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By C. Lupi

The electrorefining of primary copper is a well known technology: in this work copper scrap was directly processed in the same way. he copper and copper alloy scrap was previously pressed by means of a 20 tons apparatus in order to avoid pyrometallurgical operations. The samples obtained in this manner showed a good compactness so that they were used as anodes in the electrorefining tests. The tests were carried out on anodes made by copper scrap, copper alloy scrap and a mixture of the two. The electrorefining tests were performed at both 303 and 333 K, in a perspex cell having a volume of 500 ml using a current density of 250 A/m2. The cathode used was always a sheet of pure copper and the electrolyte composition was 40-50 g/l Cu as CuS04 and 150-200 g/l H2SO4. Current efficiency in the range of 92-97% and specific energy consumption ranging from 0.14- 0.20 kWg of copper were reached in all the tests. The refined copper deposits were analyzed by AAS to verify their purity and observed by SEM to highlight their morphology.

Jan 1, 1998

By S. Pollak, J. Rickard

The Long Baseline Neutrino Facility Far Site in Lead, South Dakota is currently under construction and involves drill and blast excavation of the largest and deepest caverns in North America. This paper will review how the geotechnical risks are being managed through careful consideration of excavation sequence, completion of exploratory pilot tunnels, implementation of a robust instrumentation and monitoring program, and validation against the design. Aside from having a cross section of 5,900 square feet and being situated at a depth of one mile, the caverns also employ a unique permanent rock bolt solution which underwent a significant pre-production pull testing program involving varying installation methods and being subject to blast vibrations. The behavior of the schistose rock mass and performance of the ground support are being continually monitored throughout the construction phase.

Jun 13, 2023

By Richard P. Cislo

The evaluation of the effectiveness of the time domain Coal Interface Detector developed by the General Electric Company under contract H0155120 is the subject of this report. The sensor utilizes differences in the time characteristics of shearer vibrations as sensed by an accelerometer mounted on the ranging arm to discriminate the cutting of coal and rock. Pour identical time domain sensors were supplied by the Bureau for field evaluation. The performance of the time domain sensor was evaluated by an extensive field test and data collection program that included four longwall mines and a total of nine mine visits. The intent was to determine the sensor's applicability to a wide range of mining conditions and to document its limitations. Results of the extensive field tests indicate that shearer vibration data processed by GE's time domain signal processing algorithm cannot be used to reliably detect when the cutting drum crossed the coal/rock interface.

Jan 1, 1987

By R. J. Pine

Procedures are described for the application of risk analysis or probabilistic methods to mining geomechanics. The methods are widely applicable to existing mine design models. Detailed examples are given of plane slope failure and of pillar design based on displacement-discontinuity stress modelling and empirical strength assessment. The modelling techniques assessed are the Latin hypercube sampling method, incorporated in a spreadsheet environment, and the general point estimate method (GPEM), programmed in TurboBasic. An example GPEM program listing is included. Both methods are very convenient to use. Probabilistic acceptance criteria for slope stability after Priest and Brown are examined and alternatives are proposed where output distributions of factor of safety are approximately normal or lognormal and output distributions of safety margin are normal. The reliability index is included as a useful measure of variability with proposed acceptance criteria.

Jan 12, 1992

By M Tsai

Tube bundle gas monitoring systems have been used in the mining industry for over 50 years. The initial design was based on four individual gas analysers along with a series of solenoid valves, gas sample conditioning and flow control mechanisms to ensure the correct gas flow stream volume to the analyser. Simtars staff have identified flow control issues when providing operational support to coalmines on numerous occasions. The accuracy of the oxygen analysis is dependent on control of the gas flow to the analyser. Oxygen is one of the parameters used in calculating Graham’s ratio which is used for the detection of spontaneous combustion activity in coalmines. This paper will provide data which identifies the flow control issues by comparing mine site records for the two surface sample lines in the analyser room and the gas cage. Mine sites will be deidentified within the paper. The paper will discuss some of the changes that have been made in modern tube bundle systems and compare the change to the initial design specification developed by the UK National Coal Board, investigate possible operational impacts and provide a technical fix to solve the current flow issues being experienced at some mines.

Oct 12, 2022

By Werner Wenzel

Methods to increase the gas penetration through sinter layers. In the field of agglomeration, sintering has gained importance, specially in Europe; in Best-Europe this trend will continue till the year 1980, since it is quite probable that in the blast furnace burdens with 50-60 sinter, 10-20 % pellets and 20-25 % ore lumps will be employed. In order to meet this demand for sinter, new sinter bands with reaction areas between 300-400 m2 will be constructed. Chemical and physical phenomena during the Suction-Draught-sinter process. Iron ore sintering is generally considered as a burning process where the material contains 90-95 % ash i.e. non-combustible ingredients. Sintering represents a heterogeneous exothermic reaction in which the chemical phenomena as combustion, calcination, hydration, reduction and oxydation are superposed by physical phenomena. The physical phenomena are devided into material transport and simultaniously occurring heat transport processes. The velocity of these combined physico-chemical reactions i.e. the change in the reaction site per unit time determine the efficiency of the sinter process. The gas permeability as an important criterion of heat transport during the Suction-Draught sinter process.

Jan 1, 1971

By John Newby, Mahmood Khwaja, Bernard Theron, Janice McGovern, Bernard Catalano, Michael S. Schultz

Launching a full-size pressurized-face Tunnel Boring Machine (TBM) in difficult ground conditions is always challenging. Recently, few projects have innovated the process by scaling the trenchless method of pipe jacking, and modified steel bell approach, to facilitate the launching of a full-size TBM without the need for large and deep trenches, starter/tail tunnels, or for incrementally installing supporting gear as the machine advances. This paper presents three such projects; evaluates the post-bid contractor proposed modifications; details the innovative use of pre-cast pipe segments to facilitate machine launch; and, provides an overall assessment of the benefits, challenges and lessons learned related to the modified approach.

Jun 13, 2021

By Renato G. Bautista

The solvent extraction separation of nickel, cobalt and their associated metals have been considered for industrial application since the early 1960's. This review of the solvent extraction processes is limited to the industrial applications, pilot plant and the more extensive bench scale studies reported in the literature. The processes with their significant chemical and technological contributions are discussed in detail whenever the information are available. The application of solvent extraction to the nickel-cobalt processing has so far been limited to the secondary separation of nickel-cobalt containing feedstocks derived from other primary nickel-cobalt separation methods.

Jan 1, 1993

By E. Chiyangwa, L. Schoeman

The commercially successful electrowinning and refining of metals typically requires the optimization of the electrolyte composition and operating parameters to produce high quality compact electroplated metal. The prediction of the effect of the electrolyte composition on the structure and morphology of the plated metal remains a challenge. Initial work on the use of polarization measurements to predict and control plating behaviour in electrowinning plants involved potentiodynamic polarization but proved unsatisfactory as accurate and repeatable predictions could not be achieved. The aim of the present work was to develop a reliable galvanodynamic technique specifically applicable to the plating of zinc from sulfate electrolytes with which plant operation may be controlled and optimized. Initial results indicated that plating and nucleation potentials could be measured accurately and repeatably and that the relationship between the two could be used as a predictive tool for the effect of electrolyte composition on the quality of zinc electrodeposits.

Jan 1, 2014

By James H. Russell

The Bureau of Mines used a statistical approach to evaluate the effects of temperature, current density, and composition of the electrolyte on the purity of boron prepared by electrolysis of a fused mixture of boric oxide in potassium fluoborate. The quadratic equation which best fits the data was calculated for a temperature of 650° to 850° C, a cathode current density of 40 to 1,150 amp/ft2,and a boric oxide content of 0.3 to 7.1 molal. The best products, better than 95 percent boron, were obtained when the current density was less than 2 amp/ft2 and the boric oxide content was less than 2 molal.

Jan 1, 1967

By Ihsan Berk Tulu, Ted Klemetti, Deniz Tuncay

Accurately estimating load distributions and ground responses around underground openings plays a significant role in the safety of the operations in underground mines. Adequately designing pillars and other support measures relies highly on the accurate assessment of the mining-induced loads, as well as the load-bearing capacities of the supports. There are various methods that can be used to approximate mining-induced loads in stratified rock masses, both empirical and numerical. In this study, the numerical modeling approach recently developed at West Virginia University, which is based on the modeling approach developed by the National Institute for Occupational Safety and Health (NIOSH), is investigated using the finite difference software FLAC3D. The model includes the longwall panels, the adjacent chain pillar systems, and the different stratigraphic layers of the overburden. Using the 3D model, changes in loading conditions and deformations on the areas of interest, induced by an approaching longwall face, can be examined. This paper details the 3D modeling of a longwall panel utilizing this approach, and the verification of the results against field observations. The studied panel was 360 m wide with a 3-entry chain pillar system and about a 160-m average overburden depth around the studied area. The overburden strata consist of alternating layers of shale, sandstone, and limestone. The FLAC3D results were compared against field measurements from the mine site. The stress change values measured in the chain pillars were comparable with the modeling results. The model also replicated the surface subsidence profile obtained from field measurements fairly well. Overall, the 3D modeling approach was found to be successful for the case study longwall panel.

Sep 23, 2020

By Jacob Masliyah, Zhiang Zhou, Dharamdat Christendat, Tshitende Kasongo, Kevin Hyland, Zhenghe Xu, Ted Kizior, Douglas Cox

"A novel on-line visualization system, previously developed at Syncrude Canada Ltd., has been modified to characterize rising bubbles, particles and particle-bubble aggregates in a flotation process. With this system, the bubble size and rise velocity in a laboratory flotation cell can be determined. The technique allows the loading of solids on bubbles to be visualized, thereby providing an in-depth understanding of sub-processes of flotation. A step-by-step data processing procedure is presented. The applicability of the developed system to mineral flotation and bitumen extraction is discussed. Under batch flotation conditions in a laboratory Denver cell, three main bubble-particle attachment patterns are observed. They are: i) single particles attached to single bubbles, ii) particle aggregates loaded on single bubbles; and iii) a group of particles aggregated with a group of bubbles. The results demonstrate that the on-line visualization system is a powerful tool for understanding and diagnosing flotation processes.INTRODUCTIONAir (Gas) bubbles are an indispensable component in a flotation system. Both industrial practice and theoretical analysis indicate (Yoon, 1993; Diaz-penafiel and Dobby, 1994) that the size and population of bubbles are two important process parameters in modeling flotation. More recent investigations (Finch, et al., 1999; Gorain, et al., 1997) suggest that for a given flotation system, bubble surface area flux, defined as the air liquid interfacial area per unit time and unit cross-sectional area of flotation cell, showed a better correlation with the flotation rate constant. As a result, the bubble surface area flux is now being considered as a key parameter to account for the combined effect of bubble size and population in evaluating the performance of flotation machines and modeling flotation processes. However, the success of using bubble surface area flux in flotation process modeling largely depends on how accurate it can be determined or estimated (Finch, et al., 1999)."

Jan 1, 2000

By Harry Jomini

Introduction The Wakefield plant of the Aluminum Company of Canada, Limited - a member of the Aluminum, Limited, group of companies - produces magnesia, magnesia fertilizer ingredient, and hydrated lime, from brucitic limestone. Wakefield is on the Gatineau river in Wakefield township, Quebec, some 22 miles north of Ottawa. The plant is near the western bank of the river adjacent to the Ottawa-Maniwaki highway and branch line of the Canadian Pacific railway. The plant is unique in the sense that it is the only place in Canada where brucite is processed. It is also distinguished for its outstanding safety record, as not a single lost-time accident occurred during either 1948 or 1949. The plant is amply provided with safety and comfort provisions in keeping with the standard practice in all of the twelve plants operated in Canada by Alcan and its associated companies. History Following the identification of brucite in the Rutherglen and Bryson districts in Ontario, occurrences of the mineral were discovered in the Wakefield area, Quebec, in 1939. After exploratory work on these deposits and investigation by the Bureau of Mines, Ottawa, on a method of extracting the brucite from the ore, a plant for treating the ore from the Maxwell property was built in 1941 by the Aluminum Company of Canada and commenced operations in early 1942. The process used is more or less in accordance with the method worked out by Mr. M. F. Goudge of the Bureau of Mines.

Jan 1, 1950

By Ilija Ilic

Recovery of tin from tinplate and production of good-quality detinned-plate for further processing in ironworks has been the subject of interest for many years. Tinplates are mostly used for production of tin containers for food industry and consumer goods. The research carried out so far included determination of the parameters of dissolution of tin from tinplates by alkaline solution of NaOH and electrochemical recovery of tin from the alkaline solutions. During leaching, NaNO3 and methanitrobenzoic acid (MNBA) as oxidants were studied. By leaching the waste tinplate which contains 0.31 % of tin with a solution of 1.12 mol/dm3 NaOH, 0.26 mol/dm3 Na2CO3 and 0.09 mol/dm3 MNBA at temperature of 70°C for 60 mm, a degree of tin leaching of 97 % was attained. MNBA facilitates oxidation of Sn2+ into Sn4+ suitable for obtaining compact, and not spongy, Sn cathode deposit, as it was the ease earlier. Recovery of tin by electrolysis from solutions obtained by leaching was studied to determine the effect of electrolyte composition on the quality of cathode deposit and the degree of electric current efficiency. Experimental results obtained at a laboratory level were checked on an enlarged laboratory set up where continuos leaching of tin from waste tinplate and its electrolytic recovery from the solution obtained were carried out. The experimental set-up -operated under semi-industrial conditions, and about 500 kg of waste tinplate was processed yielding about 1.160 kg of tin (99 % Sn).

Jan 1, 2000

By A. A. Brant

Self-potential methods are based ?on measurements on the surface of voltage distributions caused by natural sub-surface oxidation phenomena. The attempt is made to. correlate voltage minima or maxima with the location of mineral materials or geological conditions which may give rise to such naturally produced spontaneous potentials. Any orebody undergoing oxidation is a source of electric current. Ground waters carrying free oxygen attack the upper surface of the body, rendering this the positive pole of a galvanic cell, with the lower portion of the body the negative pole and the surrounding weak acidic waters the electrolyte. Current flow is from positive to negative through the orebody and negative to positive through the electrolyte, i.e., through the surrounding rock. The upper end of a steeply dipping, tabular orebody is hence indicated as lying below the point on the surface where the largest negative potential is observed(l). From its basis, it is apparent that the self-potential method was developed primarily for ore exploration.

Jan 1, 1942

Societal expectations about how the industry operates and treats its people will be a key driver in the development of the Australian mining industry over the next 20 - 30 years (Moffat, Mason and Littleboy, 2009). Understanding these expectations will be critical in maintaining what much of the minerals industry calls its 'social licence to operate', or its public acceptance or approval. Yet what constitutes this social licence is poorly articulated, with little published research exploring the concept at a local operational level or at the national level in Australia or internationally. This research aimed to explore the societal expectations of the mining industry in Australia and test a participatory methodology to articulate them. Three workshops were conducted with a sample of 24 members of the 'Australian voting public' to explore community objectives for the onshore exploration and mining industry, and the underlying expectations for how the industry should operate in the future. Qualitative analysis of this data revealed three overarching objectives for the onshore mining industry held by participants. They thought that the industry should: advance Australia's national interests (including social well-being); minimise environmental impact, and; act in a socially responsible manner. Within each of these three key themes, or objectives, a number of tensions were evident in the views of participants regarding the trade-offs they are willing to make to secure economic benefit from mining, as well as the basic conditions for socially acceptable mining. These data provide an insight into the conditions for a national social licence in Australia for the mining industry, and the means for its realisation.

Jun 1, 2010

By Edward L. McHugh

The appraisal of mineral resources of the Challis National Forest, Idaho, by the U.S. Bureau of Mines, was made so that the mineral resources of the forest could be appropriately considered in land use planning. Information from this study is intended to help the U.S. Forest Service to incorporate mineral resource data into forest plans. The study was done in conjunction with the U.S. Geological Survey, which released a companion report on the geology and mineral potential of the Challis National Forest in 1989. Mineral development activity in and under the Challis National Forest has been of great economic significance to Idaho and the United States. Since the 1960's, mines within the forest have produced mineral commodities worth more than $590 million A current (1989) commodity prices. Identified mineral resources have a gross value of about $2 billion at current prices, including 8 strategic or critical minerals. The U.S. Bureau of Mines study identified and described 723 active and inactive mineral properties within the forest. Mineral properties with identified resources were evaluated to determine their economic significance, and an assessment was made of the feasibility of mineral development. Of the 2,516,191 acres in the Challis National Forest, about 390,000 acres were classified as having mining development interest commercially important mineral production, mainly of molybdenum, gold, and silver from the Challis National Forest is likely for the foreseeable future.

Jan 1, 1991

By Yael Miron

Two recent unplanned detonations occurred during blasting operations in sulfide-bearing ores in a Nevada gold mine. Other premature detonations have also reportedly occurred at other Nevada, California, and Arizona operations within the past few years, with increasing frequency. Unplanned or premature detonations can be extremely hazardous to life and can cause extensive property damage. A miner was injured in one of these occurrences. This report, by the U.S. Bureau of Mines, is intended to acquaint personnel involved in such mining activities with the basic causes for these accidents. These causes include the exothermic oxidation of pyrite (FeS2) and formation of ferrous sulfate (FeS04), the exothermic and energetic reaction of the ferrous sulfate with ammonium nitrate-fuel oil (ANFO)-based explosives, and the associated elevated temperatures that can set off detonators and explosives in the boreholes. Recommendations for safe operation by the Mine Safety and Health Administration, the Bureau, and the mine involved with the recent incidents include monitoring temperatures in the blast holes, analyzing for sulfate and ferrous ions, and limiting the time between loading and firing in accordance with conditions in the blast holes. Other procedures for safe operations should fit specific conditions in, the mines.

Jan 1, 1992

By Boris J. Kochanowsky, Burke O. Trafton

Because of the strict requirements on the quality of limestone that are dictated by the users, the operator was compelled to find new approaches to produce a product of uniform and acceptable quality. The raw material is controlled and monitored every two minutes by a special computer in order to ensure its quality. The required minimum and maximum quality constraint had an adverse effect on performance and consequently cost. In order to improve this performance, a Monte Carlo simulation model was developed and tested for the optimal truck allocation. The input data is based upon the distribution of equipment performances and costs.

Jan 1, 1969

By H. T. Mulryan

Talc is used as an essential ingredient in a wide variety of plastics applications ranging from polyester body patch compounds through polypropylene automotive, appliance, and household furniture components to high performance parts made from liquid crystal engineering resins. The paper focuses on polyolefin applications; the three tier market for talc in polypropylene; the effects of various talcs in typical compounds; and trends in each market segment. Emphasis is given to emerging markets, examples of which are polypropylene compounds which mimic higher cost resins, and polyethylene films, customer requirements for talcs for these purposes are discussed.

Jan 1, 1993