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Gold was determined directly in eight different mill cyanide solutions, by atomic absorption spectroscopy in an acetylene-air flame. Some of the mill solutions were diluted with water to bring them into the most sensitive absorption region (5-50 p.p.m. Au) whereas those solutions with very low gold content «2 p.p.m.) were concentrated by evaporation.Calcium was complexed with ethylene diamine tetra-acetic acid (EDTA) to avoid the undesirable effect of a precipitate on atomization.When added to standard gold solutions, EDTA had no effect on absorption, nor did any of the impurities common in mill cyanide solutions.Known amounts of gold, ranging from 2 to 30 p.p.m., were added to mill solution'aliquots and recovered to within 100 ± 2·5 per cent. For duplicate determinations under normal worKing conditions, standard deviation was 1·32 p.p.m.Excellent agreement was found between atomic absorption gold values and accurate fire assay values.INTRODUCTIONAtomic absorption spectroscopy has been shown to offer a rapid and accurate method for the determination of trace amounts of a number of metal ions. In the field of primary metallurgy atomic adsorption has been used for routine determinations of lead, copper, silver, zinc, cadmium and iron in a variety of raw materials and intermediate products.The scope of atomic absorption spectroscopy was reviewed recently by Willis (1963).The noble metals silver, gold, platinum, rhodium and palladium were determined by atomic absorption from chloride solutions by Lockyer ·and Hames (1959). In their determination of gold down to 1 p.p.m., they found no interference from the noble metals, nor from considerable excess...

Jan 1, 1964

Hot briquetting is a reliable, fully developed industrial concept for the passivation of direct reduced iron produced with the various processes of direct reduction. During hot briquetting, the large specific surface area of direct reduced iron is drastically reduced, and therefore the well-known problems caused by reoxidation and overheating are avoided. Even the shipping instructions published by the International Maritime Organisation (IMO) confirm that Hot Briquetted Iron (HBI) can be handled and shipped without special precautions. From the mid-1970s until today, after extensive pilot testing of the technology, a number of industrial plants for the hot briquetting of direct reduced iron have gone into operation. Additional hot briquetting plants for already established but also for new direct reduction processes are tinder construction or in different stages of planning. This paper describes the characteristics of HBI and its current industrial application for various Direct Reduction Processes.

Jan 1, 1999

By Peter Swanson

A seismic monitoring network has been installed in western Colorado (USA) in the vicinity of three underground coal mines to (i) distinguish and characterize seismic activity as either mining related or naturally occurring, (ii) implement a real-time event monitoring and notification tool, and (iii) collect data for use in research studies aimed at quantifying impacts from mining-related and natural seismicity. These potential impacts include dynamic rock mass failures such as coal bumps as well as strong shaking in the vicinity of critical structures such as impoundment dams, reservoirs, mine seals, mine openings, and steep slopes. Examples of two damaging seismic events are presented and the mining and geologic factors attending these dynamic failures are described.

Jan 1, 2008

By B. Leong, H. Joubert

Keywords: Pyrometallurgy, furnace, auxiliary equipment, copper slag launders Pyromet has designed copper launders for tapping slag. What makes Pyromet?s launder design innovative and safe is that it does not have any cooling water channels underneath the launder runner, whilst achieving effective cooling of the runner. If matte burn-throughs were to occur through the launder runner, the risk of damaging water channels and the risk of explosions are reduced. In addition, since the cooling water channels are not harmed, the launder is easily repairable and reusable. Pyromet makes use of Finite Element Analysis to optimize the launder geometry to ensure that sufficient energy is removed from the centre of the launder. Factors considered during the launder design include the suitability of the geometry to the client?s needs, experience from existing installations, and ease of fabrication. Pyromet goes so far as to develop procedures for fabricators to ensure that fabrication issues do not compromise the functionality of the launder. When launder orders are received by Pyromet, the entire fabrication process and the functioning of the launders during operations are monitored to ensure that the launder designs are continuously improving with every installation.

Jan 1, 2006

Further evidence is presented as to the widespread occurrence of Thiobacillus ferrooxidans in nature in association with sulphide minerals. Leaching rates are discussed in terms of the effect of environmental parameters, particularly Eh and pH, on the bacterial process.The methods used to investigate leaching phenomena are described and the advantages and limitations of each method are discussed. A theoretical treatment of the bacterial leaching process is given which indicates that the optimum conditions arrived at by traditional methods are compatible with those deduced from consideration of the mathematics of continuous culture and thermodynamics

Jan 1, 1968

By Tapan Goswami

The expectation from the blasting engineers and shotfirers is often that explosives will perform optimally at all times. However, in reality, non-ideal situations exist on mine sites and occurrences of poor explosives performance are common. Often the cause is difficult to identify. Having a good application technique and analysis skills will minimise the risk of poor performance. This paper will discuss the experiences gained by the author while blasting in the Hunter Valley, Australia.

Jan 1, 2003

By Sutham Niyomwas

The Fe-TiC composite powder was synthesized in situ by carbothermal reduction of ilmenite. The standard Gibbs energy minimization method was used to calculate the equilibrium composition of the reacting species. The effects of the reaction temperature (1300 °C - 1500°C) and milling time of precursors on the Fe-TiC conversion and powder morphologies were investigated using XRD and SEM method. The synthesized products showed that composite with iron matrix and titanium carbide as a reinforced phase was formed.

Jan 1, 2006

By R. C. D. Phillis

The management of critical resource inventories is an important productivity lever and a significant risk factor?risk in the sense that poor resource availability lends itself to disempowerment of workers, unsafe work practices, wasted spending (high unit costs),and poor quality of work (including mining waste/rework). Most underground platinum mines experience lost blasts that directly lead to reduced productivity. In most surveyed shafts, 30% of lost blasts can be attributed to shortages of critical material and/or equipment. The problem is prevalent despite the existence of conventional transitory surface and underground stores. This paper discusses the introduction of buffer stores as a complementary materials storage system in order to improve health and safety in mines as well as reduce lost blasts. Both quantitative and qualitative results have shown that buffer stores result in dramatic improvements in productivity and are readily acceptable by stakeholders. Keywords Buffer stores, lost blast.

Jan 1, 2011

By A Giblett, R Dunne, D Appelhans

There are a number of hurdles that must be negotiated in order to design an effective gold ore treatment facility such that the expectations forming the basis of project economics are valid and can be achieved in practice. Selecting samples based on geometallurgical context, performing and interpreting testwork relevant to the selected process flowsheet are essential considerations towards achieving this aim. This paper discusses recent experiences in process development for free milling gold ores giving consideration to frequently encountered challenges of this nature.CITATION:Giblett, A, Appelhans, D and Dunne, R, 2013. Considerations for effective gold process development, in Proceedings MetPlant 2013 , pp 445-454 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By Keith R. Vining

Solid fuel, usually coke or anthracite, is commonly added to ground iron ore fines in the pelletising process to reduce the amount of burner fuel required and the maximum firing temperature, while maintaining pellet strength and the productivity of the pelletising plant. However, the use of coke and coal contribute to the production of greenhouse gases (eg carbon dioxide) and are a source of NOx and SOx emissions. Utilising wood biomass / wood char is one methodology CSIRO Minerals is investigating as an alternative to coke and coal, as it is a renewable energy source that is very reactive, has a low ash content and the potential to reduce emissions of greenhouse gases from the iron and steel-making process. Previous work has established that charcoal can effectively replace coke in the sintering process (Lovel et al, 2005), and the following experimental work aims to demonstrate that it can also provide an adequate replacement for coke and coal in the pelletising process. The paper presents the results of an experimental testwork program comparing the behaviour of fired pellets containing traditional solid fuels and charcoal. The physical properties of the pellets are compared in terms of their compressive strength, tumble and abrasion indices and the reduction properties. A qualitative assessment of the pellet microstructures is also presented.

May 1, 2007

By E. Baliktsis

We have searched and analyzed several modern technologies aiming at the best applications of environmental management, the studying of quarrying ? mining as well as the excavation sites ? utilization ? rehabilitation. We have used long-range reflectorless laser surveying systems, so as to achieve the fastest and most accurate surveying of the extractive work sites. We also used them, in order to collect field data, measure distances, surveying monitoring stations and environmental parameters ? data. Furthermore these systems can make the field work quite faster, more reliable and credible and have low cost in collecting data even in dangerous and non-approachable areas. We have used and processed on the field data in G.I.S. applications, in order to create 2-D and 3-D digital ground models. These G.I.S. applications present the existing relief and the management of the final stage of the area. The suggested techniques and works needed, for reclamation and utilization of the areas, could be tried, evaluated and well presented. The evolution and utilization of these ?smart? modern tools for the effective environmental management of quarrying ? mining ? extractive activity sites, will be presented by using case histories from the Hellenic territory.

Jan 1, 2002

By Ron Bromenschenkel

The State of California, Department of Transportation is currently retrofitting a major interchange near the San Francisco area. The project is located in a highly traveled area of Oakland with light rail commuter service near many footings. Over 600 micropiles are being used in conjunction with CIDH piles for footing stabilization. A specially designed Soil Nail pile will support footings for a new light rail utility structure. Pile testing features in this contract serve as points of interest for future foundation designs. The presentation focuses on substructure issues of this incterchange retrofit. Both design and construction considerations will be covered. Design Considerations: ? Project Description ? Structure inadequacies ? Design criteria ? Design contraints ? Retrofit strategy ? Consultant analysis ? Pile Designs and Test Sites ? Contract Specifications ? Construction Plan and Cost

Jan 1, 1998

By J. R. Ross

A reconnaissance for sources of scandium and a metallurgical investigation of recovery methods for byproduct scandium from uranium mill solutions were conducted by the Bureau of Mines. The work on scandium was undertaken to obtain information on domestic resources and to explore and develop recovery procedures in consonance with the Bureau's long-range program for conservation and wise utilization of mineral resources. The element scandium is widely distributed in the earth's crust in trace amounts, but it seldom occurs as an important constituent in any mineral. An exception is thortveitite, (Sc,Y)2 Si207) a rare mineral that contains various amounts of scandium and yttrium and may contain up to 42 percent scandium oxide (SC203). Knowledge of the chemistry of scandium has expanded rapidly in recent years (1, 4, 9)4 but only fragmentary information is available about the metal because it is still largely a laboratory curiosity without established uses (2, 3). A recent study shows some of the physical proper-ties of the metal are (1) density of 3.05 grams per cubic centimeter) (2) melting point of 1,540° C, (3) hexagonal close-packed structure) (4) hardness of about 50 Brinell (500-kilogram load), and (5) an alloy behavior similar to yttrium and rare-earth metals (2). The price of $2,850 a pound for scandium oxide of 99.9 percent purity and $2,700 a pound for oxide of 99 percent purity reflects the scarcity and complex chemistry of the element.

Jan 1, 1962

By Heithecker R. E.

In June 1933 the Bureau of Mines, in cooperation with the State of Oklahoma and the Oklahoma City Chamber of Commerce,, published a report of the gas reserves in the Oklahoma City oil field3/ based upon data as of October 1932, at which time there were 43 classified gas wells in the field, The estimates were obtained by the ?porosity-area" method. There are two general methods of estimating natural-gas reserves. The porosity-area method, as used by Hill and Rawlins, is used when a gas field is comparatively new but after enough drilling has been done to determine the average thickness, porosity, and areal extent of the producing horizon. The "pressure-volume? method of estimating gas reserves, the method used in this report, may be used after a sufficient volume of gas has bean withdrawn from the reservoir to cause an appreciable decline in reservoir pressure.

Jan 1, 1937

By J. B. Czirr

MESA Corporation has completed a four-year program for the Bureau of Mines to develop a technique for measuring roof competence in underground coal mines. The preferred technique employs a tracer gas that is injected into a roof borehole drilled near the working face. The tracer gas performs the dual purpose of determining the pressure loss rate from the borehole and of marking the diffusion pattern of the the escaping gas. The primary detection technique relies upon observation of the rate of pressure drop in a hole drilled in the roof strata under test. If this measurement indicates a significant probability of roof collapse, the gas diffusion pattern is outlined with the Leak-gun tracer-gas detector. These two techniques provide a comprehensive method for predicting the relative probability of roof collapse in operating coal mines.

Jan 1, 1985

By Yunyan Wang

Diagrams of pc-pH for the complex ions concentration and pH value and -g- for activity coefficient and ionic strength ln±MnSOI4had been drew based on the thermodynamic principle of coordination chemistry and combined with Pitzer theory at 298.15K. The diagram of -g- indicated that -gincreased sharply from 0.0000 up to 1.2147 when I changed from 0.00 ln±MnSOIln4±MnSO4to 0.09; The increase of -gbecame slowly when I was more than 1.00 and less than 1.69; kept still when I ln±MnSOln4-g±MnSO4was more than 2.25 and less than 4.00. Diagrams of pc-pH illustrated that the minimum solubility of Mn(OH)2(s) increased with the increase of I, the pc increased from 6.5 to 5.5 when I increased from 0.00 to 4.00; The pH of the minimum solubility of Mn(OH)2(s) increased with the increase of I, the pH increased from 11.80 to 12.76 when I increased from 0.00 to 2.89, the pH kept still when I (I was less than 4.0) increased. There is single function relationship between the minimum solubility of Mn(OH)2(s) and relevant pH in different I.

Jan 1, 2010

By R. E. Heithecker

In June 1933 the Bureau of Mines, in cooperation with the State of Oklahoma and the Oklahoma City Chamber of Commerce, published a report of the gas at reserves in the Oklahoma City oil field3/ based upon data as of October 1932, at which time there were 43 classified gas wells in the field, The estimates were obtained by the ?porosity-area" method. There are two general methods of estimating natural-gas reserves. The porosity-area method, as used by Hill and Rawlins, is used when a gas field is comparatively new but after enough drilling has been done to determine the average thickness, porosity, and areal extent of the producing horizon. The "pressure-volume? method of estimating gas reserves, the method used in this report, nay be used after a sufficient volume of gas has bean withdrawn from the reservoir to cause an appreciable decline in reservoir pressure.

Jan 1, 1937

By James W. Reil, Douglas A. Anderson, Steven L. Burchell

A total of 26 full-scale production blasts at three sites were extensively monitored with sophisticated instrumentation systems to determine the benefits of "ore. accurate detonators. The new and "ore accurate MS electric Masterdet detonator was tested against conventional detonators to determine any increase in productivity outputs. All blast design parameters between paired blasts were kept as constant as possible with the only difference being the inherent accuracy of both detonator systems.

Jan 1, 1989

By Robert V. Berryhill

Reconnaissance studies of beach deposits along approximately 220 miles of the shoreline of Bristol Bay, Alaska, were made to determine if more detailed investigations were warranted. In addition to preliminary mapping of the deposits, samples were obtained from auger borings spaced at 1-mile intervals in key areas; shovel samples were collected to supplement the borings. Most samples were roughly concentrated in the field; magnetic separation tests, petrographic analyses, and determinations for radiometric equivalent uranium, gold, platinum, iron, and titanium were made in the Bureau of Mines laboratory at Juneau, Alaska. Spot samples from some beaches along the shores of the Alaska Peninsula indicate small deposits containing up to 10 percent recoverable titaniferous magnetite; some larger deposits were indicated to contain from 1 to 2 percent total heavy metal, principally as titaniferous magnetite. Significant amounts of other commercial minerals were not detected.

Jan 1, 1963

By M. S. Safarzadeh

Over the last fifty years, the treatment of enargite concentrates has not received much attention primarily because of the availability of other clean concentrates suitable for processing with existing smelting and/or leaching technologies. As traditional copper ores have become scarcer, copper-arsenic ore deposits have garnered more interest. Arsenic release is a significant concern during the treatment of enargite by pyro or hydrometallurgical methods. Enargite is also very refractive in standard leaching procedures. Thus, economical treatment options for enargite concentrates are needed. Preliminary experiments have shown that the acid-bake leach process could be adapted and used for the treatment of enargite concentrates. In this study, low-temperature (100-400 ºC) sulfuric acid baking of an enargite concentrate followed by water-leaching has been evaluated. The results indicate the thermal transformation of enargite to copper sulfate during sulfuric acid baking, with most of the arsenic being released from the concentrate into the gas phase for baking at 400 ºC. The condition for maximum copper extraction (~100%) from the concentrate was found to be 400 ºC, sulfuric acid amount of 0.5 mL/g of concentrate, and 2 h baking time. Part of the arsenic was captured in the form of arsenopyrite (FeAsS). XRD analysis proved the presence of some arsenic in the form of claudetite (As2O3) in the baked concentrate. Acid baking of pure enargite behaved in similar fashion.

Jan 1, 2012