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By Eren H

For a hydrocyclone of fIXed geometry, DC, Di, DO and ? are constants, the variable parameters affecting the performance are Qi, Fi, Du and H. (See Appendix 2 for definition of symbols).The relationship between d50c, Qi, Fi, Du and H gives models which can effectively be used for performance predictions. Such models have already been established by Lynch et al and by Plitt.These models have been tried in a limited manner under continuous operating conditions for on-line cowol. For on-line control effective and accurate instrumentation is required for which a new set up is proposed. Using this set up, a new model was established. A feature in this model is that deviations from the norm of operational parameters affecting d50c were considered. It is shown that these deviations generated by the disturbance of one or more of variations in the parameters, can be monitored by a computer and suitable signals generated to control servo mechanisms for restoring the required d50c value.The logic followed in developing the computer software is described and the application of the model is indicated.

Jan 1, 1990

By Jean-Marc Lulin

"Depuis 1906, pres de 130 gisements ont ere decouverts dans la inture archeenne polymetallique (Cu, Zn, Au, Ag) du nord-ouest becois. Une etude regionale du developpement du potentiel inier est presentee puis detaillee pour quatre secteurs: RouynDranda, Val d'Or-Malartic, Bousquet-Cadillac et Matagami.L' analyse est conduite a l' aide des parametres suivants: temps, ethodes de decouverte, profondeur des gisements et poids metal. ~~ courbes cumulatives illustrant le nombre de gisements decouverts fonction du temps montrent une forme generale en ""S"" dont les i'iations de pentes correspondent aux variations dans les taux de ~ouverte. Initiation, realisation et stabilisation des cycles de decourte sont ainsi mis en evidence. Deux ""bourns miniers"", de 1922 a ~5 et de 1955 a 1965, rassemblent 72 % des mines identijiees squ' a present.La plupart des mines sont trouvees en subsurface: 90% ont leur fmet entre 0 et 100 metres de profondeur dont 70 % entre 0 et 10 etres. Dans le temps, il y ad' abord recolte par prospection puis par fphysique et enjin, developpement progressif du potentiel en proeur avec des methodes composites. Environ 80% du poids metal extrait de 4 camps miniers, couvrant 8% de Ia surface regionale quelques gros gisements dominent /a production.Ces donnees permettent de proposer une nouvelle approche pour lysed' une region miniere:La distribution de Ia profondeur des gisements en fonction du temps est indicatricede /amaturite d' uncampminieret peut servir a evaluer son potentiel residue/.L' analyse des courbes en ""S"" permet d' extrapoler les taux de succes relies aux differentes methodes et met en relief le role crucial de I' innovation dans I' exploration.ABSTRACTSince 1906, some 130 deposits have been discovered in the Archean polymetallic belt of northwestern Quebec. In this paper, the development of the mining potential is analyzed at the regional scale and for the following mining camps: Rouyn-Noranda, Val d'OrMalartic, Bousquet-Cadillac and Matagami.The analysis is based on the following parameters: time, discovery method, depth and weight of metal extracted. Curves showing the cumulative number of deposits discovered as a function of time are ""S"" shaped with slope variations corresponding to changing discovery rates. Initiation, realization and stabilization of discovery cycles are thus well represented. Two ""mining booms"", 1922 to 1945 and 1955 to 1965, account for 72% of the mines identified to date.Most exploitable orebodies have been found near the surface: 90 %have their top between 0 and 100 meters, including 70% between 0 and 10 meters. Early discoveries were made by prospecting, followed by geophysics while the progressive development of the depth potential is being realized by a combination of methods. Approximately 80 %of the metal extracted comes from four mining camps which cover 8% of the area, but most of the production can be allributed to only a few large deposits. Based on these data, a new approach to the analysis of a mining region is proposed:1) The distribution showing deposit depth versus time is indicative of the maturity of a mining camp and can serve to evaluate its remaining potential.2) The ""S"" curve analysis can be used to extrapolate the success rate of a specific exploration method and also stresses the crucial role of innovation in exploration."

Jan 1, 1990

By M. K. Patel, K. C. Wade, M. Cross

In the past decade a good deal of effort has gone into the computer simulation of the heat distribution of pellet induration systems. The major uncertainty in the analysis of such systems is the gas flow distribution and, in particular, the role of leakage. Evaluation of the leakage into or out of a zone has proved to be very difficult, as has the cross-flow from one zone to another when adjoining zones have gas flows which change direction from up draft to down draft for example. This paper describes an initial model to calculate the gas flow distribution in a variety of practical situations of interest to those involved in pellet induration. The model is based upon a multiphase CFD code called CASCADE which is used in conjunction with the pellet induration simulation INDSYS.

Jan 1, 1990

By Donald A. Dahlstrom, Soumitro Nagpal, Timothy Oolman

Bacterial oxidation of a pyrite/ arsenopyritic gold-ore concentrate was carried out with continuous flow operation in 14 liter (1.4x10-2 m3) mechanically agitated reactors. 02 and C02 uptakes were determined at varying residence times. Bacterial concentrations were measured using a protein assay. A sharp optimum in biooxidation rates was observed with increasing steady-state residence times. Growth of the bacteria and biooxidation of the mineral were both shown to be strongly dependent on dissolved 02 levels in the liquor.

Jan 1, 1990

By Halagowder Devaraj, Mostafa Sheykhnazari, Veer P. Bhavanandan

"A sensitive colorimetric assay for detecting mucins and glycoproteins rich in 0-glycosidically linked saccharides is reported. The method combines the susceptibility of N-acetylgalactosamine terminating 0-glyco idically linked saccharides to P-elimination with the Morgan-Elson reaction for N-acetylhexosamines with free reducing ends. All mucin and mucin-type glycoproteins but none of the serum-type glycoproteins tested resulted in characteristic color production. All mucins tested gave linear responses in the range 5 to 200 ""g and the assay was also adapted to the microscale involving the use of 96-well microtiter plates. The microassay in which the volumes of samples and reagents are scaled down 2.5-fold was particularly useful in monitoring of mucins, in the presence of other glycoconjugates, in large numbers of samples obtained during fractionation procedures. Cesium chloride, cesium bromide, potassium thiocyanate, and various detergents do not interfere with the colorimetric determination. Guanidine hydrochloride, cesium triftuoroacetate, and B-mercap- . toethanol decreased color by 30 to 45%; however, the interference was not serious to prevent the use of the method for detection of mucins in their presence. The use of the method for the specific detection of mucin during fractionation by gel filtration and density gradient centrifugation of cystic fibrosis sputum samples is demonstrated. Mucins are an important class of biomacromolecules whose structure-function relationship is poorly understood (1,2). The investigations of mucins are hampered by difficulties in purifying these very large size molecules which appear to avidly bind other components of the mucus (3,4). One of the problems during purification is the specific detection of mucins. For example, during the various purification steps, the fractions containing mucins are typically detected by assaying for neutral sugars (hexoses) (5,6), for sialic acids (7), or for periodate oxidizable saccharide units (8). However, these methods are not entirely satisfactory because neutral sugars, sialic acids, and periodate-oxidizable saccharides are also components of other glycoconjugates. In addition, the neutral sugar and sialic acid measurements are also subject to interference from high levels of proteins and nucleic acids."

Jan 1, 1990

By R. Hogg, T. F. Dumm, L. G. Austin, M. Yekeler

"Dedicated to Professor Kurt Leschonski on the occasion of his 60th birthdayAbstractThe kinetics of batch grinding quartz from a feed of 600 by 425 Jim to a product of 80% less than 10 µm have been determined using screening and laser diffractometer sizing for size analysis. The specific rates of breakage decreased by a factor of about three when the material became less than about 100 µm in size, but the primary breakage distribution function also changed to give proponionately more fine material, so that the grinding efficiency expressed as the development of surface area (B.E:T.) per unit of energy input did not decrease. Analysis of the shape of the particles in the 2S x 38 µm size range showed that particles of this size produced by roll crushing or by 8 minutes of grinding of a 42S x 600 µm feed were not different but at long grinding times the particles were rounded. This suggests that the breakage mechanism changes to give more chipping and abrasion and less disintegrative fracture. As the material approached the ultrafine size range it adhered to the mill case and there was no further size reduction. However, a technique for striking the mill case to dislodge the particles was successful in allowing further grinding to 400Jo by weight less than 2 µm.1 IntroductionIt has long been known that it is difficult to accomplish ultrafme grinding in a tumbling ball mill. It has been reported [12, 13] that there is no further size reduction after some hours of grinding cement clinker in laboratory ball mills. Austin and Bagga (1] and Shah and Austin [16] have given an analysis of the kinetics of dry grinding in a laboratory ball mill, introducing the concept of a slowing-down factor K, which is the ratio of the specific rates of breakage at some long time of grinding to the normal specific rates of breakage. They showed that this factor decreased as fine material accumulated in the mill charge. Cottaar and co-workers [8-10] showed that the movement of solid in a dry laboratory ball mill was influenced by the fineness of the solid and by the presence of air, and that evacuation of air from the mill caused particle sedimentation and low rates of breakage.The concept of the slowing-down factor has also been used in wet grinding [17, 18]. At very .high slurry concentrations it appears to be correlated with a steady decrease of mill power caused by the build up of a layer of deposit sticking to the mill case. This reduces the effective mill diameter and, eventually, the balls start to adhere in the layer and centrifuge. A decrease of mill power always indicates less lifting and tumbling of the media and, hence, less breakage. However, slowing-down of breakage rates was also observed at lower slurry concentrations where there was no change in mill power."

Jan 1, 1990

By Chris McKee

Quartz has been of interest in occupational health for years because it can cause silicosis after prolonged exposure. New OSHA regulations (Air Contaminant; Final Rule) list perlite as a nuisance dust. They conclude that perlite is nontoxic when air-borne total particulate concentrations are 15 mg/m3 or below and when quartz content is less than 1% crystalline silica. OSHA has established an 8-hour PEL of 15 mg/m TWA for total perlite dust containing less than 1% quartz. OSHA has established a 5 mg/m3 TWA PEL for respirable perlite. These limits will protect workers from significant risk of eye, skin, or other physical irritation. This regulation is based on a Group 2A classification as a probable carcinogen in humans, at the 0.1% crystalline silica level, by the International Agency for Research on Cancer (IARC 1987a, b). IARC found sufficient evidence for carcinogenicity of crystalline silica in animals and limited evidence in humans. Perlite is not listed as a carcinogen by OSHA or the National Toxicology Program.

Jan 1, 1990

By Lang SC

The Broken River Province, in the northern part of the Tasman Orogen, is divided into the Camel Creek and Graveyard Creek Subprovinces. In the Late Cambrian to Early Ordovician, and again in the Late Ordovician, the northern part of the Tasman Orogen was probably a convergent margin with calc-alkaline volcanism. These episodes may have been separated by a passive phase in which quartz-rich flysch and tholeiitic volcanic rocks were deposited. Subsequently, in the Silurian, the region underwent extension forming a large turbidite basin which included the Camel Creek Subprovince and the Hodgkinson Province to the north. Melange is pervasive in the Camel Creek Subprovince which was folded twice in the Devonian. The melange may be related to thrusting accompanying D1. No rocks younger than Early Devonian have been recognised whereas, in the Hodgkinson Province, deposition continued until the latest Devonian. The Graveyard Creek Subprovince formed adjacent to the Camel Creek Subprovince, probably as a pull-apart basin on stable crust. The deformation history of the Graveyard Creek Subprovince contrasts markedly with that of both the Hodgkinson Province and Camel Creek Subprovince. In the Graveyard Creek Subprovince, melange is only present in Early Ordovician rocks. No major angular unconformities have been recognised in the overlying marine to non-marine sequence, which ranges from Early Silurian to Early Carboniferous. Several hiatuses and a slight angular unconformity, all within the Devonian, may be related to the major events in the Camel Creek Subprovince. A major deformation in the Graveyard Creek Subprovince in the Early Carboniferous had only slight effects in the Camel Creek Subprovince. Movement on the Clarke River Fault was probably an important influence on sedimentation and deformation in the Broken River Province.

Jan 1, 1990

By R. A. Pindred, M. P. Lam

Cyanide is a conventional lixiviant for gold extraction but its' toxicity is a major concern for the environmentalist. There are many alternative non-cyanide lixiviants, such as thiourea, thiosulphate, chlorine and hypochlorite etc., which may reduce environmental sensitivity. This paper will discuss the leaching characteristics of gold in hypochlorite leaching solutions. The dissolution of gold in a hypochlorite solution not only depends on the concentration of the hypochlorite but also on other variables, such as hydrochloric acid, sodium chloride and temperature. The dissolution rate of gold in hypochlorite solution is much faster than other lixiviants. Due to the interference of impurities, gold extraction from an ore under ambient conditions requires large quantities of reagents. However, refractory gold ores may be successfully pressure oxidized in an autoclave at reasonably low reagent levels. Gold extraction to the pressure oxidation leach solution is rapid and complete in one stage, thus eliminating the need for further cyanidation.

Jan 1, 1990

It is argued, that plate convergence, i.e. subduction, at other than right angles under a continental margin may lead to compensa-tional transcurrent faulting in the sialic environment. In this pro-cess the introduction of ultrabasic slivers, derived from the down-going oceanic crusial plate, along this fault may occur. This regi-me, both compressive overall and tensional along the transcurrent fault, will contain numerous indications for ongoing igneous and tectonic processes (such as volcanism, hot springs and frequent earthquakes).Examples for this scenario are California, the hinge between the Alpine- and Appennine orogens and the island of Sumatra.Igneous manifestations of subduction will be present both as inter-mediate intrusions and/or andesitic piles. The intermediate volca-nics may be intensely altered (chloritic, propylitic, argillic). Silice-ous breccias and banded chalcedonic sinters may be commonly found. This entire scenario is indicative for epithermal gold mine-ralisation.

Jan 1, 1990

By D Wilson, E Nagy, R A. Augsten, R R. Vandebeek, R L. Guilbeault

The Canadian Explosives Research Laboratory (CERL), is evaluating the status of the Schedule IV explosives container as it presently pertains to the industry. The Schedule IV container serves the same purpose in Canada as the IME 22 container does in the United States. That is, to transport detonators on the same vehicle which is carrying explosives.

Jan 1, 1990

The word governing derives from gubernare meaningto pilot a ship. Being inclined to metaphors, one could be forgiven to think that politicians act this verb and captain the Nation's ship into some definite course. In the case of at least the mineral resources industry, it seems that there are not many James Cook followers in our parliaments: Australia's approach to mineral and energy policy is often chaotic - witness the 1935 to 1961 ban on iron ore export-ing which prevented the development of a significant steel industry at time when the World was hungry for this metal, just to mention one amongst many other examples.The follies of Australia's mineral policies are well il-lustrated in the case of uranium mining. Although Australia had the Western World's largest economic reserves of uranium, it is onlythefifth producing nation and its uranium potential is largely unrealised. At the root of this situation are the interventionist attitudes and policies of successive Federal Governments which for more than four decades distorted the Investment decision and, in more recent times. discouraaed investment.

Jan 1, 1990

By Carl Hendricks, Malcolm Scoble

There currently exists no viable means of obtaining continuous feedback on blast efficiency. This paper describes the adaptation of a loading shovel to serve as a diagnostic tool to evaluate the success of ground preparation. Work undertaken in a large western Canadian open pit involved microprocessor-based instrumentation for the performance monitoring of an electric mining shovel. The monitored shovel responses proved to be reliable indicators of variations in muckpile diggability. This approach is considered to provide a very comprehensive survey of post blast conditions since such a shovel interacts which every cubic yard of a blast.

Jan 1, 1990

By H. Sevim

Three transportation systems in surface coal mines: 1-Truck Haulage, 2-Belt Conveying, and 3-Coarse-Coal Slurry Transportation are compared from the operations and cost point of Views. Computerized design and cost models were developed and cost data banks were compiled for each system. These models can be used to evaluate transportation systems and layouts that are practiced in most of the U.S. surface coal mines. A typical midwestern area strip mine was considered for illustration purposes. Sensitivity analysis on critical parameters such as production rate, transportation, distance, etc. was conducted and the outcomes are presented.

Jan 1, 1990

By Roger Lucas, Dale Nies

The McLaughlin Mine is an open-pit disseminated gold mining operation. Homestake Mining Company's approach to solving some of the blasting problems inherent to this type of deposit provide an interesting case history. Geology, although unique and site specific, is overall similar to other mines within the Western United States over-thrust belt and demonstrates an excellent example of the blasting conditions and requirements common to most of these operations.

Jan 1, 1990

By L. A. Wolff

"Second only to profitability (but not always), productivity is the most sought after measurement for any operation. Whether it is in mining, manufacturing, construction, etc. managers always strive to know how productive various plants are. Even the Federal Government publishes, on a monthly basis, the nation's factory productivity.Just what is productivity and how is it measured? This is an important topic that needs definition. There could be as many definitions as there are people who use it. In the mining industry, the problems of defining productivity would be analogous to the definition of equipment availability. Each mine uses its own definition to suit its needs. Webster's Dictionary primary definition for productivity is ""the quality or state of being productive,"" with productive defined as ""yielding or furnishing results"". This is a definition open to a broad spectrum of interpretation. A discussion of how productivity is currently used in the mining industry and an introduction to a potentially different approach to its measurement and meaning is outlined in this paper.Defining ProductivityTypically, mining companies track several productivity measurements. These are partial measurements and can include the following: tons per specific equipment class per hour, tons per man-hour, and tons per shift. None of these, however, track the over -all performance of an operation, that is, a unit of output per unit of input.For a mining operation, output can be defined as the ore for mill processing. Input includes the required components of production to get to the first step of processing.The Wesbter's Dictionary definition exposes a major fault with the popular conception of productivity. The critical issue of accountability is not addressed. Anyone can produce, but how effectively and efficiently are resources used? Quantifying an inclusive measurement is difficult. Statistics referring to an increase in productivity are often published. For example, the statement, ""gold productivity has increased by 10%"" has many potentially dangerous interpretations. One must ask, what does this statistic really mean? Did gold companies produce 10%” more gold? Were less manpower or equipment required to produce an equivalent amount of gold? Did ore grades increase resulting in more ounces of gold produced, etc. Obviously, production and productivity can have similar implied applications and meanings, but also two different, distinct meanings.To mitigate a problem like this, a standard needs to be developed within the mining industry. Because of varying ore grade, changing waste to ore ratios, different mining methods, etc. all of which have a direct impact on mining, development of a standard is difficult. Kendrick(1) discusses the use of Total Factor Productivity as a productivity measurement. Summarized, the total factor productivity measure is an indication of the change in efficiency in the use of basic labour and capital factors associated with an operation.This measurement has little meaning when calculated at a given point in time. It should be an on-going calculation, tracking an operation over a period of time, to evaluate trends. These trends can be used to determine if an operation's productivity is what it should be, and alert management to potential problems before they become major and adversely affect an operation."

Jan 1, 1990

Interest in mining narrow, vein-type ones has increased world-wide during the last few years despite the fact that prices of metals have not risen in proportion as production costs of mining, such as labour and energy.In many mines, where narrow ones are mined, the mining technique and equipment used have been poorly mechanized. The mining methods have been cut-and-fill or shrinkage stoping. Pneumatic jack-legs have been used for drilling and slushers have been used for loading.The methods that have been used can be called the "first-generation" methods.Work has been very hard for miners. It has been dangerous and exhausting.Production volumes of mines, and a s a result of that, also profits have been low.

Jan 1, 1990

By Harold L. Gibson, David H. Watkinson

"Volcanogenic massive sulphide deposits of the Noranda Camp cur throughout the Noranda Shield Volcano but are concentrated and along the margins of the Noranda Cauldron. The deposits are realized along synvolcanic faults that also accommodated subsince and controlled the location of eruptive centres. Deposits within e 3 000 m thick Mine Sequence formed during a period of active volcanism and subsidence coinciding with the onset of two cauldron subsidence cycles. The Noranda Cauldron was a restricted site of 10malously high heat flow and structural permeability that favoured e development of a high-temperature hydrothermal system. Metals may have been derived from leaching of aquifer rocks by convecting a water or directly from a shallow underlying magma chamber, now presented by the Plavrian Pluton, that was at its highest position !thin the crust during cauldron subsidence. The deposits formed rough a combination of sulphide precipitation from exhaled fluid td replacement at and below the seafloor in a manner analogous to ose on the modern seafloor.RESUMESi les dépôts de sulfures massifs volcano gènes du camp minier de ~uyn-Noranda sont présents dans les différentes parties du volcanluclier de Noranda, ils se trouvent concentres toutefois, en plus ·and nombre, sur le pourtour de la caldeira (cauldron) de Noranda. ~s dépôts sont localises le long des failles synvolcaniques qui ont cilite la subsidence et contrôle la position des centres d’éruption.~dépôts situes dans la séquence des mines (3 000 m d’épaisseur) sont formes durant un épisode d' activité volcanique et de subsiden qui coïncide avec l' amorce de deux cycles d' affaissement de la rldera (cauldron) de Noranda. Celle-ci Jut le site exclusif d’unflux : chaleur anormalement élevé et d’une perméabilité d’origine cucturale qui ont favorise le développement d’un système hydrothermal a haute température. Les métaux proviennent soit directement d’une chambre magmatique situee afaible profondeur, so it d’un lessivage des roches de l’aquifère par l’eau de mer circulant par convection. Cette chambre magmatique, représentée maintenant par le pluton de Flavrian, se trouvait à son niveau le plus élevé dans la croute au moment de l’affaissement de la caldeira (cauldron). Les dépôts se sont constitués par un mecanisme combinant remplacement et précipitation de sulfures à partir des fluides exhalatifs, au niveau ou au-dessous du plancher océanique, de la même manière que se forment de nos jours, les dépôts de sulfures massifs au fond des océans."

Jan 1, 1990

By A. J. Getz

The paper reviews the status of the major precious metals projects in Australia, Papua New Guinea, Indonesia, the Philippines, and New Zealand. The projects may be at the stage of exploration, development, operation, or expansion. The paper covers project location, reserves, method of resource exploitation, anticipated production, and other unique conditions.

Jan 1, 1990

Develop a simple and practical technique to measure in situ rock mass properties for realistic design and stability evaluation of underground structures. Background The Bureau of Mines has developed basic principles and techniques to determine in situ rock mass properties including Poisson's ratio, deformation modulus, and yield and failure strengths. An instrumentation package consisting of three pressure cells is installed in a single drill hole. Cell pressure response data are acquired and used to calculate and determine the rock mass properties. How It Works A test hole of BX size (approximately 5.7 cm) or larger is drilled to the approximate depth of the measuring point. The last portion of the test hole is drilled with precision bits to EX size (approximately 3.8 cm). The instrumentation package, which consists of one 3.8-cm-diameter cylindrical pressure cell (CPC) and two 5.7-cm-diameter cement-capsulated, flat borehole pressure cells (BPC's), is then installed. A complete history of cell response to changing strata loads is acquired on a continuous basis with a chart-type hydraulic pressure recorder. From these cell pressure data, Poisson's ratios, deformation moduli, and yield and failure strengths are calculated and determined.

Jan 1, 1990