/or their extracellular material may be used as flotation reagents (collectors or modifiers), enabling improved selective separation of minerals. The primary advantage is the production of a selective, environmentally-benign alternative to conventional flotation reagents. A biotechnological approach may also be taken in the beneficiation of high-phosphorous iron ores utilising bacteria capable of iron reduction and phosphorous solubilisation.Samples from three iron ore deposits in Western Australia were examined for bacteria suitable for iron ore benefi ciation. A number of common soil microorganisms including Pseudomonas spp, Limnobacter thiooxidans, Paenibacillus spp, and Ralstonia insidiosa were identified using culture-independent molecular techniques. A number of anaerobic species belonging to the genus Clostridium were also identified in the core samples. Selected aerobic species were enriched and isolated on high nutrient media in the presence of haematite. Several of the isolated strains showed an affinity for iron ore, attaching to haematite in enrichment cultures and further demonstrated through adhesion studies. Other isolated species such as Ralstonia isidiosa and Pseudomonas stutzeri are known to solubilise rock phosphates in soils and have potential for the removal of phosphorous from Australian iron ores.

Jul 11, 2011

By L Gobbo

X-ray diffraction (XRD) provides useful information about the composition of an ore sample in terms of quantification of crystalline phases and amorphous content. The use of new, fast detection systems implemented in CubiX FAST industrial diffractometers creates the opportunity to use this technique in exploration and modern process control. Besides the chemical composition of iron ores, their phase composition is also an important factor for exploration, quality control and processing. In the analysis of iron ore, XRD can identify the phases containing iron, such as haematite Fe2O3, magnetite Fe3O4, and goethite FeO(OH), and any other mineral phases present, especially silicas. Quantitative analysis is possible by various classical methods such as straight line or polynomial calibration with standards, but modern quantification analysis techniques such as Rietveld analysis or full pattern autoscale analysis are attractive alternatives, as they do not require any standards. These methods offer impressive accuracy and speed of analysis. Another analysis technique offering great benefit to ore exploration and process control is cluster analysis. This technique greatly simplifies the analysis of a large amount of data, eg from drill core samplings, and automatically sorts closely related scans of an experiment into separate clusters and marks the most representative scan of each cluster as well as outlying patterns. This can facilitate multi-dimensional compositional mapping of ore deposits, identifying regions of favourable mineral composition and allows fast and reliable tracking of the process. It is the most economic procedure to have automatic data evaluation without involving any dedicated personnel in the process. Details of the techniques used, sample optimisation methodologies, results, data precision and limitations will be discussed. The approaches have enormous potential as an inexpensive, reliable tool, useful in the characterisation of iron ore materials in an industrial environment.

Jan 1, 2009

By K. K. Clark

Excessive injection pressures in water injection wells may create deeply penetrating fractures, or may open up existing reservoir fractures. If these fractures are oriented toward offset producing wells, oil recovery at injected water breakthrough and ultimate recovery will be impaired. A method of calculating fracture lengths from pressure fall-off test data is presented. The method is based on a linear flow model that simulates conditions present during the early-time period after shutting in an injection well. Fracture lengths can be calculated directly if formation permeability is known. A graphical technique is presented that provides fracture lengths based on permeabilities calculated from normal fall-off tests, where those permeabilities are adjusted for flow geometry. Test data from four injection wells and results obtained from applying the method to these wells are discussed. Introduction Rates of water injection into nonstimulated wells in low permeability reservoirs frequently fall below economically desirable levels. Therefore, some form of stimulation such as hydraulic fracturing often is performed on these wells. Usually these fractures penetrate a short distance from the well — short as compared with interwell spacing — and therefore should not create problems of water channeling to offset producing wells. In the past, some operators have been tempted to increase injection pressures continually to maintain a specified injection rate. But pressures cannot be increased indefinitely. Field data indicate that continued injection above fracture opening pressure can cause excessively long fractures to approach between well distances. If these long fractures intersect or closely approach offset producing wells, premature water breakthrough can result. It is difficult to seal effectively these fractures by various workover procedures after premature water breakthrough has occurred. This paper describes testing procedures that are potentially capable of detecting premature water breakthrough before it occurs. Knowledge of fracture lengths and fracture opening pressures can assist field engineers in selecting optimum operating conditions for water injection wells. Fracture lengths should be calculated from pressure fall-off tests on injection wells, and maximum permissible iniection pressures should be determined from step-rate injectivity tests. Equipped with this information, the field engineer is in a better position to recommend for a particular injection well the optimum operating conditions that will lessen the chances of channeling to offset producers. Historically, pressure transient tests have been conducted primarily on producing wells and analysis procedures have been based on radial flow concepts. Several authors have suggested that these same procedures be applied to tests conducted on water injection wells. This application is justified for wells that are not connected to extensive fracture systems. However, if the formation is severely fractured, the interpretation methods must be modified. Several authors have presented the pressure response of various systems that are intended to simulate reservoir conditions. A paper by Russell and Truitt* on vertically fractured svstems is probablv the most useful from the standpoint bf the fieid engineer. Russell and Truitt presented the pressure-vs-time behavior of a well connected to vertical fractures with various fixed lengths. Their permeability adjustment technique is used in this paper to refine methods of calculating fracture length and interwell permeability. Theory and Definitions Three flow-system geometries are considered in analyzing injection well test data. These various geometries are applicable during specific time intervals of transient pressure tests. Schematic drawings of the flow models, and the time intervals over which they are applicable, are shown in Fig. 1 in the chronological order that they are applied to the pressure response of water injection wells in fractured formations. The very early response is simulated by an infinite linear system as shown in Fig. 1A. This representation permits the calculation of matrix surface area exposed to the fracture. The model shown in Fig. 1B is identical with the one studied by Russell and Truitt. They evaluated the transient pressure response of this vertically fractured system by finite difference techniques. The results were presented as tabulations of dimensionless pressure drop functions for a range of fracture lengths. A semilog plot of these data shows that the apparent matrix permeability can be related to the true matrix permeability by a simple exponential function. Their adjustment factor is used in this paper to improve the accuracy of matrix-permeability and fracture-length calculations.

Jan 1, 1969

By Michael W. Roper

McDermitt Mine is located in northern Humboldt County, Nevada, approximately 5 miles south of the Orgeon-Nevada line (Figure I), within the Opalite Mining District. The operation is a joint venture between Placer Amex Inc., San Francisco, and Mineral Exploration Company Ltd., a limited partnership. The McDermitt orebody possesses a discontinuous, gently dipping blanket-like form within 150 feet of the surface over an area 2200 by 2500 feet. The ore zone averages 20 feet in thickness. The ore minerals consist of cinnabar (HgS) and corderoite (Hg3S2C12) deposited parallel to bedding within argillized, Miocene age, tuffaceous lacustrine sediments. Exploration indicates reserves of approximately 3,000,000 tons ore at a grade of 10 pounds mercury per ton (0.5%) An open pit mining operation utilizing scrapers and bulldozers supplies a concentrator with 700 tons of ore per day. The milling operation consists of autogenous grinding, flotation concentration, concentrate dewatering, and tailing disposal, with a design capacity of 100 tons per hour. The furnace section consists of a concentrate filter, vertical six hearth furnace, mercury condensing system, and exhaust gas scrubbing systems. It has a design capacity of 1000 pounds of dry concentrate per hour. The McDermitt orebody is situated about 2000 feet north of the Cordero Mine which, with adjacent properties, produced over 115,000 flasks (76 pounds per flask) mercury from 1941 to 1972' Two other major mercury producers in the district have been the Bretz and Opalite Mines, located in southern Malheur County, Oregon, within 5 miles of the Oregon-Nevada line. Bretz and Opalite have produced about 14,800 and 12,370 flasks mercury respectively, from 1926 to 1965.1/

Jan 1, 1976

By F. A. Schaufelberger

Early work on chemical precipitation of metals from metal salt solutions is reviewed. The chemistry and thermodynamics of precipitating copper, nickel, cobalt, and cadmium metals by reaction with hydrogen are discussed. Mechanisms of metal precipitation, nu-cleation, growth, and agglomeration are reviewed, as well as some solubility phenomena of cleation,gases and solids at elevated temperatures. Experimental data presented deal mainly with the reaction of copper sulfate solution with Hz. METAL can be recovered from a leach solution either indirectly by precipitation as a compound that is later reduced or directly by electrolysis, cementation, or chemical reduction, for example, with hydrogen. The widely used electrowinning processes suffer from the inefficiency of converting fuel to low voltage dc and from low current efficiency when complete recovery is attempted. With the batch hydrogen reduction methods outlined here, a unit of fuel converted to hydrogen in modern gas reform plants will make two to three times as much metal as can be obtained with electrolysis. With continuous hydrogen reduction, four to six times as much metal is obtained. Precipitation by reducing a metal salt solution with H, has been known for almost 100 years.' Commercial use of the process, however, awaited the research and development program initiated by Chemical Construction Corp. Within the last few years this program has brought about construction of commercial plants, listed on p. 701. Ideal hydrogen reduction will precipitate a pure metal from a solution obtained by commercial leaching methods at a rapid rate without excessive temperatures and pressures. The metal precipitate will be of desired size and density, less than a percent left in the vessel being deposited on the wetted parts. The present discussion will outline Chemical Construction Corp.'s early development program and will discuss the chemistry and mechanics of reducing copper, nickel, cobalt, and cadmium from solution by H2. Work on selective reduction of nickel from cobalt has been described earlier.2 The article is not concerned with precipitation of copper by disproportionation of cuprous solutions where yield is limited" to 50 pet.* It does not discuss use of gaseous reducing agents other than hydrogen, such as SCV which may lead to contamination with sulfur, or CO," which is considerably more expensive than hydrogen and produces a gaseous reaction product, CO2.† The article does not include use of other nongaseous reducing agents: which are far more expensive than CO. Also, notes on the history, engineering design, and performance of commercial plants have been given elsewhere." It will be shown that a pure metal can be precipitated by reduction with hydrogen from solutions obtained by commercial leaching methods when the solution cohposition is controlled and proper acidity, proper metal ion concentration through controlled complex formation and hydrolysis, and adequate agitation for suspension of metal and for transfer of reducing gas are maintained. Reasonable temperatures and pressures are used which are less excessive than those used by previous workers, although they are maintained at above equilibrium values because of process kinetics.' It has also been found necessary to induce nuclea-tion and to control growth and agglomeration in order to get a powder product of suitable physical properties. Review of the Literature Muller, Schlecht, and Schubardt of I. G. Farbenm claimed a successive reduction of silver, copper, nickel, cobalt, and zinc from ammoniacal solution by applying progressively higher temperatures and hydrogen pressures. Metals produced by this technique were not pure, since no attempt was made to adjust the solution composition between the different reductions. It is doubtful that the zinc product contained any metallic zinc. The major contribution to the literature" was made by the Ipatiews,12 who prepared platinum, iridium, copper, nickel, cobalt, lead, tin, arsenic. antimony, and bismuth at often extreme conditions, up to the critical temperature of water (373"C), at 1500 to 7500 psi, for as long as several days. Even cadmium and zinc were claimed to have been observed in trace quantities precipitated together with basic salts. In the early experiments solutions were not stirred. Extensive formation of oxides and basic salts occurred. probably long before sufficient hydrogen could be supplied in the unstirred liquid to decrease the metal concentration in solution by reduction. The importance of hydrogen pressure was

Jan 1, 1957

By Manochehr Oliazadeh

"Water shortage becomes a major challenge in mining industry. The best example is Chile where the Chilean authorities declared a state of emergency in 2012. Depletion of high grade ore-bodies necessitates the use of low grade ores. If the demand for metals remains constant, more low-grade ores need to be mined to produce the same tonnages of metals. This increases the water demand in mining industry. Mining industry competes with other industries such as agriculture and manufacturing. Agriculture and manufacturing consume 1500 and 2300 billion m3 water respectively. The global use is 4500 billion m3 while the mining uses 80 billion m3 of water per annum.To tackle the water challenges in mining industry and also avoid competing with other users for fresh water, many efforts have been made, including using lower quality waters to reduce the fresh water consumption in ore processing. Saline water or hyper saline water from seas or the ground is accessible; however the cost of desalination is remarkable. Desalination plants and associated pipelines and pumps capital cost can easily exceed $ 500 million. Saline water will certainly increase the operating costs due to high wear rate of mechanical equipment but at current situation of mining industry spending all this money upfront does not look attractive. Desalination leaves salt on land at mine site which may create environmental issues.Dry processing can be a solution for water shortage in mineral processing. Wet processes dispose tailings on land with little or no agricultural productivity. It also may contaminate surface and ground water and generate dust. This paper reviews the water consumption by various mineral commodities, discuss briefly about recent of application of salt water in mineral processes and finally discuss about dry processes as alternative solution for water shortage in mining industry."

Jan 1, 2014

In this study, we develop a detailed model of the likely future carbon footprint of primary copper supply. We develop a peak copper production model, based on a detailed copper resource data set, and combine this with a comprehensive life cycle assessment model of copper mining and milling to predict greenhouse gas emission rates and intensities of Australian and global copper production up to 2100. By establishing a quantitative prediction of both copper production and corresponding greenhouse gas emissions of Australian and global copper industry, we then analysed the emissions intensity of various energy input scenarios, such as business-as-usual, solar thermal electricity and solar thermal electricity with biodiesel. The Australian Government has an aspirational goal for long-term greenhouse gas emissions of an 80% reduction from the 2000 level by 2050. For the copper sector, this means moving from about 12.6 Mt CO2e in 2000 to a goal of some 2.52 Mt CO2e in 2050 (assuming equal emissions reductions across the economy). Based on the energy sources modelled, only the solar thermal plus biodiesel scenario was capable of achieving this goal at about 0.15 Mt CO2e, since the solar thermal alone scenario still includes normal petro-diesel as a major source of emissions. Overall, it is clear that there are abundant resources which can meet expected long-term copper demands, the critical issue is more the carbon (and environmental) footprint of different copper supplies and use rather than how much is available for mining. It is clear that the switch to renewable energy can have a profound impact on the carbon intensity of copper supply, even allowing for increased energy intensity as ore grades decline, and a complete conversion to renewable energy will position the copper sector to meet existing annual greenhouse gas emissions targets and goals.

Aug 1, 2013

By R Thompson, J Miedecke, D Handel, E Tomicek, D Tulloch

"The Mine Haul Road Optimisation Alliance (HROA) is a unique Australian industry–academia collaboration that has been developed to support mine haul road operators. The alliance integrates industry, end-user service providers and academic research expertise in mine haul road design, construction and operation to identify, quantify, implement and monitor the various equipment, materials and road management strategies and solutions required to drive haulage productivity improvements.Initially, a broad overview of the university–industry collaborative landscape is presented, following which the current situation in the Australian mining sector is reviewed both nationally, and on a country-wide basis internationally. This insight places into context the opportunity that strategic collaborations present, to drive productivity and efficiency in mining, while also delivering innovative technology solutions.Following an overview of the HROA collaborative structure, aims and objectives, it is shown how academia and industry collaborations can deliver a more robust and needs-driven solution to mine haul road design, performance and management, especially where integrated solutions are needed. Critically in this approach, implementation and monitoring data provided by industry and service providers alike form the foundation on which to develop research knowledge and innovation that is more responsive to the end-user requirements, typically represented by ‘early goals’ and practical, implementable solutions.The paper concludes with examples of how the alliance collaborations work in practice to deliver focused mine haul road research outcomes, together with the mechanisms used to ensure industry needs are met through end-user driven research solutions for enhanced operational performance.Citation:Handel, D, Miedecke, J, Thompson, R, Tomicek, E and Tulloch, D, 2016. Driving Haulage Productivity Improvements through Industry–Academia Collaboration, in Proceedings Ninth AusIMM Open Pit Operators' Conference 2016, pp 243–252 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 15, 2016

By Seksak Asavavisithchai, Natthida Jareankieathbovorn, Areeya Srichaiyaperk

"Recycling of ADC12 alloy scraps for fabrication of open-cell aluminium foams has been conducted via pressure infiltration method of replication process. The scrap, up to 50 wt.%, was melted with pure aluminium billet, followed by infiltration in a replicated mold of polyethylene foam structure. Compared with the pure aluminium foam, the compressive strength and hardness are higher for the foams with recycled scraps. The increase in foam mechanical properties is due to the presence of Si hard phase in Al matrix. The strength and hardness of the foams also increase with increasing contents of the scraps.IntroductionRecently, open-cell metallic foams have been brought to considerable attention of many industries due to their superior properties; such as large surface area, high specific strength, thermal conductivity, high service temperature and excellent anti-microbial activity, that cannot be found in conventional materials [1, 2]. Typically, open-cell foams are used in functional applications for which a requirement of high strength materials is not demanded. Good examples of such applications include heat exchangers, bone-replacement implants, interconnects, catalyst supports, and sound insulators.Among all types of open-cell metallic foams, aluminium (Al) is the most widely used base metal, due to low material cost, low density, low melting temperature and good corrosion resistance. To improve mechanical properties of Al foam, modification of foam microstructure with addition of alloy elements or ceramic particles is commonly carried out [3, 4]. ADC12 alloy is a typical die-casting Al alloy with high content of silicon (Si) close to the eutectic point in Al-Si binary phase diagram. The alloy is extensively used in the casting industry, due to high wear and corrosion resistance, low coefficient of thermal expansion and excellent castability [5]. The mechanical properties of Al-Si alloy are strongly dependent of Si content."

Jan 1, 2012

By John C. Machisak

THE INJURY data and experience at quarries and related plants of the United States are presented in this publication under the following general sections (A) General injury experience: Tables 1-3: Current data on number of injuries, injury-frequency rates, location, accident agency, degree of injury, and related employment data. (B) Injury experience at different kinds of quarries: Tables 4-5: Current data on number of injuries, injury-frequency rates, location, accident agency, degree of injury, and related employment, data. (C) Injury experience by States: Tables 6-20: Current data on the number of injuries, injury-frequency rates, accident agency, degree of injury, and related employment data. (D) Selected injury data: Tables 21-30: Current data on various selected factors of operating conditions at different kinds of quarries, including employment size-groups, length of shifts, comparative severity of injuries, and injury data and related employment experience at dimension-stone and nondimension-stone quarries and at underground quarries. (E) Historical injury experience: Table 31: Injury and employment data on the quarrying industry for 1911 through 1957. Statistical data on injuries and related employment in the quarrying industries have been collected annually from the operating companies since 1911. Reporting to the Bureau of Mines is voluntary; there is no Federal law compelling operators of quarries and related plants to supply such data. Data presented herein may not be complete for the entire industry. They are however, believed to be representative of the hazards common to all quarry and related workers. Moreover, the figures are comparable as between States-a significant fact in view of the lack of uniformity among the States with regard to the classes of injuries covered by State reports and other factors that tend to make it impracticable or impossible when using State records to

Jan 1, 1960

By G J. Showers, P Botman, A G. Hunt

Iron Road Limited (Iron Road) is currently evaluating the feasibility of producing 21.5 Mt/a of high-grade (>66 per cent Fe) magnetite concentrate from a 3.7 Bt resource (JORC) located at Warramboo on the central Eyre Peninsula in South Australia. Bulk concentrate can be produced via a conventional grind and low-intensity magnetic separation flow sheet. Due to the comparatively coarse magnetite liberation size (106 µm), consideration was given to enhancing both the grind economics and coarser product sizing via gravity separation.This paper outlines the test work, flow sheet design and engineering design of a gravity beneficiation circuit (GBC) conducted by Mineral Technologies for Iron Road. The resulting circuit optimisation necessitated mass balance simulation by Iron Road’s SysCAD model to quantify the resulting changes in mill recirculation load. This included the determination of project-critical grinding power and energy requirements with and without the GBC installed into the primary ball mill classification circuit. The outcome of this work was the design of a GBC, including spirals and up-current classification, which led to a substantial reduction (33 per cent) in ball mill recirculating load and power requirements, together with a favourable coarsening of final product size due to the relatively coarser gravity concentrate. This has led to a significant reduction in project design capital and operating costs. A further benefit of this approach is increased recovery of (paramagnetic) hematite and lesser titano-hematite via gravity separation compared to an all-magnetic separation approach.CITATION:Hunt, A G, Showers, G J and Botman, P, 2015. Test work and design of a gravity circuit for Iron Road’s Central Eyre Iron Project, in Proceedings Iron Ore 2015, pp 139–142 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015