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By Sofia Martins, Anna Lichtschlag, Sven Petersen, Fernando Barriga, Bramley Murton, Adeline Dutrieux

"Sediments in the vicinity of the hydrothermal seafloor massive sulphide (SMS) mounds are characterized by high concentration of metallic particles. They result from a long process of weathering of the primary mineral deposits and have been accumulated in depressions by mass wasting and hydrothermal plume fall-out. We present here the first results obtained on pore waters analyses of such sediments in distinct geological seafloor environments (in low-temperature hydrothermally active zones, on extinct hydrothermal mounds and in a remote depositional channel). Vertical concentration profiles suggest that the pore fluid composition is affected more by seawater circulation compared with hydrothermal fluid flow in all environments. The composition of pore fluids is affected by diagenesis and redox processes in the distal depositional channel where Mn2+ is released at depth with Cu2+.IntroductionMarine hydrothermal fields, hosting seafloor massive sulphides, are potential resources for future deep-sea mining and might become economic reserves for the industries. They are widespread at mid-oceanic ridges, arcs and back-arc spreading centers (Hannington et al., 2011; German et al., 2016). Sediments in the vicinity of these fields can contain unusually high concentration of Fe, Mn, Zn and Cu among other metal elements (Shearme et al., 1983). These hydrothermal, or metalliferous, sediments result from a combination of processes such as collapsing and weathering of chimney material, filling of the channels by turbidite-like mass wasting, in situ authigenic mineralization and hydrothermal plume fall-out (Goulding et al., 1998; German et al., 1990). The sediments contain important indicators reflecting the development of the hydrothermal systems. Because of their widespread distribution and metal content, they themselves can be considered potential mineral resources. Circulation of seawater through these deposits, however, often modifies the sediment composition by oxidizing the sulphides into oxyhydroxides and clays causing mobilization of the metals. To address the importance of alteration and diagenesis of these hydrothermal sediments, including the result of seawater circulation, we investigated the post-depositional processes occurring in the hydrothermal sediments at the TAG Hydrothermal Field (Mid-Atlantic Ridge, 26°N), focusing on the mobility of metallic cations in a number of different seafloor environments."

Jan 1, 2017

By P. H. Morris

Nineteen field trials of the co-disposal of fine coal tailings and coarse coal wastes were conducted at the dual Goonyella-Riverside mine in Queensland and at the Hunter Valley No. 1 and Warkworth mines in New South Wales, Australia. The profiles of and the sorting that occurred on the co-disposal deltas are described and an existing theory of subaerial deposition, originally developed for mine tailings alone, is shown to apply to the co-disposed wastes. This enables the dimensionless profiles of large deltas, which may take years to deposit, to be predicted from data obtained from a small delta formed in a few days or even hours

Jun 19, 1905

By F. H. Deist, M. P. Roberts

"The Collieries Research Laboratory of the Chamber of Mines of South Africa is developing a coherent system of programs to aid in the full spectrum of activities arising in the planning of new as well as operating mining enterprises. It is the purpose of this paper to describe the design and application of two subsystems in the complex.One of these subsystems is an initial version of a production simulator. This program draws upon a model of a mining enterprise and simulates the operational and financial aspects of a set of alternative mine production plans.These plans are specified in terms of proposed sequences of operations. Details such as reserves, production rates, resource requirements and so on, are taken from the model.Physically, the model takes the form of a cross-referenced data base, maintained by means of a general file maintenance system which is another subsystem described.The paper concludes with a description and analysis of the first practical application of the two programs."

Jan 1, 2014

By Doerner H. A.

From thermodynamic calculations Maier predicted that zinc oxide and methane would react at specified temperatures substantially according to equation (1). (1.) ZnO + CH4 = Zn (gas) + CO + 2H2. Other reactions that may take place are (2.) CH4 = C + 2H2. (3.) ZnO + CO = Zn (gas) + CO2. (4.) ZnO + H2 = Zn (gas) + H2O. Maier predicted that 870°C would be the critical temperature above which reaction (1) would take precedence over reaction (2) and that reaction (1), at equilibrium, would be substantially complete at or above 927°C. Theoretical considerations indicate that reaction (1) is reversible: this is supported, but not proved, by experimental data. The other reactions are known to be reversible. At low temperatures reaction (2) requires a catalyst and it is slow below 1000°C. Reactions (3) and (4) are rapid, but the equilibrium constants are such that only small concentrations of CO2 or H2O can be produced below 1000°C. Maier calculated that CO2 should not exceed 0.5 per cent at 870°C., and the calculation for water vapor gives a still smaller order of magnitude.

Jan 1, 1931

By Nilabjendu Ghosh, Satyendra Kumar Singh, Gautam Banerjee, Harshit Agrawal

High-production methods like longwall mining with hydraulic powered supports are necessary to increase underground coal production in India. Longwall mining had a mixed success record for Indian geo-mining conditions. In this paper, an analysis is presented to optimally design an array of chain pillars in multi-seam longwall mining panels in the deepest coal mine in India. The study found that a chain pillar of 80-m width and 195-m length is necessary for long-term stability without any reinforcement. It was also observed that an optimum chain pillar can be designed by providing suitable side reinforcement (side bolting) which will reduce the chain pillar dimensions to 55-m width and 160-m length. Optimum design of chain pillars will reduce the coal locked up in these chain pillars by ~ 77%. This will also reduce the gestation period of longwall mining panel development. This paper also evaluates the maximum tensile subsidence strain induced at the surface and finds that the values are within the safe working limit of 3 mm/m. Thus, this paper finds direct application in the design of future multi-seam retreating longwall mining panels in Indian geo-mining conditions.

That electricity is an important and valuable agent, the limit of whose capacity for utilisation is as yet unknown, is a truism; although enormous advances have been made, the possible developments are yet greater. Mining, along with other industries, shares already to a large extent in the practical utilisation of this agent. Electrical engineers have been employed for several years past in developing and applying electricity to all classes of machinery, and for every purpose where power is required and in no instance, that the writer is aware of, has its use been curtailed in favour of any other agency now known, while extensions are continually made. The first modern electric motor was shown at the Vienna Exhibition of 1873, and it was used to work a pump through a mile length of cable but it was not before 1878, that an electric motor was put into daily commercial use by Messrs. Chretian and Felix to work a beet sugar hoist. This early plant effected a saving of 40 % as compared with hand work.In 1879, the first Electric Railway was constructed for the Berlin Exhibition, and in the same year, Mr. T. A. Edison was running an experimental line at Menlo Park. The first electric line opened for the public, was constructed by Siemens and Halske, in 1881, at Lichtenfelde, and was 11 miles in length.

By Walter J. Huff

"INTRODUCTION The technical studies conducted by the Explosives Division of the Bureau of Mines have been summarized in a series of publications issued annually for the past 10 years. 3/ The following account covers studies undertaken from July 1, 1944 to June 30, 1945. The work is set forth under a number of main headings to correspond to the organizational structure of the division, the various activities being under the immediate direction of unit chiefs, who report to the author. Specific credit it due to the unit leader and his assistants.Determination of Ignition TemperaturesThe ignition temperature of mixtures of isobutane and air were determined by the static method using a 131-cc. quartz bull. 5/ The results obtained follow: Prevention of Benzene-Air Explosions by Addition of Nitrogen and Carbon Dioxide The elimination or mitigation of the explosion hazards of combustible gases is a part of the work undertaken by the Bureau of Mines in promoting safety. Explosions can be prevented by the maintenance of concentrations that lie outside the inflammable limits. A procedure has been developed whereby the inflammable limits of many complex gaseous mixtures may be calculated in a rather simple manner without requiring toilsome laboratory experiments. This procedure has been outlined in a number of previous publications. 6./ During the fiscal year under review, essential data required for the calculations of complex combustible gas mixtures containing varying percentages of benzene were obtained. Benzene vapor is a normal constituent of many manufactured gases and is widely used in the solvent industry and in the manufacture of high explosives."

Oct 1, 1946

By C. F. Lucks, W. D. Wood, H. W. Deem

Electrical ad thermal-conductivity measurements have been made on titanium and 6 titanium alloys. The following expression was derived for calculating thermal conductivity from electrical conductivity: K = 0.626 s T x 10-8 + 0.00497 where K = thermal conductivity, cal sec-1 cm-2 cm0C-1 s = electrical conductivity, ohm-]cm-1 T = temperature, deg Kelvin This expression gives calculated thermal conductivities that are not in error by more than 10 pct from the experimental values for A-55 titanium and the 6 alloys measured; namely, A-110AT, C-110M, C-130AM, Ti-6A1-4V, Ti-140A, and Ti-155A, which are representative of the presently available commercial a and a-ß titanium alloys. THERMAL conduction in a gas, liquid, or amorphous solid is accomplished by energy diffusion from molecule to molecule, a relatively slow process. For this reason, such materials have a low thermal conductivity. When a material is crystalline, there is in addition a heat transfer by a vibratory motion of the crystal lattice. It is the contribution of this lattice conduction that makes a crystal a much better conductor than a gas, liquid, or amorphous solid. Lattice conduction, however, does not account for the relatively enormous thermal conductivity of a metal. This is explained by the freedom of movement of valence electrons. These valence electrons drift in a metal in a direction toward a drop in electrical potential and, to a lesser degree, in the direction of a temperature drop in the metal. Since both the electrical and thermal conductivities of a metal depend upon the presence of free electrons, there should be some relatively simple relation between the two. Wiedemann and Franz in 1653 first discovered an approximate empirical relation between the electrical and thermal conductivities of metals at the same temperature. This ratio varies appreciably with temperature, and Lorenz later showed that by adding a temperature factor to the Wiedemann-Franz ratio the value of K/(s T) is constant, where K is the thermal conductivity, a the electrical conductivity, and T the absolute temperature. This Lorenz constant shows a greater variation for alloys than it does for pure metals, the ratio increasing slightly as the proportion of alloying elements increases. It has been found that a closer correlation between electrical conductivity and thermal conductivity can be obtained by means of an equation of the form K - A s T + B [1] where A and B are constants. In this equation the term AsT is the contribution of electronic conduction and B is the contribution of lattice conduction to the total thermal conductivity. EXPERIMENTAL MEASUREMENTS Electrical-resistivity and thermal-conductivity measurements on titanium and 6 titanium alloys serve as the basis for determining an equation of the K = AsT + B type for titanium alloys. Specimens—Table I shows nominal compositions of the 7 metals on which electrical and thermal conductivities were measured. The electrical and thermal-conductivity specimens for each alloy were taken from stock of the same heat and usually from adjacent sections of the same bar. All of the metals measured were in a mill-annealed condition. Methods—Electrical-resistivity measurements

Jan 1, 1959

By Thomas C. Anderson

Tiedback walls are now recognized and accepted as a good solution for a variety of structural problems: ? Retaining Walls and Bridge Abutments in cut situations ? Landslide stabilization ? Repair/support of existing walls Acceptable techniques have been developed for anchoring in cohesive and granular soils and in any kind of rock. Methods have been developed for adequately protecting tieback tendons against corrosion and for testing every tieback to verify its long-term load-carrying capacity. However, the major problem that the industry faces today is how do we get constructable and economical tiedback walls contracted for and built with minimal claims. This paper will explore the issue of "constructability" through a look at specific problems from actual projects. From a research report from the Construction Industry Institute, Austin, Texas (1986), constructability is defined "as the optimum use of construction knowledge and experience in planning, design, procurement and field/operations to achieve overall project objectives." Maximum benefits occur when people with construction knowledge and experience become involved at the very beginning of the project." The design and installation of tiebacks has been developed primarily by specialty contractors; each contractor has evolved its own methods of performing the work, and consequently, many of the techniques are patented and proprietary. The real question is, how do we make effective use of this knowledge and experience during the design phase of the project?

Jan 1, 1991

By L. Lui, A. Cauchon, A. R. Laplante

"The gravity circuit at Les Mines Camchib Inc. consists of two pinched sluices to bleed a feed to one of two 76 cm (30"") Knelson concentrator. The Knelson concentrate is upgraded to smeltable grade with a smaller Knelson (18/30 cm) and a riffleless table. Their tails are column cyanided and washed prior to recycle to the grinding circuit. This paper details size-by-size circuit performance. The Knelsons recover around 90% of free gold (as determined by Mozley Laboratory Separator), even below 37 µm. The sluices are ineffective, with upgrading ratios around 2, but approaching unity in the fine sizes. Much of the effectiveness of the circuit lies in the high gold circulating loads in the grinding circuit, which partly atone for the poor sluice performance, and the ability of the Knelsons to recover free gold. Secondary upgrading recovers slightly above 99% of the primary concentrate gold, 90% of it in a 65% Au concentrate and the balance in a heavily loaded (10 to 20 oz/st) pregnant solution. INTRODUCTIONBackgroundThe operating performance of the mill of Les Mines Camchib Inc. has been described earlier (Laplante et al., 1989). The presence of significant chalcopyrite (1 % and up) makes flotation necessary prior to cyanidation, to limit cyanide consumption and minimize environmental impact. In 1982, the presence of very high gold circulating loads in the grinding circuit lead to the commissioning of a gravity circuit, schematically shown in Figure 1. Gravity recovery of gold has been found beneficial because it increases metallurgical recovery by 1-3% (Laplante et al, 1987), as only part of the flotation tail is cyanided, and economic recovery, because of the lower net smelter return of gold in the flotation concentrate (as compared with the gravity concentrate). The latter increase is estimated, with a net smelter return of 95%, at 1.5% when gold recovery by gravity is equal to 30%. In early 1988, a sampling program was initiated to characterize the behaviour of gold in the grinding/gravity circuit. This paper reports on the results of this study."

Jan 1, 1990

By N. Kyriazi

The U.S. Bureau of Mines subjected the CSE SR-lOO self-contained self-rescuer (SCSR) approved by the National Institute for Occupational Safety and Health (NIOSH) and the Mine Safety and Health Administration (MSHA) to a series of laboratory treatments designed to simulate various environmental conditions in underground coal mines. The tests were designed to predict the ability of the self-rescuers to withstand those environmental stresses without causing a decrease in wearer protection. The apparatus were heated to 710 C for 48 h, cooled to -450 C for 16 h, vibrated for 9 h, and dropped 1 m on each axis. A critical concern was internal damage to an apparatus, without any obvious external signs, that would cause it to malfunction or seriously degrade its performance. Carbon dioxide (C02) levels in apparatus with combined treatments were higher than in apparatus with individual treatments and untreated apparatus. The higher levels remained within safe limits, however. None of the treatments caused venting of the small oxygen cylinder that provides starter oxygen. Some bottles were found to be empty because of manufacturing defects in the burst disks. This problem was corrected in later models. The heat treatments did make the case ends more difficult to remove and the breathing bag sticky and subsequently more difficult to unfold. An apparatus that was dropped and vibrated had a broken desiccant bag that released some of its contents which compromised the seal of the relief valve. The case was dented from the drops. As with the first-generation self-rescuers, if there is visible damage to the case of the apparatus, the apparatus should be considered to be internally damaged and must be removed from service.

Jan 1, 1990

By W. L. Garrison

Improvements continue to be made in rapid excavation and tunneling technology. There are several ways to examine the impacts of such improvements. The most common procedure is to monitor current developments and to evaluate prospects for expansion of present types of uses. Other approaches are called for, however, if the technology might be used in ways not now imagined, if the search is for information for managers of technology development, and if the issue is that of the wise use of the technology by society. The first section of the paper will pose these matters as questions. These questions will be examined from the point of view of the processes of technology development and utilization, and then further examined against the backdrop of processes at work within the urban area. Such an examination will provide insight into the way technology developments should proceed. The final section will present some comments that may be useful to those guiding the development of the technology and to those who might provide leadership for its wise utilization. THE QUESTIONS Three questions are posed: 1. Are there uses for the technology beyond further penetrations of its present markets? 2. Can information be supplied to managers of technology development so that they may improve the assignment of priorities among development choices? 3. How can society make wiser use of the technology?

Jan 1, 1974

By K. Whysner

The recycling of metal resources in mining influenced water (MIW) requires a paradigm shift from within the mine water treatment industry. The potential to recover zinc for beneficial use in the micronutrient fertilizer industry was investigated through a survey of zinc micronutrient fertilizer representatives. An application of the findings to a case study of the Argo Tunnel influent MIW was then implemented. It was concluded that the potential to beneficially reuse MIW residuals in fertilizers exists; the current process sequences of treatment will need to be modified if metal recycling is to be prioritized.

Feb 27, 2013

By William D. Hissem

While much technology has been developed and brought to bear in the area of blasting applications, the foundation work required for success in the muck pile begins with the drilling program.

Jan 1, 1997

By J. B. Rasmussen

As part of a purchase of a fleet of Caterpillar 785 trucks, Round Mountain Gold Corp., Cashman Equipment Co. and Caterpillar Inc. entered into a four-year contract for the major maintenance of the fleet of trucks. This contract includes fixed costs and guaranteed availability. The results have been excellent, and the fleet of trucks performs well. History The Smoky Valley Common Operation is a unique mine. Through a mixture of diligence and foresight, it has become the largest open-pit, heap leaching gold mine in the world. This was no small feat considering the remote area surrounding the mine. Round Mountain is located in north-central Nye County, NV. To the east of the town and mine lies the Central Toquima mountain range. To the west is the Toiyabe mountain range. Between them is the Big Smoky Valley, a flat expanse of sagebrush, salt grass and fine dirt.

Jan 1, 1991

This paper provides a review of the chemical reactions occurring in the submerged arc processing of chromite ores. The excavations of industrial furnaces have shown that the charge, as it descends through the furnace, passes through a number of distinct reaction zones. Each zone is characterised by differing process conditions and reaction products. The phase equilibria, reaction steps and mechanisms occurring as the charge progresses through the furnace are examined, and the potential influences of these factors on the process outcomes are discussed.

Jan 1, 2004

By J. VAN DEN BERC

Tin production and export from the Far East are still a long way off from the prewar figures. The Malayan Peninsula, which had a rather good start directly after the war largely because of stock piles found in Singapore and elsewhere, has since been hampered in the rehabilitation of its tin mines and dredging operations by material shortages and, more recently and more severely, by revolts and attacks of communist elements and gangster bands. These hindrances make working in the mines dangerous and form a daily threat against the valuable and highly vulnerable dredges. Contrary to the conditions in Malaya are those on the tin islands of Billiton, Banka, and Singkep-all in the Netherlands East Indies-where the Dutch have re-established peaceful relations with the population. Dutch efforts since the fall of 1945 have been rewarded by continuously increasing production, extension of production facilities, and return of moderate prosperity, complete safety, and all-out co-operation among the population ? native and Chinese ? to the benefit of all concerned.

Jan 1, 1949

By R. D. Stewart

Paper presented at the conference: Risk assessment in the extractive industries, held in Exeter, UK, 23-24 March 1994, and first published London: IMM, 1994, preprint volume, 18pp., 5 refs. A seismic risk assessment method has been developed for application to rockburst prone deep-level mining sites which have sufficient seismic coverage. The technique utilises several seismic hazard parameters simultaneously and assesses the seismic risk on a daily basis according to the individual levels of these parameters. Critical levels are determined from investigation of the long-term behaviour of the parameters in relation to recorded potentially damaging seismic events. The method has been applied to a data set comprising 15 months' worth of seismic data, with encouraging results

Aug 1, 1995

By R. M. Sweetin

Detailed descriptions by operating area of the Kidd copper smelter are presented, together with accounts of complement staffing, training, and preparation activities for smelter start-up in June 1981. Concentrate tonnages smelted in the first twelve months of operation were constrained by the capacity of the furnace off-gas system. However, modifications designed and introduced over that period, plus sustained efforts by operations and maintenance personnel have resulted in stepwise improvements in smelter performance.. Consistent operation at design feed rates has been well demonstrated over the third and fourth smelter campaigns and efforts continue on further improving the continuous smelter on-line times and increasing campaign life. In November 1982., following a seventeen month preproduction period, the Kidd smelter attained full operating status.

Jan 1, 1983

By Haldane J. S.

(Paper presented at the Institution of Mining Engineers' general meeting held in London on 8th June 1916.) It was shown in the last Supplement to the Registrar-General's Reports, in connection with the census of 1901, that the general death-rate among colliers was considerably lower than in the great majority of occupations but that there is an exception to this in the case of colliers above the age of 55. Examination of the statistics finds that the excessive death-rate among old colliers is to a large extent only apparent, and that the real excess of bronchitis from which they have suffered has greatly diminished. It is concluded: (1) that good ventilation is of considerable importance to the health and continued working efficiency of miners, as well as to their safety from accidents; and (2) that there is no real statistical evidence of harm resulting from the inhalation of coal-dust or shale-dust in the quantities ordinarily breathed by miners, and a strong presumption that the dust they breathe protects them against serious dangers from bacilli that are removed from the lungs by the dust-clearing cell mechanisms

Dec 1, 1916