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By D. M. Hausen

Microscopic point-counting of polished sections, in combination with x-ray diffraction analyses of representative whole rock samples, provides an efficient means to compare the modal mineralogic composition of different rock types. Major gangue minerals, e.g., quartz, feldspars, micas, amphiboles, chlorite, clays, etc., are estimated semiquantitatively by x-ray diffraction techniques, utilizing optimum grind, gridded sample surfaces and a sample spinner during scanning. Opaque to semi-opaque oxide and .sulfide phases are estimated by microscopic "point-count" and "gross-count" scanning. Total mineralogic compositions are calculated and normalized to 100 percent from XRD and microscopic data by computer programming. Comparative mineral analyses for different rock types, as well as quantitative microscopic data for various parameters, including particle and crystal sizes, textures, degree of alteration, paragenesis, etc., provide useful guides in mineral exploration, both in early stages of geologic mapping and later stages of economic evaluation. Several case histories are described.

Jan 1, 1981

By S. Krishnannair

Singular Spectrum Analysis (SSA) is an effective data-adaptive multimodal tool for monitoring chemical processes. However, monitoring multiscale signals using principal component analysis obtained from the multilevel decomposition of process signals using basic SSA assume the upper control limits of monitoring charts (" ) to have a Gaussian distribution. This assumption deteriorates the performance of basic SSA when applied to the monitoring of nonlinear processes. To address the issue in this paper, the kernel density estimation (KDE) was used to estimate upper control limits of monitoring charts for basic SSA based nonlinear process monitoring techniques. The monitoring performance of the resulting basic SSA-KDE approach was then compared with a basic SSA approach of which upper control limits of the monitoring charts were determined based on a Gaussian distribution. Application on nonlinear dynamic simulated process and base metal flotation plant chemical processes showed that the SSA-KDE approach provided better overall performance than the SSA approach with Gaussian assumption-based upper control limits for its monitoring charts. Keywords: Fault detection, singular value decomposition, singular spectrum analysis, kernel density estimation

Jan 1, 2020

By Charles W. Frey

OF all the machinery used in mining work, mine cars are probably the most abused. They are hauled through water and muck, up hill and down grade, whipped around curves, bumped and jerked, and exposed to the ravages of the weather. However, as a general rule their lubrication is not altogether neglected. The mine operator may not heed the extra drag that a frozen conveyor bearing gives, but he is all too aware of the increased load that faulty mine car wheels put on his power plant. When the circuit breakers begin to fly, and when his mine loco- motives come out with only half the cars that they were able to carry a month before, then neglected mine car wheel lubrication becomes apparent, and woe to the person responsible.

Jan 1, 1938

By Oliver Bowles

WAR necessities have spurred inventive genius in many fields. A grinding mill without any moving grinding parts stirs the imagination. Among the new and striking accomplishments in the heterogeneous group of nonmetallic industrial minerals is the use of an electric arc to speed up manyfold the difficult and delicate task of drilling a microscopic hole in a diamond, the hardest of all known substances. Outstanding in the field of optical research is the ability that man has developed to improve upon nature by making in the laboratory optical crystals many times larger than those usually found in rocky crevices. These are merely samples of numerous events and circumstances of noteworthy import, many of which are recorded in this review. Termination of the second World War in 1945 permits an appraisal of the effects of the conflict and the probable effects of the coming restoration of a peacetime economy on the nonmetallic mineral industries. Some industries were stimulated greatly by the war, notably mica, quartz crystal, graphite, spinning asbestos, potash, fluorspar, barite, and refractories. The large-tonnage industries connected with the building trades, however, were forced to curtail their activities, except where their products were needed for wartime construction. Their reconversion to peacetime production will not be difficult.

Jan 1, 1946

By J. E. Harris

The metallic elements, beryllium, calcium, cerium, lithium, manganese, titanium, vanadium and zirconium are used in metallurgical practice in relatively small percentages for the purpose of improving the physical properties of various alloys. No important uses for any of these elements have thus far been developed either in the pure form or in alloys of which they constitute the major constituent.

Jan 1, 1935

By George T. Wickes

(Washington Meeting, May, 1905.) SEVERAL years ago, Mr. Robert A. Cook described and illustrated in our Transactions 1 a mechanical coke-drawer, patented in 1891 by Mr. Thomas Smith of the Thorncliff Iron Works, Sheffield, England, and first introduced in the United States in, 1896, at the coking-plant of the Latrobe Coal Co., Latrobe, Pa. This machine has not received any very extended application in this country, although it was successfully used in two places for a number of years. The present. paper describes a new and simpler machine, containing few wearing-parts capable of withstanding continued rough usage. Anything which tends to prolong the general use of bee-hive ovens will be welcome to those who are interested in cheapen¬ing the cost of producing coke in such ovens, especially if it provides satisfactory mechanical means, replacing the hard labor involved in drawing coke by hand with the old-fashioned ?duck bill.? The difficulty of finding efficient coke-drawers, especially during the summer season, and in the South, is notorious. Yet, notwithstanding the great improvements that have been made in retort coke-ovens, new bee-hive ovens are continually constructed; and a machine which will successfully compete with hand-drawing, and, at the same time, add to the efficiency of the bee-hive oven, seems to deserve notice. The machine here described was put in operation at the Frick Coal and Coke Co.'s plant, known as Continental No. 1, at Uniontown, Pa., in October, 1904, and is reported to have met successfully all the tests to which it has been subjected. This trial has demonstrated that one of these machines, equipped with an electric motor, and operated by one mart with an assistant, besides two men to " water down " the

Jul 1, 1905

By G. K. Burgess

J. W. RICHARDS, South Bethlehem, Pa.-I think my affections are still rather with the radiation pyrometer than the optical pyrometer, for practical use, and I wish that Prof. Burgess would use the two together, under the same conditions, using the optical as his standard, if he prefers. Then, assuming the optical emissivity which he feels is correct for the optical pyrometer, he could calculate the thermal emissivity for use with .the radiation pyrometer. If we could thus get reliable values for the thermal emissivity, we could then use the radiation pyrometer, and would avoid the use of the standard lamp, which has to be frequently calibrated for use in the optical pyrometer. It is very advisable to distinguish carefully between the terms optical emissivity and thermal emissivity. There -is considerable confusion caused by the bare statement that molten iron has an emissivity of so much, meaning by that its optical emissivity, for a light wave of a certain length; whereas what we want in the radiation pyrometer is its total ther-

Jan 4, 1917

By Oliver Bowles

[Simple systematic accounting that adequately records all transactions has long been regarded as essential to the welfare of any business enterprise. Some of the defects that detract from the prosperity of the slate industry are attributable to a lack of effectiveness in cost keeping. This condition has promoted the United States Bureau of Mines to make a detailed study of accounting methods for the slate industry, and to present for consideration a system of accounts, which it is believe would enable the industry to attain more economical management and operation if accepted by a fair proportion of its important units. The method of accounting presented herein has been worked out with the assistance of leading slate producers and the recommendations are tentative and are submitted in this form as a means of developing constructive criticism. Believing that cooperative effort in this, as in many ether problems will bring the most enduring benefits to the industry as a whole, the writer urges that the cost earnest consideration be given to this vital problem now facing the slate industry.]

Jan 1, 1929

By LUIS ALBERTO TORRES-CRUZ

The Plewes method is relatively well known among geotechnical engineers interested in assessing the liquefaction potential of soil deposits. Furthermore, it was one of the four methods considered in the post-failure investigation report of the Feijao Dam I, also known as the Brumadinho Dam, in Brazil. The inclusion of the method in that report is likely to increase its visibility among geotechnical practitioners tasked with assessing the liquefaction potential of tailings. While the authors of the method duly presented it as a screening method, more recent technical literature contains conflicting views on its reliability. Considering the popularity of the method and that the safety record of tailings dams is a cause of great concern, this study assessed the uncertainty of results from the Plewes method. The study concludes that, even under optimistic assumptions, the results of the method are too uncertain for detailed characterization of tailings deposits.

The principal activities of the Bureau of Mines Explosives Research Center from July 1, 1963 to June 30, 1964 are described briefly in part 1. Part 2 gives short abstracts of publications that appeared during fiscal year 1964; in general, the research reported in these publications antedates the report period. Part 3 describes a short-term investigation into safety problems associated with shipping of molten sulfur; this investigation is not at present destined for publication elsewhere.

Jan 1, 1965

By R. Boom, Y. V. Meteleva-Fischer, B. Kraaijveld, H. Kuntzel

"Segregation of impurities during refining of metallurgical grade silicon (MG-Si) is an option to produce solar grade silicon (SG-Si). Directional solidification is a last step in production of SG-Si effective for removal of metallic impurities. The possibility is investigated to use metallic impurities originally present in MG-Si for removing boron and phosphorus. MG-Si has been treated using two methods: 1) alloying with calcium and 2) refining with Na2O-CaO-SiO2 slag, both by controlled cooling. The microstructure of silicon and the impurities distribution have been studied before and after the treatments. Using EPMA phosphorus and boron have been detected in 1-2 wt% concentration range in several intermetallic compounds in grain boundaries after both treatments. This observation points to a different possible mechanism of silicon refining from boron and phosphorus. Controlled cooling improves migration of phosphorus and boron to the silicide phases in grain boundaries, which can be removed by acid leaching treatment.2. IntroductionStandards for silicon solar cells and growing demand on “green” energy require economical and efficient route to the production of solar grade silicon. Refining of cheap metallurgical grade silicon is one of the promising options, where application of existing metallurgical approaches can result in cost-efficient production on industrial scale. Focus in refining is on impurities, which are most difficult to remove: B, P, Al, Ti, due to their large segregation coefficient in silicon and low vapour pressure [1]. Moreover, more environmentally friendly technology in comparison to the traditional Siemens process [2] will be in accordance with societal needs. Based on properties of common impurities in metallurgical grade silicon, alloying refining and slag refining are suggested as competitive techniques having potential effect on removal of impurities harmful for conversion of solar energy [3, 4]. Alloying with Ca followed by acid leaching was found to be effective for removal of Fe and Ti from silicon [5] and to enhance also removal of boron [6] and phosphorus [7, 8]. In the work of Inoue et al. [8] drastically increasing removal of phosphorus from silicon has been observed with an increase of Ca content and a thermodynamics-based explanation was provided. Since phosphorus has been found to condense in the secondary precipitate mainly composed of CaSi2, it can be removed together with iron and titanium by consecutive acid leaching treatment. Slag refining is one of the metallurgical methods proposed to be effective for refining of metallurgical grade silicon from boron [9, 10]. Slags with additions of the following oxides to silica have shown positive effect on removal of boron: CaO [11-13], Na2O [11,14]. Mechanism of slag refining from boron is based on oxidation of boron followed by its incorporation in the slag network [9,11]; the same mechanism is suggested for refining from phosphorus taking into account that oxides of boron and phosphorus are known as network-formers [15]."

Jan 1, 2012

By A. L. de Vegt

Hydrogen sulfide is an expensive chemical used in nickel, zinc and copper mining and metallurgical operations for selective recovery and concentration of metals from leach water streams, acid plant blow down streams, refinery electrolyte bleeds and precious metal plant bleeds. Hydrogen sulfide is either produced on site by catalytic reduction of elemental sulfur or transported to the site as liquefied hydrogen sulfide (H2S) or as a sodium sulfide solution (NaHS). Biologically produced hydrogen sulfide has economically very interesting application possibilities in the mining and metallurgical industry. Converting sulfates from waste streams into usable hydrogen sulfide by biological reduction results in operational cost savings in existing lime treatment systems. H2S can be produced biologically for less than $500/ton S. For the past ten years Paques has been engaged in the development and installation of treatment systems based on biotechnological processes to remove sulfur compounds from water, air and gaseous streams. Paques has designed and installed a groundwater treatment system for the Budelco zinc refinery in the Netherlands to remove sulfate and heavy metals. The hydrogen sulfide produced is used for recovery of metals, mainly zinc, from the ground water stream. The system has been operating since May 1992 treating a flow of 5000 m3/d. At Kennecott's Bingham Canyon Utah copper mine a pilot plant started operation in November 1995 to develop the process for selective recovery of copper from leach water using biologically produced hydrogen sulfide from sulfate containing groundwater. Other pilot plants are operated at DOE's Pittsburgh Research Center and at Cominco Research focusing on selective recovery of metals.

Jan 1, 1998

By Andre L. De Vegt

Hydrogen sulfide is an expensive chemical used in nickel, zinc and copper mining and metallurgical operations for selective recovery and concentration of metals, from leach water streams, acid plant blow down streams, refinery electrolyte bleeds and precious metal, plant bleeds. Hydrogen sulfide is either produced on site by catalytic reduction of elemental sulfur or transported to the site as liquefied hydrogen sulfide (H2S) or as a sodium sulfide solution (NaHS) Biologically produced hydrogen sulfide has economically very interesting, application possibilities in the mining and metallurgical industry. Converting sulfates from waste streams into usable hydrogen sulfide by biological reduction results in operational cost savings in existing lime treatment systems. H2S can be produced biologically for less-than $500/ton S. For the past ten years Paques has been engaged in the development and installation of treatment systems based on biotechnological processes to remove sulfur compounds from water, air and gaseous streams. Paques has designed and installed a groundwater treatment system for the Budelco zinc refinery in the Netherlands to remove sulfate and heavy metals. The hydrogen sulfide produced is used for recovery of metals,, mainly zinc, from the ground water stream. The system has been operating since May 1992 treating a flow of 5000 m3/d. At Kennecott's Bingham Canyon Utah copper mine, a pilot plant started operation in November 1995 to develop the process for selective recovery of copper from leach water using biologically produced hydrogen sulfide from sulfate containing groundwater. Other pilot plants are operated at DOE's Pittsburgh Research Center and at Cominco Research focusing on selective recovery of metals.

Jan 1, 1998

By Ronald W. Stingelin

The geology of the roof of the Pittsburgh coal bed was studied and mapped in nine contiguous counties containing the bulk of the remaining reserves of this coal bed in the northern Appalachian Coal Basin. Drill core records from Belmont and Monroe counties, Ohio, Washington and Greene counties Pennsylvania, and Ohio, Marshall, Wetzel, Monongalia, and Marion counties, West Virginia provided the data for twelve computer generated regional geologic variable maps. Four of these geologic variables (overburden thickness, vertical distance to the rider coal, lithology at the five foot horizon above the roof of the mineable Pittsburgh seam, and the number of lithologic changes within the 30 foot interval above the roof of the mineable Pittsburgh seam) were used to estimate the risk of potential roof falls by a methological scheme developed during this study. A hazard zone risk map was developed showing a generalized regional trend of increasing risk from west to east across the basin. Mapping of individual geologic variables and mapping of hazard risk can be done at any scale. The accuracy of the mapping is primarily dependent on the density of the drill core records. Geologic feature maps and the hazard risk map contained in this report are reduced (1 :500,000 scale) versions of the larger scale (1 :62,500) maps prepared for the Bureau of Mines as map folios.

Jan 1, 1979

By S. R. Steinacker, H. Schnideritsch, J. Antrekowitsch

Primary copper industry flue dust plays an increasingly important role in the creation of matte and slag. From a thermodynamic point of view, the chemically formed section of fine particles play a techno-logically interesting role in comparison to the mechanical carry-over. Here, the volatilization and the sub-sequent condensation in the off gas system lead to a characteristic distribution of the contained elements which are represented by various compounds of desired metals like zinc and lead. On the contrary, certain undesired components such as arsenic, bismuth and cadmium accumulate within the product as well. This paper describes existing models and theories concerning the formation of flue dust in the copper smelting process and presents a thorough investigation of the physico-chemical fundamentals by verifying assump-tions with thermodynamic calculations. By fully understanding the formation patterns at different stages and temperatures within the process, better knowledge for flue dust in the first step of the pyrometallurgi-cal copper smelting can be obtained - hence leading to new ideas and incentives for the following stages in the copper production cycle.

Jan 1, 2015

By A. A. McDonald

Anode casting has been in operation for two years in Hudson Bay Mining and Smelting's Flin Flon smelter. The new plant allows all casting to be done on one shift and so achieves considerable labour savings. The equipment and operations are described. Some important features are as follows: very consistent anode weights by the use of the load-cell controlled casting ladle; excellent mould life ; very low reject rate; and trouble-free take -off tower. Some of the start-up problems are described and an outline is given of the main operator functions. Data on labour, propane and maintenance costs are presented.

Jan 1, 1977

By R. F. Zaffarano

Intergrated energy balances and energy flows were constructed and quantified for State, regional, and national levels from four separate supply and demand commodity balances for coal, dry natural gas, petroleum and natural gas liquids, and utility electricity. These commodity balances were integrated by source and sectors through conversion and aggregation of their components to energy equivalents expressed in British thermal units (Btu). A summarization of the total gross energy components of supply and demand for commercial energy derived from direct fuels, hydropower and nuclear power, based on individual States and regions, is tabulated for 1960 and 1965. Pertinent computerization details and more than 500 individual State and regional printout tables, in both original commodity units and Btu's, are shown. Using these data, energy flows between States and regions were calculated to identify surplus and deficit energy areas. Report emphasis is on the conceptual aspects of integrated energy balances, rather than on the development of missing State energy data.

Jan 1, 1969

By Finch. J. A., C. Perez, J. M. Ortiz, G. Cortes, A. B. Yañiez, F. Coddou, P. Morales, H. Elgueta

A campaign to perform characterization tests in a TankCell®-300 flotation cell installed at Chuquicamata Codelco's concentrator was conducted. The campaign included integrated gas dispersion measurements (gas velocity radial mapping and single point gas holdup and bubble size) and determination of frother concentration. Cell streams were sampled to assess metallurgical performance at the same time. The experimental program was designed to establish the bubble surface area flux operating range and its effect on performance, and the effect of using longer residence times and of a device designed to enhance mixing in the collection zone (FlowBooster(TM)). The gas dispersion results and their relationship to metallurgical performance are discussed.

Jan 1, 2009

By M Uceda, E Guerra, Y Choi, J L. Shepherd

In this paper we describe the leaching characteristics of pure gold in thiosulfate solutions that contain a known chelator; meso-2,3-dimercaptosuccinic acid (DMSA). The interfacial and chemical characterisation of the system was accomplished using both electrochemical methods and inductively coupled plasma mass spectrometry (ICP-MS) analysis after pure gold samples were exposed to solutions composed of 65 mM Na2S2O3, 1 mM NaOH and a range of DMSA concentrations. In the absence of DMSA, cyclic voltammetry revealed the onset of thiosulfate mediated gold dissolution, the degree of which was reduced at more positive potentials due to the formation of oxidised thiosulfate products on the gold surface. The addition of small amounts of DMSA (<10 ¦M) to the electrolyte resulted in minor changes to the voltammograms indicating a subtle interaction of the additive with the gold surface that may improve leaching. However, at higher concentrations of DMSA (up to 100 ¦M), electrochemical evidence suggests the formation of new oxidation products in solution as well as the formation of more compact monolayers of DMSA on the surface, which contribute to partial repassivation of the surface. The influence of DMSA on thiosulfate leaching of pure gold electrodes at the open circuit potential for a period of 90 minutes was tested and the corresponding gold leaching performance evaluated with ICP-MS analysis. Our data shows that small amounts of DMSA (1 ¦M) doubled the amount of total gold in solution when compared to the same study in the absence of the additive. However, higher concentrations (5 ¦M DMSA) reduced the overall amount of dissolved gold. These results may point to a mechanism where small amounts of DMSA improve leaching by adsorbing onto the surface in a highly defective monolayer that partially blocks or disrupts the formation of passivation products caused by thiosulfate oxidation, but excess DMSA can limit the leaching process itself by forming too coherent a monolayer on the gold surface.CITATION:Uceda, M, Choi, Y, Shepherd, J L and Guerra, E, 2013. Investigating the influence of meso-2,3-dimercaptosuccinic acid on thiosulfate leaching of bulk gold electrodes, in Proceedings World Gold 2013 , pp 207-214 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

This manual provides instructions for installling, operating, and maintaining protective canopies on the Joy Mfg. Co. cutter. These instructions are based upon two actual installations: one made in a mine and one in the factory. The parts list and engineering drawings for the protective canopies are included at the end of the manual. And a discussion of some alternative design concepts is also included. The manual can also be used for retrofitting other cutters with similar protective canopies. Skilled mechanics can determine if the instructions herein would be applicable to the other cutters and can determine any necessary modifications if they are not.

Jan 1, 1973