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By John G. Henning

The Hoyle Pond underground mine is located in the Porcupine Gold Camp, 18 km east of downtown Timmins. Since the initiation of production in 1985, the operation has produced in excess of 1.9 million ounces of gold at a grade of 15 grams per tonne. Currently, Hoyle Pond ranks 8th in total ounce production for all past and present producing mines in the camp, with the highest head grade of any of the significant past, or present producing mines in Timmins. Cut and fill, shrinkage, longhole and panel mining methods are employed to excavate the narrow gold bearing structures. Using illustrative examples, this paper provides an overview of factors, such as geologic setting, rock mechanics challenges and mine infrastructure, which influence mine design at Hoyle Pond.

Oct 1, 2004

By A. A. El-Midany, R. M. Farag, A. M. Salem, S. E. El-Mofty

Bentonite represents one of the main players in the stability of the drilling mud. Its particle size and particle size distribution affect the physical properties of the drilling mud especially the rheological properties. Therefore, a specific particle size distribution was recommended by American Petroleum Institute (API) for use in drilling mud. To clarify the effect of individual size and size distribution, in this study, the bentonite sample was classified into different size fractions. Each size fraction was tested separately in terms of controlling properties such as filtration loss, plastic viscosity, gel strength, cake thickness, and packing density. The effect of each size fraction on the rheological properties of the suspension was correlated to the behavior of the whole particle size distribution in the bentonite sample. The results indicate that the coarser the particles, the higher the rheological properties; in this case, the API mixture is the highest. The filtration loss and cake thickness for the API mixture are lower than that of the individual size fractions due to its wider size distribution due to the filling of voids between larger particles with smaller ones, which lead to bed compaction and consequently lower fluid loss and cake thickness.

By Olga Frank-Kamenetskaya

The experimental results of study of atmospheric corrosion processes on Saint-Petersburg bronze monuments surface, received in situ and by means of simulating experiments, have been discussed. Influence of the time factor on corrosion film (patina) mineral composition has been analyzed. Direct dependence between patina mineral composition and environmental conditions has been proved. The sequence of patina phases crystallization has been established. Effect of the chemical composition and heterogeneity of artistic bronze and also monument surface structure on the rate of corrosion process has been regarded. The time variations of mass of the crystallized in the hydrochloric acid vapor phases have been investigated. The kinetic laws of their development at the initial stage of formation, indicating simple (non chain) reactions, have been revealed.

Jan 1, 2006

By Hsu-Hui Hsing

In several previous studies from this laboratory (1-4) the autophobicity concept of Zisman and co-workers (5, 6) has been extended to gas phase adsorption processes. Low molecular weight alcohols adsorb on silica or alumina to yield novel isotherms in that monolayer adsorption occurs at low relative pressures indicative of strong bonding, but subsequently multilayer adsorption is quite sparse and diminishes with molecular weight of the alcohol. Such isotherms fit no standard classification scheme, however, in the vacinity of monolayer coverage alcohol isotherms give an excellent fit to the Langmuir or B. E. T. , Type I model (7). Monolayer adsorption is relatively irreversible and it is thus possible to prepare these chemisorbed layers and perform subsequent adsorption studies thereon. All indications are that the adsorptive properties on such films is radically different from that on the underlying alumina (4, 8) and in one study finite contact angles for hydrocarbon fluids were observed. One perennial conceptual difficulty is that there is no observed upper bound to the adsorption isotherm which would be necessary for autophobic adsorption to occur. The cause for this has been studied, and it is currently believed that adsorption is complicated by reversible capillary condensation at contact points between powder particles. The evidence for this is that large particle powders give less "apparent" adsorption at high relative pressures and in one very tedious study adsorption on planar sheets, oxidized aluminum displayed similar reduced uptake at high relative pressures when compared with high specific surface area powders (3).

Jan 1, 1974

By R J. Norris, D J. MacKenzie

Gold-bearing veins have formed at a wide range of depths throughout the uplift history of the Otago Schist. The earliest gold mineralisation occurred during the later stages of Mesozoic metamorphism. This mineralisation was characterised by diffuse wall rock alteration with greenschist facies metamorphic or retrograde metamorphic mineral assemblages, and gold occurs in this altered rock. Quartz veins formed in .steeply dipping extensional fractures associated with this mineralisation type strike north to northeast. The Macraes mine exploits this deposit type. The present northwest strike of the mineralised zone at Macraes is a result of post-mineralisation deformation of the schistosity-parallel mineralised shear zone which hosts northeast striking extensional veins. This combination of schistosity-parallel shear zone and steeply dipping northeast striking veins may exist elsewhere in Otago, and this deposit type is most prospective. Steeply dipping quartz veins formed during post-metamorphic un-roofing of the Otago Schist strike northwest to west and occur as clusters of near-parallel structures in east and central Otago. These veins consist mainly of massive quartz, although some prismatic quartz occurs also. Breccia fragments in veins are common and these are generally silicified, with some gold. Wall rock alteration is negligible, and vein margins are sharp. A set of middle Tertiary veins occurs in northwest Otago. Most of these also strike northwest and dip steeply, but some strike northeast. These veins contain abundant ankeritic carbonate as well as quartz. The carbonate pervades adjacent wall rock as veinlets, but gold mineralisation is confined to veins. Quartz is commonly prismatic and vuggy, and contains gold, which is commonly coarse grained especially in silicified breccia zones. Associated veins contain stibnite. This vein type formed close to the paleosurface (>2 km). Mineralised veins in Marlborough currently strike northwest, but these have been rotated from northeast strike during Alpine Fault displacement of Marlborough from Otago. Some of these veins were formed under late metamorphic conditions and are similar to the north to northeast striking veins in Otago. As in Otago, this type should be considered to be most prospective if they have associated schistosity-parallel shears.

Jan 1, 2000

By Lewis Blanchard Brown

It is my purpose in the following paper to describe the south-central part of Siberia, with special reference to its geology and the mineral deposits. This region is known politically as the Achinsk and Marinsk districts of the Tomsk Government. It is situated among the Altai mountains, in. ]at. 50° to 55O n and long. 87O to 93O E., not far from the northern frontier of Mongolia, and is divided as follows: Mining Districts.—(1) The Tomsk mining district, including the political districts of Altai (belonging to the private crown lands of the Russian Emperor) and Marinsk; (2) the AchinskMinusinsk mining district, including the political districts of Achinsk and Minusinsk; and (3) the North Yenisei mining district, situated in the northern part of the Yenisei political district of the Yenisei Government. Fig. 1 is a map of the Tomsk mining provinces, showing the useful mineral-deposits, excepting those of gold, and giving the routes of the railroads and post-roads connecting the various districts. Political Divisions.—The Tomsk Government is sub-divided into seven " oojesdy " or districts, as follows: Barnaul; Biisk; Kuznetsk; Kainsk; Kolyvan; Marinsk; Narim; and the Altai district (private land, as above). The Yenisei Government is sub-divided into five "oojesdy" or districts, as follows : Erasnojarsk ; Kansk; Yenisei; Achinsk; Minusinsk. Concerning the geology of the region, in addition to the record of my own observations, references will be made to the works of earlier writers. These have been consulted for the purpose of comparison, as regards the districts which I have actually traversed, and for the purpose of completing my account of such portions as I have not been able to visit.

Jan 1, 1904

The Full Scale Model Roof Bolt Test System described herein was designed, fabricated, erected, and installed by MSA Advanced Systems Division for the U. S. Department of Interior, Bureau of Mines, Spokane Research Center. It was furnished under USBM Contract No. 50271014 and Modifications. The test system is intended for use by the Bureau of Mines to run comparison tests on roof bolt systems. The mine entry cross section is made from special concrete pillars and roof slabs. They are constructed within a steel beam frame with hydraulic operated cylinders to apply loads that simulate the action of mining overburden. The frame is designed so it can be disassembled for replacing the concrete in subsequent tests. A computer and data acquisition system is furnished to control the load application and measure and gather data.

Jan 1, 1979

By M. W. BERNEWITZ

AUSTRALIANS and New Zealanders, whose countries have respectively yielded gold to the value of £666,000,000 and £96,000,000, are taking full advantage of the current high prices for that metal. There is a marked activity in ordinary prospecting, geophysical exploration, further development of working mines and reopening of old properties, formation of new companies, installation of new equipment and processes, and expansion of operations generally. Australian gold production last year was approximately double the quantity of 1929 and its value three times as great, 1929 being the low of recent years. The 1933 production was about 821,000 oz. From New Zealand, 165,000 oz. was exported last year. Papua and New Guinea contributed slightly over 100,000 oz. What the future price of gold will be nobody knows, but, even if it returns to the former level, Australian producers are almost sure of 110 shillings an ounce until 1940 through the Commonwealth Government's Gold Bounty Act, at present temporarily and necessarily suspended from operation.

Jan 1, 1934

By A. M. Hanna

This paper presents the experimental investigation on the ultimate skin friction of batter piles. The model piles were pushed in medium dense sand deposits at different inclinations up to 30 with respect to the vertical and tested under axial compression loads. The decrease in the total skin resistance with increasing pile inclination can be explained in terms of the reduction of the ave­rage mobilized angle of friction between the pile shaft and sand. The analysis, which takes into account asymmetrical earth pressure distributions around the pile shaft, showed good agreement with experimental results.

Jan 1, 2010

By J. J. Jakosky

THE method of electrical mapping of oil structures to be described possesses certain limitations, as well as certain definite advantages. It, in common with other geophysical methods, is not a panacea for the solution of all subsurface geological problems. It operates on differences in electrical conductivity of the geological strata, whereas the other most-used methods operate on (1) differences in magnetic properties, (2) differences in gravimetric properties, or (3) differences in seismic properties. This modification of the resistivity method is therefore able to obtain subsurface information under conditions not favorable to the other methods mentioned. Where the other methods have been employed with ambiguous results it may act as a complementary method.

Jan 1, 1936

By C. -J. Rick

By implementing a converter downstream of the reduction furnace it is possible to broaden the product range significantly. The converter can also successfully be used to strip furnace slag from chromium oxide. Some process alternatives and their economical, practical and environmental implications are studied using process models developed based on UHT?s long experience in stainless steelmaking, stainless steel process control and charge chrome refining. Keywords Charge chrome, converter refining, ferrochromium products, process design.

Jan 1, 2010

By Scott, Turner

IN 1933, the monetary metals were produced in a ratio of 6.7 oz. of silver to 1 oz. of gold, the lowest relatively for silver since the period from 1851 to 1865. At the beginning of that period, the virgin placers of California -and Australia began producing almost simultaneously; in consequence, there was an abrupt fall in the high silver side of the ratio that had prevailed through the centuries after America was discovered. The output from the Comstock and other silver-bearing lodes, located a decade after this influx of new gold began, soon restored the production ratio to its former proportion, that is, a relatively large weight of silver compared to gold.

Jan 1, 1934

By G. I. McPhail

The authors have conducted several investigations into the prediction of the beach profile of high-density tailings and have found that there are a number of important considerations that need to be taken into account over and above the reliability of the beach profile prediction methodology. These considerations relate to the chemistry of the slurry and specifically the influence of pH and flocculation, both of which have a significant influence on the rheology of the slurry at the discharge point. A number of examples are discussed and a potential testing protocol that will assist in assessing the influence of chemistry ahead of the beach profile predictions is presented. A methodology for assimilating the results of the testing into the likely field situation is discussed, and suggestions are made on application of the results in beach profile prediction. The suspected influence of residual flocculation on the stratification

Jan 1, 2012

By Hiroshi Yamazaki

The paper describes prediction, control and validation of face pressures, and special TBM features for the bored tunnels of the New Metro Rail City Project, Perth, Australia. The selected EPB-TBM passed below a heritage bridge and the operational Perth Railway station in ground conditions consisting of fully saturated uniform sand combined with shallow overburden and a horizontal alignment radius of only 135m. Therefore, strict control of volume loss, TBM operations and ground movements was vital requiring continuous evaluation and adjustments to TBM operation parameters. The paper discusses the effectiveness of applied TBM face pressures and the used foam/polymer soil conditioning which was measured against achieved volume loss and the predicted range of ground settlements.

By K. Sugawara, Y. Hirakawa, A. Sato

The rock mass properties such as deformability and permeability are highly dependent on the existence of cracks. The Ratio of Crack Opening Dependency (RCOD) was proposed as a new index to evaluate the deformability of infinite jointed rock mass. The RCOD is defined as the ratio of total amount of crack opening and the total deformation of jointed rock mass. The theoretical relation between the RCOD and the effective compliance of jointed rock mass is discussed and confirmed through two-dimensional numerical analysis by the SC-DDM, together with the applicability to the rock engineering. Les propriétés de masse rocheuse telles que la déformabilité et la perméabilité sont très dépendantes de l'existence de fissures. Le rapport de dépendance d'ouverture des fissures a été proposé comme un nouvel index d'évaluation de la déformabilité de masse rocheuse à assemblage infini. Le rapport de dépendance d'ouverture des fissures est défini comme étant le pourcentage de quantité totale d'ouverture des fissures et de déformation totale de la masse rocheuse assemblée. Le rapport théorique entre le rapport de dépendance d'ouverture des fissures et la compliance efficace de masse rocheuse assemblée sont traités et confirmés au travers d'une analyse numérique à deux dimensions par SC-DDM en même temps que l'applicabilité à l'ingénierie des roches. Die Felsmasseneigenschaften wie Verformbarkeit und Durchlässigkeit sind hochgradig abhängig von dem Vorhandensein von Rissen. Das Verhältnis der Riss-Öffnungsabhängigkeit (RCOD) wurde als neuer Index der Verformbargkeit von infinit zerklüfteter Felsmasse vorgeschlagen. Der RCOD wird als Verhältnis der Gesamtmenge der Rissöffnungen und der Gesamtverformung der zerklüfteten Felsmasse definiert. Die theoretische Beziehung zwischen RCOD und der effektiven Verformbarkeit von zerklüfteter Felsmasse wird diskutiert und durch zweidimensionale numerische Analyse mit SC-DDM bestätigt, zusammen mit der Anwendbarkeit auf Bergbautechnik.

Jan 1, 2003

By Z. Leng

"After detonation of the explosive, the final blast-induced damage area around the blast-hole falls into three categories, namely crushed zone, fractured zone, and elastic deformation zone. This paper presents a modified model to calculate the size of crushed zone around a blast-hole in drill-and-blast, with the hoop compressive stress and cavity expansion effect taken into account. The material in the crushed zone was assumed to be a granular medium without cohesion, but with internal friction. On this basis, the formula for crushing zone radius was derived. The proposed approach was verified with tests reported in the literature and the simulated results from SPH-FEM coupled models. A full statistical analysis was also carried out, and the predicted values were found to be in better agreement with the test results compared with other models. A sensitivity analysis of the modified model showed that the size of the blast-induced damage area is mainly affected by the following factors: rock mass properties, in situ stress, and borehole pressure. In particular, the roles of borehole pressure and in situ stress are discussed. Finally, suggestions are made on how the size of the crushing zones can be decreased. IntroductionOver the past decades, drill-and-blast has become the most commonly used technology in rock excavation. It is well known that in rock mass fragmentation with explosives, the annular rocks around the blast-hole are converted into fines. The formation of these fines consumes a significant part of the energy of the detonation, which in general is ignored in the determination of the efficiency of detonation (Glatolenkov and Ivanov, 1992; Furtney et al., 2012). Many studies show that only 20–30% of the total explosive energy is effectively used in fragmenting the rock, and up to 50% of the energy generated by conventional charges is wasted in overcrushing of the crushed zone and the inner part of the fractured zone (Ouchterlony et al., 2004; Sanchidrian et al., 2007). How to control the crushed zone to enhance the effective utilization of explosive energy, reducing the unit explosive consumption and the engineering cost, is therefore of great significance."

Jan 1, 2016

By Jochen Petersen, Diane Taggart

"At an average of 90.3% (for the period of 1 January 2009 to 30 September 2011), Zincor’s zinc recovery was well below the industry standard of 96%. The losses through the residues, in particular the iron residue, were the biggest contributors to the overall zinc loss. It was believed that this loss could be decreased with the implementation of seed recycling. A plant trial was run to test the implementation of a seed recycle. The rate of seed addition through recycle was increased over a 4-week period. The presence of seed decreased the insoluble zinc loss by providing additional surface area for iron to precipitate onto, and reducing coating of unleached neutralising agent. The soluble zinc loss was also decreased at low and moderate seed recycle volumes. The improvement was attributed to agglomeration growth of the recycled particles, which improves the dewatering characteristics of the precipitate. In contrast, the soluble zinc loss increased at high seed recycle rates. This result was attributed to particle crowding and a low wash ratio.INTRODUCTION The Zincor refinery, which closed in December 2011, was situated just outside of Springs in the Gauteng Province of South Africa and employed the conventional Roast-Leach-Electrowin process, which accounts for 75 to 80% of the annual primary zinc production in the world. The refinery fed up to 220 000 t/a of zinc sulphide concentrate. The major portion of the raw material was sourced in Southern Africa from the Rosh Pinah and Black Mountain mines. Between 20 000 and 40 000 t/a of material was imported to make up the deficit and to improve the grade of the feed material. The iron contained in the zinc concentrates, at an average of 6.03% (for the period of 1 January 2009 to 30 September 2011), resulted in the formation of zinc ferrite during roasting, which is insoluble under atmospheric leach conditions. At Zincor, most of the zinc ferrite was dissolved in the residue treatment plant at elevated temperature and high acid strength. The leach liquor from this aggressive leach contained between 15 to 30 g/L of iron, mostly in the ferric form, and was known as the hot iron solution (HIS). The presence of iron in the liquor had an adverse effect on the zinc operation, particularly on the current efficiency in the electrowinning circuit. Therefore the iron needed complete removal."

Jan 1, 2016

By J C. Volkwein, A D. A Hansen, E Sarver, C Barrett

Ensuring that diesel particulate matter (DPM) levels in underground metal and non-metal mines are maintained below statutory limits is an essential requirement of mine ventilation systems. However, despite the cost of providing ventilation, air ventilation rates are usually based upon models, assumptions, or measurements integrated over long durations rather than actual need. Real-time measurement of DPM, interpreted in terms of mine activity schedules, can offer better ventilation management to keep DPM within regulated levels while controlling costs. This work presents data from three demonstration sites with in-mine applications of an environmental particulate sensor that measured black carbon (BC) as a surrogate for DPM.Aethalometers are a class of environmental monitors that measure the light absorbance of aerosol particles at several optical wavelengths. A model AE33 Aethalometer was operated in three separate mines for periods of two weeks, three months, and seven-plus months, and the data was reported in real time as a concentration of BC. Concentration of aromatic organic compounds, which can indicate other forms of combustion, was also reported. The data was used to:- measure the relative efficiency of a new scale-model DPM air scrubber- determine if ventilation could be reduced in a shotcrete loading facility without compromising air quality- evaluate diurnal and weekly DPM levels in a large-entry stone mine. Instrument data were displayed locally and stored for later downloading in all cases. In one mine, the instrument was connected to a local controller, and in another it was connected to the mine’s underground network so that DPM data was presented in real time to a display in the mine ventilation engineering office on the surface.The results showed that the air scrubber removes from 82 per cent to 95 per cent of the DPM; that DPM produced during shotcrete loading is only a minor part of overall DPM levels; and that wide variations in DPM levels exist in the limestone operation. The DPM monitor operated continuously for extended periods in these underground environments. The only maintenance required was the routine replacement of filter tape, typically on a two-week schedule. A sample diluter, which is currently being tested, could extend the intervals between filter changes. The real-time data output of the Aethalometer is appropriate for direct integration into ventilation-on-demand control systems.CITATION:Volkwein, J C, Barrett, C, Sarver, E and Hansen, A D A, 2017. Application of an environmental ‘black carbon’ particulate sensor for continuous measurement of DPM in three underground mines, in Proceedings Australian Mine Vent Conference 2017, pp 143–150 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By E. G. King

The Bureau of Mines made experimental determinations of the heats of formation of forsterite and chrysotile at 298.15° K. The heat capacities of two polymorphs of serpentine, chrysotile and antigorite, were measured over the temperature range from 50° to 298° K and the entropies at 298.15° K were evaluated. The heat content of antigorite above 298.15° K was measured to 850° K. These thermochemical data were combined with other pertinent data to give heat and free energy of formation values at high temperatures. Free energy values are given for the reaction, forsterite + water = brucite + serpentine at different temperatures and pressures.

Jan 1, 1967

The uptake of zinc, lead, and copper by the flora of the Tui Base Mine area near Te Aroha is described.Vegetation and soil samples were taken from two traverses across the Raukaka Lode. Results. after statistical analysis, indicated that Beilschmiedia tawa was a suitable species for biogeochemical prospecting for lead and that SchefJlera digitata was satisfactory for zinc.The tawa showed a negative anomaly for lead over the vein itself but not over the adjacent dispersion halo. It was concluded that lead concentrations greater than 230 p.p.m. in the wood ash of the tawa and zinc concentrationsgreater than 540 p.p.m. in the leaf ash of S. digitata denoted threshold values for anomalous mineralization in the soil beneath. Although both species contained copper, neither indicated a soil anomaly for this element.

Jan 1, 1969