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Discussion of the paper Of JAMES JOHNSTON, presented at the New York meeting, February, 1914, and printed in Bulletin No. 85, January, 1914, pp. 107 to 133. CHAIRMAN E. GIBBON SPILSBURY.-I would like to call attention to the fact shown in this paper that less than five years or perhaps seven years ago nobody had thought it possible to cyanide with success silver ores. The cyaniding of silver and gold ores was first of all started in Mexico, and gradually extended to this country in the case of the silver ores alone. The average extraction, I think, for the metals in Mexico, in the case of the silver ore, is less than 85 per cent., whereas here, in the case of a very complex ore, carrying a high percentage of sulphur and arsenic, and other objectionable elements, the ore has been treated so as to extract an average of 95 per cent. of the silver contents of the ore. It is really a phenomenal revolution in the metallurgy of silver ores which has been demonstrated and worked out at the Nipissing mines. GEORGE A. PACKARD, Boston, Mass.-I would like to suggest a slight modification, perhaps, of the statement which is made that no one considered cyaniding of silver ores up to five, or perhaps seven years ago, because in 1897, when I was at Mercur, Utah, one mill near there was operating on silver ores. It did not operate very successfully from a commercial standpoint, because they did not have a great deal of ore, but the extraction, I was told, was very satisfactory, and I am quite confident that it was, because, as suggested by the name, Chloride Point, the ores were silver chloride ores, and of course very easily soluble. Some years before that, in 1892, I made some tests myself. I spent three months making tests on more or less complex silver sulphide ores at Virginia City, Mont., and while our tests on the plain sulphide ores, finely ground, were quite successful, on account of the presence of a small amount of copper we did not work out a satisfactory solution of the problem at that time; although since then a cyanide plant has been erected and for at least eight years these ores have been treated by cyaniding at Virginia City, and the mill is still in operation. The period of five to seven years should, therefore, be modified considerably, in justice to the pioneers in the cyanide processes. REGINALD E. HORE, Toronto, Ont., Canada.-I hoped that there would be metallurgists from Cobalt here to present and discuss Mr. Johnston's paper. In their absence a few remarks from me may help to make clearer to you what they have accomplished.

Jan 6, 1914

By Jaime Lomelin

The brines from the sub-surface of the Laguna del Rey dry lake are pumped to Química del Rey, S. A. plant, where they are cooled in adiabatic crystallizers precipitating sodium sulphate decahydrate. This salt is dehydrated in multiple effect evaporators and dried in rotary kilns producing high purity anhydrous sodium sulphate. The spent brines from the sodium sulphate operation are concentrated in solar ponds, precipitating astrakanite and leaving a brine with a higher concentration of magnesium ions. This brine is treated with calcium chloride solution to eliminate the remainder of sulphates, leaving a solution of magnesium chloride ready for the manufacture of refractory grade magnesium oxide or periclase. The magnesium chloride is reacted with dolime to produce magnesium hidroxide which is washed, filtered, and calcined to produce soft burned magnesium oxide, which is briquetted and dead burned to produce the periclase.

Jan 1, 1984

By M. C. Fuerstenau, D. N. Collins, R. B. Bhappu, D. N. Moir

D. N. Moir (Senior Scientific Officer, Warren Spring Laboratory, D.S.I.R. Stevenage) and D. N. Collins (Scientific Officer, Warren Spring Laboratory, D.S.I.R., Stevenage, England) — During work on the petroleum sulphonate flotation of beryl in 1959 at Harwell, and subsequently at Warren Spring Laboratory, effects similar to those mentioned by the authors were noticed. Brief details of some of this work were given to the 6th International Mineral Processing Congress at Cannes.' It is interesting to note that the authors experienced strong activation effects with Fe+++ ions on beryl when using petroleum sulphonate collectors. This phenomenon was of interest in our work when

Jan 1, 1963

By E. Gilpin

Any estimate of the economic mineral value of an unvisited district is to the mining engineer largely a comparative one. If he knows that certain minerals characterize any given geological horizon he naturally draws upon his experience of the same ores as met by him cinder similar geological conditions. And if he has not had the personal experience, the investigation of the geology of a similar district as given in a trustworthy report enables him to lay a fair basis for conclusions. In a general way these conclusions are of value, and while they pronounce on the possible mineral fecundity of a given district, they

Jan 1, 1890

By Lawrence Mirabelli, William Hissem, Gary Veltrop

Capital Quarries Company, Inc., Jefferson City MO produces aggregate products for road base, asphalt, concrete and concrete block. With their production quantities small in comparison to those produced by the goliaths of the aggregate industry, they find it necessary to constantly stay on the leading edge of best practices for cost control, process and production improvement to sustain a successful business. In the words of Eric Strope, President, “The safety of our employees is foremost. They all work hard each day. They are focused on keeping our cost to manufacture down. As I see it, we cannot work any harder so we must work smarter!”

Jan 1, 2009

By F. Duan, J. Pfarr, J. M. Goris

"The U.S. Bureau of Mines, in cooperation with the Homestake Mining Co. and the University of Utah, is conducting a field demonstration to evaluate the behaviour of rock masses supported with cable bolts. One of two rock masses being studied is supported with both conventional and birdcage cables. This rock mass is located between the 6500 and 6650 levels of the 45-48N stope, 21 ledge. The second rock mass is the hanging wall of the D-limb stope between the 3500 and 3650 levels near the Ross Shaft and is supported with conventional cables. The primary objectives of the project are to monitor the behaviour of the two rock masses during mining using extensometers and cable support strain gauges, after which the rock will be modelled using the finite-element code UTAH III. Field data will be used to verify the modelling. In addition, a comparison between the effectiveness of conventional and birdcage cables will be made.45-48N StopeThe 45-48N stope is located in the 21 ledge between the 6500 and 6650 levels and contains about 233 000 short tons of mineable ore. The orebody lies within the Homestake Formation and is very irregular being approximately 200 ft long and 75 ft wide. Between the 6500 and 6650 levels, it dips from 35 degrees to 60 degrees east with a near-vertical plunge to the south. Mineralization is characterized by arsenopyrite and pyrrhotite with minor gold. The contact between the Homestake and the overlying Ellison Formation creates a plane of weakness along localized graphitic layers. The footwall dips at approximately 60 degrees but between 100 ft and 120 ft above the 6650 level , the hanging wall flattens to almost 20 degrees causing a significant mining problem."

Jan 1, 1991

By Staton L. Tainter

"The Johnny Bull and Silver Knight claims were selected for exploratory diamond drilling after having been examined by the Bureau of Mines 3./The property was considered attractive for two reasons: (1) A prominent outcrop, recognized as an extension of the Tennessee vein, persisted over a distance of 2,000 feet across the claims; (2) its proximity to the known ore shoots in the Tennessee-Schuylkill mine, one of the largest zinc-load producers in Arizona.Actual drilling was started September 18 and was terminated December 8, 1943. Eight holes, aggregating 2,979.5 feet, were drilled with two machines. ACKNOWLEDGMENTSIn its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resource to the end that they make the greatest possible contribution to national security and economy. I is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R.G. Knickerbocker, chief, analyses samples and performs beneficiation tests."

Jan 1, 1947

By A. J. Metz, Roberto Nevarez

One popular method to stabilize slopes is the use of deep foundation elements to support lateral loads from an unstable soil or rock mass. Drilled deep foundation elements are often selected due to local availability of equipment, access concerns, cost considerations and post-construction aesthetics. Often, one or more rows of deep foundation elements are installed running parallel to the slope. The elements in each row may or may not be connected through a cap beam. They work primarily in bending, and resist slope movement by transferring the earth pressures down below the potential slip surface. Design of these systems considers the effect of arching

Nov 1, 2023

By M. U. Ozbay

This paper presents an overview of the research that has been carried out to improve the understanding of the fracture processes occurring in rock under high levels of stress. The onset and growth of fractures are studied by means of laboratory model testing, and the results obtained are used in the calibration and validation of the numerical model DIGS, which is based on displacement discontinuity. The results obtained so far have shown that, while there are overall similarities between the experimental results and the numerical simulations, improvements to the experimental procedures and the DIGS are required for a detailed mechanistic understanding of shear-band orientations and extension fractures.

Jan 1, 1996

By Ch. Roumpos

The present contribution investigates the way of applying benchmarking for large-scale open-pit mining operations based on sustainability indicators proposed by numerous institutions or groups of experts. These indicators have been developed taking into consideration the legal and regulatory framework that are in force. However, their scope is not only to declare the mining company?s compliance with all legal requirements but also to represent its economic, environmental, and social performance. In this way, sustainability indicators allow assessment of a company?s capacity to produce commodities, to meet the environmental quality requirements and to contribute to a long-term economic, cultural and social development of the local communities.

Jan 1, 2007

SIR ROBERT HADFIELD, London, England (written discussion*).-We have in the past known so little about tungsten that an important paper such as Mr. Zay Jeffries contributes is most welcome. I have not much personal knowledge on the subject except as regards combinations of iron with tungsten. I put forward the results of my research on natural alloys in 1903,1 and so far as I know the facts there presented still stand. Singular to say, tungsten added to iron affects the electrical resistance less than any other added element. The following tables taken from research work by myself and Sir William Barrett may be of interest.

Jan 10, 1918

I trust you know now or will know by the time you havecompleted your degree and added a little on-the-job experience,how to make the product from the mine you are working for. Butyou may not know the process to turn it into dollars, which ofcourse will be the life blood of your company. I am not going topromise to turn you into super salesmen, but I hope I can takeyou beyond the level of believing that selling our mineralproducts is as simple as putting in it on to a train, waving itgoodbye and waiting for the cheque to turn up in the mailbox afew weeks later.

Jan 1, 1994

By J. H. deur Potgieter

This paper, 'A review of the biological treatment of cyanide-bearing waste water' discusses the necessity for the treatment of cyanide-bearing waste water with a view to the avoidance of environmental pollution, and the limitations of the available chemical and physical processes are referred to briefly. The sources of cyanide-bearing waste waters are mentioned. The mechanisms of production and utilization of cyanide by fungi and bacteria are discussed. The work done in connection with the biological removal and destruction of cyanide is summarized, the successes achieved are described, and the relevant processes are listed. In conclusion, some advantages of biological processes for the removal of cyanide are mentioned.

Jan 1, 1991

By D. S. Jacobus

It is proposed to give in this paper an estimate of the cost at which carburetted and uncarburetted water-gas will have to he sold, in order to compete successfully for steam-boiler use with anthracite coal. The following are analyses of the gas direct from the generator, and of the same after it has been carburetted for illuminating pnrposes. Per cent. by Volumes. I. 11. Uncarburetted. Carburetted. Nitrogen,.4.69 2.5 Carbonic acid,.3.47 .3 Ethylene,....... 0 12.5 Oxygen,....... 0 .2 Benzole vapor,...... 0 1.5 Carbonic oxide,.36.80 29.0 Marsh-gas,.2.16 24.0 Hydrogen,.52.88 30.0 100.00 100.0

Jan 1, 1889

By O. B. Hofstrand

Solid bodies mill float in a liquid by reason of lower specific gravity, or of peculiar form, or of repellent action towards the liquid which prevents them from overcoming the resistance of its surface-tension. To the last of these causes the flotation of ores is to be ascribed. Nearly all ores and gangues are specifically heavier than water, yet they do not behave alike in this respect, and they may be divided into two classes, those of floatable and non-floatable minerals respectively. Upon a close examination of these two groups of minerals we find that those particles that will float on the surface of

Jan 1, 1913

By R. A. Blake

Measurements of the quantity of xanthate abstracted from mineral surfaces and put into solution by an increase in the hydroxyl ion concentration were made. A residual xanthate concentration of 59.6 ppm was found in one case at a pH of 11.8. The abstracted xanthate is capable of acting as a collector on fresh mineral surfaces under proper conditions. It was learned that as the hydroxyl ion increased and the xanthate abstracted, the coarse particles lose their floatability first. A volume weight relationship based on percentage coverage was established and seems to offer a reasonable explanation of the cause of observed results.

Jan 1, 1973

By C. K. Nworu, L. O. Asuquo, C. O. Nebo

Selective flocculation studies of Agbaja iron ore with starch-type and nonionic polyacrylamide-type flocculants has been conducted to determine the effect of flocculant type. The results indicate that corn starch was slightly better than cassava starch in selectivity performance. Cassava starch was in turn better than Superfloc 16, while the poorest results were obtained with commercial starch. Sodium humate shows better dispersive capability, and thus enhanced flocculation results, than sodium silicate. Pulp pH affects the zeta potential, polymer chain configuration and hence selective flocculation. Overall results indicate that recovery and separation of this very fine grained iron oxide by selective flocculation is feasible.

Jan 1, 1995

By Alexander Filimonov, Yury Bloshteyn

Ventilation of gas mines keeps necessary sanitation and hygienic conditions for labor in mines and increases the safety by dilution and removal of hazardous and dangerous gases in accordance with the safety rules. Several different concepts exist at the present time to design mine ventilation control systems. But technical ideas have been developed inadequately and technological solutions have not been investigated experimentally enough to build a serviceable system. This paper presents a new concept of high- efficiency mine ventilation process control system (MVPCS). The methods of modern system engineering (Kalman, 1969) are used to establish its functional and algorithmic structure. A three level hierarchical principle of system building is considered.

Jan 1, 1991

By Robert A. Robinson, Steven R. Thompson, Harvey W. Parker

The Mt. Baker Ridge Tunnel, under construction in Seattle, will be the world's largest-diameter soil tunnel with an inside diameter of 19.2 m (63 ft) and an effective outside diameter of about 24.4 m (80 ft). The five-lane highway tunnel will be constructed using a "stacked-drift" scheme in which an articulated or "flexible" tunnel lining consisting of 24 concrete-filled drifts is constructed to form a horizontal compression ring followed by removal of the soil core. Geotechnical factors, including variable strength hard fissured soils, high horizontal stresses, potentially unstable sands, and prior slope instabilities, significantly influenced the innovative design and construction approach.

Jan 1, 1983

By H. M. Varner

Under sponsorship of the US Bureau of Mines and the Department of Energy, a new type of rotary rock drill was developed by The Bendix Corp. Originally developed for the production of holes for the installation of longer than seam height roof bolts, the flexible drill is a useful tool for many drilling applications. It allows hands-off or remote production of holes for increased drilling speed and greater operator safety in any strata suitable for rotary drilling. This paper discusses various applications and experience for the flexible drill system in coal, metal/nonmetal mining, and for civil engineering uses. Manual, remote control, and automatic roof bolter modules are also discussed.

Jan 1, 1984