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By Oliver Finn

Gold dredging has made such rapid strides of late and there is such a widespread interest in this branch of mining that I venture to contribute a detailed account of the way in which a Keystone driller was used by me in California to loosen, by blasting, a very tight gravel deposit, preparatory to dredging. There is a great difference between “cemented gravel” and “tight gravel.” A truly cemented gravel is not a dredging proposition, while the tightest possible gravel, where there is no cement, can be made easy working by the following method of blasting:

Jan 1, 2008

IN the underground department of a mine, we may fairly say that "good management is based upon three elementals: first, sound engineering; second, proper coordination and efficiency of every human unit; third, economy in the purchase and consumption: of supplies.This paper is practically an analysis of the second element; which stands out prominently as the most important in the winning of successful results. The human units are divided into officers and men. The officers intermesh. One man takes responsibility where another throws it down; incessantly new conditions are arising where they may be doubtful of their powers; and always, on account of the three shifts, varying methods of work are coming into conflict. This very often results in disorganization. What is most necessary to guard against this is an esprit de corps, which would influence officers to stifle personal feelings for the general welfare of the department, To secure co-operation and loyalty of the staff, the writer recommends for the mines of the field a system of profit-sharing. Distributed on a salary basis, together with liberal holidays (not less than three weeks in each year) on full pay...

Jan 1, 1912

By W Herrmann, R R. Large

Volcanic-hosted massive sulfide (VHMS) deposits in ancient, submarine volcanic belts of Australia include mound, lens and sheet-style Zn-rich polymetallic deposits, massive and disseminated pyritic Cu-Au deposits and disseminated, stratabound Au-only deposits. Variation in morphologies, metal ratios, volcanic environments and alteration features indicates there exists a spectrum of deposits from the classic VHMS model, to hybrids between VHMS-porphyry Cu and VHMS-epithermal end members. Zn-rich, polymetallic deposits form eitheron, or just below, the seafloor, whereas the Cu-Au and Au-only deposits form sub-seafloor by replacement of specific volcanic lithologies. Alteration zoned outwards from quartz -> chlorite -> sericite ¦ carbonate is typical of VHMS deposits across the spectrum. Quartz and carbonate alteration is dominant in the Au-only systems,chlorite alteration is commonly developed close to Cu-rich ores, and sericite and carbonate alteration zones are well developed in the stratiform Zn-rich ores. The most useful geochemical vectors for Zn-rich ores are the alteration index [AI=100(MgO + K2O)/(MgO + K2O + CaO + Na2O)], the chlorite-carbonate-pyrite index [CCPI=100(MgO + FeO)/(MgO + FeO + K2O + Na2O)], Mn content of carbonate, Mg/(Mg+Fe) ratio of chlorite,whole-rock Tl, Sb and Ba/Sr ratio, S34S of pyrite, and whole-rock S18O. The most useful vectors for pyritic Cu-Au ores are AI, CCPI, S/Na2O ratio, Na content of white mica, and Fe content of carbonate.

Jan 1, 2002

By Gartrell H. W

During investigations of the treatment methods for ore from the Bird-in-Hand gold mine carried out at Kalgoorlie and at these laboratories, it was found that excess alkali caused a lowering of extraction by cyanide, the cause of this being attrIbuted to the presence of a small amount of oxidised lead compounds in the ore. The subject has been discussed by various writers,3 but no satisfactory explanation of existing facts has been put forward. The experiments described in this report have been carried out with the object of obtaining some insight into the chemical reactions underlying the effect of lead salts and alkalis in cyanidation.The formation of cyanide-insoluble coatings on gold during roasting with lead compounds is well known, but the adverse effect of alkalis in cyanidation of ore is *This paper represents work done under a co-operative agreement between the Commonwealth Council for Scientific and Industrial Research and the South Australian School of Mines and Industries.Published by permission of the Mining Advisory Committee, Commonwealth Council for Scientific and Industrial Research.

Jan 1, 1935

By Met M. E

In choosing the subject for my address to you this evening I was actuated by the knowledge that in the past Australian metallurgical problems have been solved by the introduction of extremely interesting processes. Frequently such processes originated in this country, or at least were first adopted here on a large scale.Chronologically there comes to mind the application of chlorination to the Mount Morgan ores from 1888 onwards.Then the application of pyritic smelting to the Mount Lyell ore body in 1896, followed closely by the successful flotation of zinc blendÇ! at Broken Hill, about 1900, and the treatment of the refractory Kalgoorlie gold ores by roasting and cyaniding. With the development of the differential flotation process at Broken Hill came the production of a slime lead concentrate carrying zinc which necessitated the use of a high zinc slag in the lead smelting process. Although previously considered impossible, the necessarytechnique was successfully evolved at Port Pirie resulting in the accumulation of large tonnages of zinc-bearing slag as potential sources of that metal. The past twenty years have witnessed:-(a) The establishment of a flourishing iron and steel industry, with its attendant coking and by-product plant at two centres in New South Wales, namely, Newcastle and Port Kembla.(b) The establishment of an electrolytic zinc process at Risdon in Tasmania.*Presidential Address, Melbourne, 20th August, 1936.

Jan 1, 1936

By Ross Byron, Ken Roberts

"During the fall of 2001 a program was initiated to determine the feasibility of improving the metallurgy in the flotation circuit at the Penhorwood Talc Concentrator located near Timmins, Ontario. Bench scale testwork led Plant staff to believe that opportunities existed to improve the flotation performance. Pilot scale testing was then conducted using two vendors and their respective cylindrical type flotation cells to indicate where these opportunities existed.The results of the test program determined that the replacement of the existing flotation circuit (roughers, scavengers and cleaners) with new flotation cells could be economically viable. Justification was due to a reduction in installed horsepower, maintenance costs and a subsequent increase in recovery and throughput while maintaining product quality. Unforeseen benefits included reagent and air reduction, accurate level control as well as improved working conditions due to the removal of the antiquated equipment and ancillaries.This paper will detail the justification, installation and implementation of the new flotation circuit. A special emphasis will explain the hurdles encountered while trying to install and commission the circuit in an operating Concentrator with minimal interruptions to production.INTRODUCTIONThe Penhorwood mine and Concentrator is 28 yrs old and has gone through many ups and downs with different owners, Johns Manville, Steetley Talc and now Luzenac. It has also been expanded twice, with flotation and grinding capacity being added in recent years.All of the concentration is completed at the mine site while the fine grinding takes place in the Timmins micronizing plant.Luzenac’s Philosophy is to be the world leader in Talc production, technology and sales, having about 70% of the current world High Grade talc market."

Jan 1, 2004

By P. R. Clifford

Phosphogypsum is a byproduct of the manufacture phosphoric acid. There are approximately one billion tons of phosphogypsum stored in stacks in northern and central Florida. The Florida Institute of Phosphate Research (FIPR) is investigating potential uses of phosphogypsum. These include using phosphogypsum as a road base material, as a soil amendment in agriculture, as a daily cover in landfills, and as a construction material. The results of this research will be presented and will be discussed in light of regulatory barriers to the use of phosphogypsum.

Jan 1, 2002

By Fawad S. Niazi

Ever since the use of the cone penetration test (CPT) in geotechnical practice, attempts have been made to correlate CPT parameters with pile capacity components of unit end bearing (qb) and unit shaft resistance (fp), thus deriving multiple CPT-based pile design methods. These methods focus on "capacity" only without consideration to complete axial pile load-displacement (Q-w) response. Estimated capacities from these methods also exhibit considerable scatter without any consensus on their consistency. In addition, load-displacement curves obtained from axial load tests on highly expensive and extensively instrumented piles can exhibit different shapes. Nevertheless, a single value from the curve so obtained dictates the design capacity. Currently, there are at least 42 different criteria defining capacity with considerable variation in the values obtained thereof. The Randolph elastic solution, which provides a framework for analytical evaluation of pile load-displacement response, requires the profiles of soil stiffness. The fundamental soil stiffness defined by the small-strain shear modulus (Gmax) can be obtained from shear wave velocity (Vs) readings via seismic piezocone tests (SCPTu). The secant stiffness (G), which softens from Gmax corresponding to operational load levels, can be obtained by generating stiffness reduction curves from back analysis of load tests. Then, using appropriate G values, the Q-w curve can be defined for conditions similar to the database from the pseudo strain (w/d). Thus, a complete framework for optimal integration of SCPTu data, Randolph elastic solution and back-analysis of field operational stiffness can be established for complete axial pile foundation analysis.

Jan 1, 2011

By J. A. Finch, D. Lin

The robustness of the large-sections correction procedure, Hill's fast approximation, Barbery's correction and the PARGEN correction was examined by comparing their ability to reconstruct the true liberation distribution using sectioning data from computer-generated spheres. The results indicate that the flexibility of a correction procedure is related to the assumptions it makes about the continuity of the liberation distribution, locked-particle characteristics and ore texture. Overall, the large-sections procedure appeared to be the most generally applicable. The Hill fast approximation performed well, but this was probably because it partially incorporates the sphere model; the performance of the PARGEN and Barbery corrections varied from case to case.

Dec 1, 1995

By Thomas P. Mucho, Dennis Dolinar, Christopher Mark

Horizontal stresses are caused by global plate tectonic forces. During 1995 alone, they were largely responsible for closing two U.S. longwall mines. This paper presents six case histories from Pennsylvania. West Virginia, Kentucky and Alabama. In each case history, a mine encountered roof falls or difficult ground conditions in the headgate, caused by horizontal stress concentrations. The problems are detailed and the control measures adopted are described. In most cases, nearby longwall panels without stress concentrations were trouble-free. The paper also discusses detailed measurements made at two adjacent Pennsylvania longwalls. One headgate was oriented to avoid a horizontal stress concentration, and the other was not. Eliminating the stress concentration dramatically reduced roof support loads and roof deformation. The paper concludes that proper panel orientation and sequence is the key to maintaining headgate ground control. The optimum orientation is not parallel with the maximum horizontal stress, as previously thought but rather 200 in the stress shadow of the gob. Other stress control techniques, including artificial support, are briefly discussed.

Feb 24, 1997

A laboratory size solvent extraction apparatus has been constructed, which incorp- orates three stages of countercurrent extraction, followed by two stages of counter- current stripping. The model uses a gravity flow system from one stage to another and air lift pumps to recirculate organic and aqueous phases. A novel pump/mixer system is used to transfer solutions from the mixer compartments to the settler compartments. The model has proven valuable in the teaching of solvent extraction principles.

Jan 1, 1999

By Robert V. Berryhill

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

Jan 1, 1963

By G S. Anderson, N W. McDonald

"The IsaMill™ was originally developed to address liberation issues at Mount Isa Mines (now Glencore) operations, McArthur River and Mount Isa in the early 1990s. Following on from the industrial success at those operations, the IsaMill™ was commercialised. In the year 2000, Kalgoorlie Consolidated Gold Mines (KCGM) became the first external user of the technology with a 1.1 MW M3000 IsaMill™ installed to supplement the roaster capacity at its Gidji Processing Plant. The IsaMill™ was used to ultra-fine grind about 10 t/h of pyrite flotation concentrate to 10–12 µm prior to gold cyanide leaching. Based on the success of the Gidji installation, another was installed at the processing plant at KCGM’s Fimiston operation in 2002 in a similar duty.In 2014, a 3 MW M10 000 IsaMill™ was selected to replace the roasters at Gidji as part of the A$98 M emissions reduction project. The mill was commissioned in April 2015 at the design 30 t/h, allowing the immediate shutdown of the two roasters. Replacement of roasting with ultra-fine grinding completely eliminated air emissions at Gidji while maintaining overall plant production rates.This paper details the history of the IsaMill™ at KCGM from the original M3000 to the latest M10 000. It covers the basis of the process selection, circuit design, operating and maintenance data.Citation:Anderson, G S and McDonald, N W, 2016. IsaMill™ at Kalgoorlie Consolidated Gold Mines - from the M3000 to the M10 000 and Replacement of the Roasters at Gidji Processing Plant, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 29–38 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By P. M. Lin

A subsidence monitoring program over a longwall panel was established (1) to explore the impacts of dynamic subsidence on the ground surface and structures and (2) to correlate the movements between the structures and their corresponding points on the ground. The program consisted of a transverse line survey and a series of survey points around the structures on the ground surface and their corresponding survey points on the exterior walls of the structures. The vertical displacement of each point can be expressed as: where Si is subsidence at i point; Sif is the final subsidence at i point; F is face location in terms of distance from the i point and SD is seam depth. The development of subsidence can be divided into five stages. Damage to the structures starts at the beginning of the second stage, The maximum damage developed in the middle of the third stage. The relationship of the vertical displacement between ground surface and structures can be expressed as: G = aH + b where G is ground displacement, H is structures displacement, and a and b are constants. The relationship is linear. However, the strain is non-linear and more complicated because of the interaction of the ground surface and structure.

Jan 1, 1989

By J. Trckova, P. Prochazka

Physical models from equivalent materials satisfying geometrical and physical similarity have been constructed. A special technology of simulating the excavation of an opening at the front part of a tunnel and of measuring the deformation at the tunnel face was applied. The results yielded by the physical models were used to formulate constitution relations in the numerical solution. This coupled modelling enables us to predict the behaviour of tunnel structures more accurately. On a construit des modèles physiques, réalisés en matériaux équivalents et répondant aux conditions de ressemblance géométrique et physique. Sur ces modèles, on a utilisé une technologie intéressante de simulation du forage du tunnel et de la mesure de déformation du front de taille pendant le forage en progression. Les résultats donnés par les modèles physiques ont été utilisés pour formuler les relations de constitution dans la solution numérique. Une telle construction de modèles combinés permet de prévoir plus précisément le comportement de la structure du tunnel. Es wurden physikalische Simulierungsmodelle aus äquivalenten Werkstoffen konstruiert, welche die Bedingungen der geometrischen und physikalischen Ähnlichkeiten erfüllen. Bei diesen Modellen hat man die interessante Simulationstechnologie des Tunnelvortriebs sowie die Verformungsmessung beim Tunnelabbaustoß während des Vortriebsvorgangs eingesetzt. Die Ergebnisse der physikalischen Simulation wurden zur Formulierung von Konstitutionsrelationen in der numerischen Lösung genützt. So eine kombinierte Simulation erlaubt eine genauere Prognose des Benehmens der Tunnelstruktur.

Jan 1, 2003

By Michael L. Boucher

Copper and nickel sulfides occurring in the Duluth Complex of northern Minnesota were examined at the Bureau of Mines, A microscopic study was undertaken to determine the mineralogy and paragenesis of the ore minerals. Eighty-two samples were taken from one deep diamond drill core located near Babbitt, Minn. Modal analyses are presented for the Duluth Complex rocks and for the are minerals in the major mineralized zone. The major sulfide minerals are chalcopyrite, cubanite, pyrrhotite, troilite, and pentlandite. Results of this investigation suggest that the mineralization is related to the structural features of the enclosing rocks: pores, open fractures, and cavities. The pyrrhotite-troilite-pentlandite assemblage is believed to have formed from an immiscible sulfide melt, probably associated with the troctolitic rocks. Most of it settled to the very porous base of the Duluth Complex, and to the other porous zones near xenoliths; small portions were trapped higher in the section. A later introduction of a copper-rich sulfide melt replaced some of the pyrrhotite-troilite and oxides, and filled in the remaining open spaces and fractures in the Duluth Complex and those of the adjacent footwall rock.

Jan 1, 1975

By M. M. Gilkey

Pegmatites in Colorado occur for 150 miles along the Front Range (eastern-most range of the Rocky Mountains) from Larimer County on the north to Canon City on the south, and west into the Gunnison area. Many of the deposits have been classified. Minerals found in the various dikes include beryl, scrap and possibly punch mica, lithium-bearing minerals, columbite-tantalite, feldspar, and several rare minerals. Pegmatites are abundant in the Crystal Mountain district in Larimer County. About 5 miles south of the Crystal Mountain district and often identified with that district is the Hyatt pegmatite area. The Hyatt Ranch deposit has attracted particular attention because of the comparatively high beryl con-tent of the upper part exposed in opencut workings.

Jan 1, 1960

Drill cores from Section 62, New Broken Hill Consolidated Ltd., were used to study the petrology of rocks associated with the zinc lode. The distribution of the rock types in relation to the lode structure was determined. The distribution of the gahnite-bearing rocks was shown to be only partly conformable with the structure.It was concluded that large scale metasomatism was not widespread, that the rocks associated with the lode (except, perhaps, the quartz-gahnite-garnet rocks) were formed by metamorphism of sediments, and that rocks and lode were contemporaneously metamorphosed.INTRODUCTIONThis investigation was undertaken in order to study the rock types associated with the zinc lode of the Broken Hill orebody, and their relationship to the structure of the ore horizons. The work was confined almost entirely to the laboratory, and is therefore limited in its scope. It is hoped, however, that the information gained may throw some new light on the genesis of the lode.Certain inferences which are drawn from this work are at variance with the ideas of a number of earlier workers.In particular, the idea of large scale metasomatism developing many of the rocks associated with the lode, especially those containing manganese, is questioned. On the contrary, the rocks associated with the lode are more simply explained as highly metamorphosed sediments, in some cases modified by water introduced from surrounding rocks into zones of strong folding and faulting. As a corollary, a metamorphicsedimentary origin for the lode material, either as a concentrated sulphide deposit, or somewhat disseminated...

Jan 1, 1961

By C. C. Anderson

"While conducting investigations in connection with the helium program of the Bureau of Mines, the Cryogenic Laboratory has improved an apparatus for the rapid and accurate determination of the helium content of natural gas and gaseous mixtures derived from that source. The separation of helium is effected by the use of activated coconut charcoal which, when cooled to liquid-air temperatures, absorbs the nitrogen and other constituents of the gas, leaving the helium in a. spectroscopically pure state. This absorptive property of activated charcoal was discovered- by Dewar3/ in 1875. Several years later, while conducting their original researches on helium in natural gas, Cady and McFarland employed the charcoal method for the absorption and removal of the common constituents of natural gas and constructed an efficient apparatus in which this operation could be effected.4/ Shortly after initiating the government's helium activities during the World War period, the Bureau of Mines adopted, with Minor modifications, the Cady and McFarland apparatus and method of analysis. Seibel.5./ described this modified apparatus and method of procedure as part of a publication on helium-bearing natural gas. Subsequently, the Bureau's apparatus for helium analysis has been simplified and improved to facilitate more rapid and positive operation. The apparatus and method of procedure now being used by the Bureau of Mines Cryogenic Laboratory arc described in this paper.The personnel of the Bureau of Mines Cryogenic Laboratory has improved and brought the helium apparatus described herein to its present state of perfection. The writer's contributions have been-of minor importance, and he wishes to give the various members and former members of the laboratory staff full credit for the improvements they have made. He also desires to express his appreciation for suggestions and criticisms offered during the preparation of this paper to the following members of the Petroleum and Natural Gas Division, Bureau of Mines, which now includes the Amarillo Helium Plant and Cryogenic Laboratory: H. A. Cattell, chief engineer; C. W. Seibel, supervising engineer of the Amarillo Helium Plant; W. M. Deaton, chemist-in-charge of the Cryogenic Laboratory; and H. S. Kennedy.The quantitative determination of helium in a gaseous mixture is accomplished by the removal of the other constituents from the sample, either by chemical or physical Means, leaving only the helium which can be measured directly. Chemical methods, when applied to natural gas, require the burning of the hydrocarbons in oxygen, the, absorption of the resulting carbon dioxide in a caustic solution, the removal of the excess oxygen in a suitable solution such as an alkaline pyrogallate, and the elimination of nitrogen by sparking or by combination with hot calcium or magnesium.. Such procedures are very slow and tedious compared with the physical method which employs the absorptive property of activated charcoal to effect the separation of the other constituents from the helium."

Jun 1, 1934

COMPRESSED air is held in high esteem by the mining engineer as a medium for the transmission of power. The transmission, however, is accompanied by a high percentage of loss. Of the total work done by the steam cylinder'in compressing the air inthe air cylinder, less than 50% is ultimately utilized by the machines underground. These losses are due to its essential and inherent properties as a gas. One of the sources of loss is that due to transmission through the pipes which distribute the air from the receiver to the various places where it is used. As the capacity and economic design of air-compressing plant are influenced by this source of loss, it may be of interest to give an outline of how estimates may readily be made'in practice of thediameter of pipes, quantity of air discharged, and the drop in pressure occasioned.In hydraulics we have a general formula given M Rankine's "Civil Engineering" :It was suggested, the writer believes, in the first instance by D'Arcy, that this formula could be made to apply to an elastic...

Jan 1, 1918