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By Pierre Sauvé, Alex Makila

"The Camflo stock of porphyritic quartz syenite is an irregular pipe-like body 200 metres in diameter injected along the axial plane of an E-W trending F2 fold, near the contact between the. Kewagama and Malartic groups. The stock plunges 55° to the NE, almost parallel to the fold axis. The stock, exhibiting pervasive, weak cataclasis with numerous, locally auriferous quartz veinlets, is cut by minor faults striking WNW and dipping about 45°NE.Two types of gold ore are distinguished at Camflo: ""porphyry"" ore and ""fault zone"" ore. ""Porphyry"" ore, accounting for 90% of the gold produced, forms wide zones within the stock. The zones are irregular in shape but tend to be oriented E-W in plan view (on a horizontal plane) and are elongated paraliel to the plunge of the stock. These zones are more abundant in the northern part of the stock. Differences between ore and barren porphyry are not obvious. ""Fault zone"" ore occurs outside the stock along minor faults, particularly in differentiated sills offer rodiorite and felsic granophyre. Gold grade is roughly proportional to the pyrite content which in turns depends in part on the original magnetite content of the host rock. Although both types of ore show some correlation between Au and S, the Au/S ratio is considerably higher in porphyry ore.The bulk of the gold is in quartz syenite and in felsic granophyre, the most brittle lithologies at the mine. Presumably, the vertically continuous, pipe-like stock, made up of shattered rock, provided the main channelway for the ascending mineralizing solutions."

Jan 1, 1990

By B. Tougas

Recycling of titanium represents an important economic activity due to high cost of the material and the amount of returns of machined parts which represent the bulk of finished titanium products (typical "buy to fly" of 10 in the aeronautic industry). In the present work, the metallurgical quality of 76 mm in diameter and 20 cm ingots poured in coated graphite mold will be assessed against the nature and condition of application of 4 coatings namely aluminum oxide, yttrium oxide, zirconium oxide and zirconium oxide with 4% aluminum oxide. The metallurgical quality has been evaluated in terms of alpha case thickness, microstructure and composition. Microhardness from surface will be assessed against casting conditions. Least square regression analysis have been use to optimize casting conditions.

Jan 1, 2011

By N. R. Paterson

"More than a dozen AEM systems are currently being used in the routine exploration for massive sulphides. The systems differ from one another in minor respects, but fall into four main categories: rigid-coupled in-phase/quadrature systems; towed-bird, single-component systems; differential systems; and passive systems.Although field tests are important in demonstrating the performance characteristics of the AEM/airframe assembly (noise-levels, coupling effects, etc.), more meaningful evaluations can be made through physical or computer modelling. The latter approach has been used to compare the response of twelve AEM systems to both vertical and horizontal sheets, simulating a large orebody and a con-ductive overburden respectively. The effects of height changes are also studied.The results demonstrate that each AEM system has its own particular advantages and disadvantages. The relative importance of these is a matter for the geophysicist to judge, on the basis of specific geological and environ-mental information. Data currently available on AEM systems are adequate to permit an objective evaluation of the systems for a particular exploration program."

Jan 1, 1971

By Eduardo A. Pérez, Alejandro R. Alonso, Rosa María Luna-Sánchez, Gretchen T. Lapidus

Rare earth elements have been widely used in various sectors, from the aerospace and steel industries, to electronic applications, particularly in displays and batteries for portable devices. The high demand for newer and better equipment, such as cell phones, tablets and lap tops, has increased the consumption of the rare earth elements and at the same time the need for its recovery from electronic wastes. For that reason, the recycling of batteries is important, principally the Ni-HM batteries, due to their elevated content of rare earths elements, in addition to the high concentrations of cobalt and nickel. The current processes are based on dissolution in strong acid solutions (sulfuric acid concentrations from 2 to 4 mol/L), and temperatures from 30 to 90°C. In the present work, electrodes from spent Ni-HM batteries were leached using 1 mol/L H2SO4, in the presence of ozone as the oxidant, where recoveries of 96% for La, Ce and Nd were obtained at room temperature. The separation of Ni and Co from the leach solutions was performed using an electrochemical reactor, after which rare earth elements were precipitated, obtaining a mixture of its hydroxides with impurities below 1%, according to EDS analysis.

Jan 1, 2014

By B. F. Osborne

"A new sensor cannot be considered in isolation from the process in which it is utilized. This paper, describing an on-stream particle size analyzer, therefore gives considerable emphasis to the slurry handling techniques employed to ensure that the instrument is presented with a representative sample. A new sampler is described, which continuously abstracts a small, representative sample from a closed pipeline containing a flowing slurry. This sample is then diluted, thoroughly mixed and pumped to a head tank, from where a continuous stream is fed at a constant rate to the size analyzer. Data are presented to show that particle size segregation is minimal throughout this sampling and sample preparation. A continuous particle size analyzer based on a separation principle is described, and the basic parameters of size distributions, and how they relate to this particular instrument, are considered. Typical results are given. An electronic system is presented which accepts the basic sensor outputs, and converts these to a particle size signal suitable for process control. Finally, the use of an inplant computer to process the sensor signals to obtain a particle size signal is briefly considered."

Jan 1, 1972

By A. T. Jakubick, A. MacG. Robertson

This paper reviews key issues related to the placement of dry (soil) covers on extremely weak, compressible fine tailings. The design and construction of soil covers on such tailings often presents a formidable challenge to the geotechnical as well as the environmental engineer due to the low shear strength, poor traffic ability, and high settlement of under consolidated tailings at the time of reclamation. The geotechnical issues to be considered include: (1) consolidation of near-surface tailings to achieve strength gains, improve traffic ability, and allow safe placement of initial cover layer; (2) stability of tailings slopes during dewatering of tailings ponds and/or cover placement; and (3) long-term settlement of tailings and its impact on cover integrity and final surface shaping. The environmental issues to be considered include: (1) management of contaminated (free) pond water; (2) management of contaminated pore water expelled during tailings consolidation; and (3) management of (uncontaminated) surface water on top of the cover. This paper summarizes recent experiences gained in a large uranium tailings reclamation project. It is concluded that a careful consideration of both geotechnical and environmental issues during the planning stages greatly reduces the costs and environmental risks associated with fine tailings reclamation.

Jan 1, 2000

By E. M. De Souza, A. M. Coode

"Since potash was discovered substantial rock mechanics research has been done to develop the technology needed to cope with the unique conditions in Saskatchewan mines, to assure general mine safety and to assess the problems associated with mining potash at depth.The practical result of this research was the development of multiple entry systems incorporating yielding pillars for access ways and the chevron type layouts for production panels. These developments proved the viability of extracting potash from between 950 m and 1100 m depth using a high degree of mechanization. High extraction ratios could not, however, be achieved using the developed technology.The presence of a competent salt back is critical to mining the potash, and underground practice is governed by the presence of anomalous geological zones. These factors may be associated with the occurrence of brine inflows. One potash mine in Saskatchewan ceased its underground operations and was closed due to flooding of the entire mine. Two other potash mines in Saskatchewan had significant brine inflows. The costs involved in brine pumping, equipment relocation, bulkhead construction, grouting, and in auxiliary operations can run into the tens of millions of dollars.At Central Canada Potash, the use of stress relief and yielding pillars in the design of the mining layouts has resulted in over-all stable underground excavations and safe mining practices. There are two types of production room s, the chevron and the hybrid, which result in a planned block average extraction ratio of 35010. Mining activity has resulted in brine ingresses in two areas, and additional operating costs have been incurred over the years. These mining areas have demonstrated abnormally high closure rates, and rapid back deterioration. A program was established in those two areas to ensure the practice of safe mining procedures.The short-term perspectives inherent in the program included the elimination of all uncertainties associated with the possibility of an increase in brine inflow leading to flooding, the elimination of the abnormal ground behaviour and ground deterioration in the inflow areas, and the reduction of the long-term adverse effects of mining on regional mine stability. The program was also designed to provide means for developing alternative safe mine layouts which would improve the exploitation of potash resources. Details of the extensive work performed during the program are found elsewhere (E. De Souza, 1988).Grouting and salt backfilling are viable techniques to control brine inflows in underground excavations in potash mines. Detailed instrumentation of the backfilled test areas provides information on the long-term behaviour and effectiveness of the grout/backfill system, allowing for rational decisions on the complete abandonment of these mined out areas, thus resulting in considerable operational cost savings.This paper is presented in two parts: the first addressed the problems of diamond drilling , grouting and backfilling in Panel 209 and the second, addresses the problems of instrumentation and rock mechanics."

Jan 1, 1990

By G. A. Vissac

IN THE preliminary design of a coal washery, the most important factor to evaluate is the ash content of the final product. The ash content permissible may be imposed by market demands, but, in the final analysis, sooner or later - as most consumers today are buying coal on a 'heat value' basis - the coal operator has a certain margin of latitude. and the ash content of the coal to be delivered can be determined on the basis of maximum returns and highest profits. A few years ago, the most desirable separation was selected on the basis of the plus-minus 0.10; that is, the most desirable gravity of the separation was selected at the point showing a minimum amount of near gravities in the raw coal. The reason for this was an expected wide error over these near gravities. Today with the recent development of cry accurate, automatically controlled cleaning apparatus, a much larger latitude is possible, and the most desirable gravity of separation can be selected, almost exclusively, on the basis of the economic factors involved. To illustrate these new methods of investigation we shall give two examples, based on actual coals from the western United States.

Jan 1, 1957

By L. A. Clark, G. H. R. Burrill

"Most unconformity-type uranium deposits in Saskatchewan occur within a few tens of metres above and/or below the basal unconformity of the 1,45-b.y. Athabasca Sandstone. Graphitic basement rocks coincident with post-Athabasca faulting or brecciation at or near the unconformity are important in localizing uranium deposits which form as tabular, ribbon-like bodies with grades averaging over 2 per cent uranium and containing up to 50,000 tonnes UJOs. Some of these deposits have similar contents of nickel and arsenic.In the genetic model proposed to explain these deposits, traces of uranium were leached from the sandstone and weathered basement rocks by oxidized formation waters sweeping through the sandstone and along brecciated faults. Over basement meta-petites, a thick clay regolith adsorbed uranium from the solution. Thus fixed, the uranium was reduced through an indirect reaction with graphite, possibly involving methane. The clay mineral surfaces were thus continuously cleared to allow further adsorption. Basement faults localized along weak graphitic units were re-activated, offsetting the sandstone formation, probably at the time of an early uranium deposition about 1.2 b.y. ago, and served as vents for spent ore solutions. Fluid convection was induced by topographic relief and/or crustal heating from radioactive decay in basement plutons or mantled Archean domes with uranium and/or thorium contents a few ppm above those of adjacent rocks. Heat from radioactive decay within the incipient uranium deposit would develop in about a million years. The self-generating convection cell would continue uranium deposition until all permeability was plugged by minerals. In some instances, convection was re-initiated after subsequent faulting and brecciation. While some deposits were further enriched, heavy flows of oxidized fluids re-dissolved and partially depleted other uranium deposits.The East Alligator Rivers uranium deposits in Northern Territory, Australia, occur within Middle Proterozoic quartzchlorite and quartz-muscovite schists overlain by sandstone. Highest grades occur in silicified breccias where carbonate beds were leached out. Mineralization ages are both pre- and post-Kombolgie Sandstone, but, to date, no significant uranium mineralization has been encountered in the sandstone. There are many general similarities with Saskatchewan deposits, but important differences in detail."

Jan 1, 1981

By Michael K. O’Leary, William D. Coplin

"Risks from political instability and government policies restricting equity ownership, local operations and transfers of payments affect the profitability of foreign mining ventures. More than seat-of-the-pants judgments and old-boy networks are required to anticipate these risks and to take actions appropriate to offsetting them. A system for making political forecasts, called the Prince System, and a series of charts relaying risk s to a production of key minerals will be presented.IntroductionFirm s with extractive operations outside their home country do not have to be told that political stability and government decisions play a big role in the success o f their operations. The takeover of copper firm s in Chile during the Allende administration in 1971 and the recent decision by Venezuela to reduce Reynolds Metals equity share in a smelting operation from 50% to 28% are two examples of hundreds of events that have determined the profitability of extractive operations over the past decade. Both risks and opportunities for international firms seeking to produce and market raw materials are heavily affected by political conditions. While news of political events travel much faster than in the past and host governments are more clever in shaping the risks as well as the opportunities, politics has always been part of the mining business.What has changed is the need to be more systematic in approaching the assessment of political conditions and how it affects business. The increasing costs of extractive operations, the need for long-range planning, the importance of financial arrangements and the world-wide scope of man y firm s' activities require that the assessment be updated continuously and be comparable across different countries and different types of investments. Political risk analysis, the assessment o f macro-political changes and specific governmental decision s on the operations of extractive industries needs to become as systematic and integrated into corporate decision -making as economic analysis has become over the past two decade s."

Jan 1, 1983

By Wang Wenqian, George W. Poling

"Devices and flowsheets for recovering fine placer gold are reviewed. Inefficiencies of gravity processing techniques are documented and discussed. Prospects of combining gravity and froth flotation techniques are presented. Possibilities of using other separation techniques, such as magnetic and electrostatic devices are also discussed.IntroductionSeveral new methods for beneficiating different types of placer ores have been developed in the last two decades. Improved efficiencies in the recovery of fine particles have been achieved by improving gravity flowsheets and machines as well as by developing multiple treatment techniques involving flotation, magnetic and electrostatic separations. Placer gold processing, however, has been an exception to some extent. Gravity concentration using riffled sluices accompanied by mercury amalgamation is still the main method in use today. Because of this, the recoveries of fine gold and the other associated values are often similar to those achieved several decades ago. For example, very few sluice systems recover significant placer gold finer than 100µm in size.Only a few proposals for using alternatives to simple gravity methods for recovering fine placer gold can be found in the published literature. The fixed, low gold price discouraged research in this field for many years. Development of more efficient processes has not kept pace with the recent rapid escalation in the price of gold. Froth flotation for saving fine placer gold might now prove economic, for example. This paper reviews literature published on the recovery of fine placer gold over the period 1907 to 1980. Suggestions for improving the performance in this field, based on the authors' current testwork, are also presented."

Jan 1, 1983

By T. L. McCall

AUTHENTIC records show that coal mining in Cape Breton dates from the year 1720, when the French military authorities obtained coal from what is now known as the Blockhouse seam, in the Morien district, for use at Louisburg, where the fortress, now of such historic interest, was being built. Thereafter, coal was mined more or less continuously, and although, for many years, in a very haphazard way, there was, on the whole, a steady growth towards a better regulation of the industry, culminating in the year 1825 with the arrival of the General Mining Association in Nova Scotia. This Company, more generally known as the G.M.A., had acquired extensive tracts in Brazil and Colombia and had also purchased the mining rights for the whole of Nova Scotia-excepting such areas as had been previously leased-the attraction being the rich veins of copper currently reported as occurring in the Province. These fabulous copper veins, upon examination, failed to materialize, but the engineer sent out to report on them returned with such good accounts of the coalfields he had seen that steps were taken immediately to investigate them. From that rime onward, the history of coal mining in Nova Scotia is one of progress and achievement. One of the first acts of the G.M.A. was to acquire the areas already leased to other concerns and develop these in a masterly fashion, employing the best machinery and talent available at that time. Such dominant control over the minerals of the Province, although it led to orderly development in the several coalfields, also, later on, resulted in restricting operations in the various coal centres to such an extent that a determined effort was put forward by the people of Nova Scotia to end such a state of affairs. Consequently, in 1857, the original lease of the G.M.A. was abrogated, the Company, however, being allowed to retain certain areas in the districts it had already developed. This opened the way for the formation of other coal-mining companies, and numbers of these immediately sprang into existence in the various coal-mining centres. In 1893, the Dominion Coal Company, Limited, was formed by the amalgamation of seven companies operating in the neighbourhood of Glace Bay, in Cape Breton. Later, in 1910, the Dominion Iron & Steel Company, Limited, obtained control of the Cumberland Railway & Coal Company, which had been formed in 1884 to acquire the rights of the two companies working in the Cumberland County coalfield.

Jan 1, 1936

The problem of thin and very thin coal seam extraction in a long perspective of Ukraine?s fuel and energy industry development was determined. Technical and economic benefits of coal seams selective mining technique including beneficial environmental impact were substantiated. The scientific and practical aspects of development of borehole underground coal gasification (BUCG) technology are considered. The technological scheme of underground gas generators is offered on the basis of the authors? criteria of fitness and adaptability to the mine and geological conditions. These charts foresee the preparation of gas generators from earth surface and directly from the present mine working by inclined horizontal boreholes. Basic research is directed at abandoned supplies extraction in coal mines. Concepts of technological decisions and technical implementation of the underground part of the gasification system are worked out with analytical models, with subsequent test verification on special options and a mine experimental gas generator. Forming the technological scheme of gasification is founded on the basis of tying up spatial and sentinel factosr of coal seam gasification taking into account sufficient impermeability of the system a «gas generator ? rock massif» and to dirigibility by thermochemical processes that flow in a rock massif. The offered solutions contain the possibility of creation of the power and chemical enterprises of gasification, taking into account the complex use of BUCG products in the ecologically reserved technological cycle. Gas generator efficiency is evaluated from an economic standpoint.

Aug 1, 2013

By K. Soldenhoff, D. Wilkins, E. Ho

In the processing of rare earth ores, a pure, mixed rare earth chloride solution is usually produced and used as the feed to solvent extraction circuits to separate the individual rare earths. Cerium(III) may be separated from the other rare earths by oxidising it to cerium(IV), which precipitates as cerium(IV) hydroxide in chloride liquors. This oxidation step may be inserted either before rare earth separation by solvent extraction or between solvent extraction circuits. Although oxidation of cerium by sodium hypochlorite has been known for many years, detailed conditions for oxidation are not readily available. The effect of hypochlorite addition, temperature, pH and cerium concentration on oxidation of cerium(III) from synthetic solutions was investigated

Jan 1, 2014

By D. A. Wheeler, Rémi Tremblay

"INTRODUCTIONDuring the last few years, through Column Flotation Company of Canada ltd, the Centre de Recherches minérales has worked on the column flotation of coal, phosphate, feldspar, talc, graphite, copper, lead-zinc and diamond ores. The operating companies and prospective deposits were located in Canada and in other countries. Since these projects were financed by the concerned mining companies, all results remain confidential unless we obtain permission to publish. Three companies have graciously allowed us to use their information which I will describe in this text. These are the Polkowice copper mine in Poland, the North Coast Industries ltd graphite deposit and a talc company which preferred to remain anonymous. I will also describe our 2 inch column which was used for all tests. Data is also given on how to scale-up the 2 inch column to industrial size.Figure 1 presents a schematic of a flotation column. Feed, at a controlled rate and pulp density, enters at about 1/4 of the height of the column from the top. A controlled rate of air is bubbled into the bottom of column through a fine-holed sparger. The column volume between the feed point and the top of the sparger is called the recovery zone. Tailings, at a controlled rate, always slightly greater than the feed rate, discharges from the bottom of the column. This difference in feed and tailings flowrates is called the bias. The floated mineral is carried through the recovery zone on air bubbles which rise into the cleaning zone which is that column volume between the feed point and the overflow at the top. As the bubbles rise in this zone they are washed of gangue material by wash water which enters over the top of the froth layer. The froth layer is maintained at a given depth during flotation but this depth will depend on the froth cleanliness, for quite a bit of cleaning by wash water is accomplished in this layer."

Jan 1, 1988

By L. Sun

A numerical model has been developed to study the air flow in the flow plate and gas diffusion layer assembly on the cathode side of a PEM fuel cell. The flow plate in this type of fuel cell often has serpentine channels and the porous layer is adjacent to the flow plate to diffuse the air to the catalyst layer. Flow cross-over of air through the porous diffusion layer from one part of the channel to another can occur. This flow cross¬over is a result of the pressure differences between different parts of the channel, and it causes the flow rate through the channel to vary with the distance along the channel. A numerical study of pressure distribution and flow cross-over through the gas diffusion layer (GDL) in PEMFC flow field using a serpentine channel system has therefore been undertaken to compare the cases of a single channel and two parallel channels, with the channels having a trapezoidal cross-sectional shape. The purpose of the present work was to study the effect of the flow plate geometry on the basic fluid flow through the plate. The flow here has been assumed to be three-dimensional, steady, incompressible, isothermal and single-phase. The flow through the porous diffusion layer has been described using the Darcy model. The dimensionless governing equations have been solved by using the commercial CFD solver, FIDAP. From the results obtained, it can be found that the single channel systems have greater maximum flow rate difference than the parallel channel systems under the conditions considered in the present study. Also, the size ratio R of trapezoidal cross-sectional shape has a significant effect on the flow cross-over and pressure variation in the flow field.

Jan 1, 2005

By Charles Amoah

Abosso Goldfields Limited has been optimizing the comminution circuit at the Damang Mine Operation for the treatment of 100% primary ore. The optimization process started at a base rate of 343 tph when treating primary crushed primary ore, and was increased to above 600 tph with partially crushed primary ore. Abosso Goldfields engaged Orway Mineral Consultants (OMC) to assist with the optimization process in 2009 and the two companies have been working together since, to further refine the process. Continuous improvement was achieved through crushing circuit modifications, changes in operating processes and grinding control system utilization. This paper discusses the improvements developed for the increase in milling capacity and improvements in final product size.

Jan 1, 2012

By Michel Gauthier, Jacque Trottier

"ForewordA symposium on base metal deposits was held in Bathurst, New Brunswick, from June 10-13, 1990, sponsored jointly by the Geological Surveys Branch of the New Brunswick Department of Natural Resources and Energy, the New Brunswick Prospectors and Developers Association, and the Geology Division of the Canadian Institute of Mining, Metallurgy and Petroleum. Papers prepared for the symposuim are being published as a series of articles in the CIM Bulletin. This third paper (the first was by Fyffe, et al., in Vol. 83, No. 938, the second is in this issue) in the series presents an overview of the tectonic setting and geochemistry of base metal deposits in the Eastern Townships of Quebec.ABSTRACTIt is well known that the classification system of volcanogenic massive sulphides (VMS) is based upon their metal content. This metal content, the result of hydrothermal solutions circulating within strata underlying the deposits, is generally thought to be related directly to two parameters: (1) the nature of the underlying stratigraphic sequence; and (2) the physico-chemical conditions that existed at the time of the hydrothermal event. Furthermore, these two parameters are, in turn, related to the tectonic setting. One must bear in mind that these parameters are diachronous and evolve with time. These factors are considered in our analysis of the major VMS deposits of the southeastern Quebec Appalachians. This analysis will describe the time and environment of formation of these deposits and integrate them into an evolving paleotectonic model.VMS deposits in the southeastern Quebec Appalachians formed during three distinct metallogenic episodes. During the first episode, which involved early closing of the Iapetus Ocean and associated destruction of oceanic crust by subduction processes(Early Ordovician?), cupriferous VMS deposits hosted by pillowed, mafic (boninitic) lava flows were formed in immature island-arc systems (""Cyprus-type"", e.g. Huntingdon deposit).In the second episode, which also occurred during the closure of Iapetus but at a later stage (Early to Middle Ordovician), mature island-arcs formed and hosted polymetallic VMS deposits (""Kuroko-type"", e.g. Eustis deposit).Finally, during culmination of the Taconic and/or Acadian orogenies (Middle Ordovician and/or Devonian), transtensional basins, associated with tholeitic to transitional mafic volcanism began to develop. Major sedimentation occurred contemporaneous with volcanism, and within this framework polymetallic VMS deposits were formed (""Besshi-type"", e.g. the Memphremagog deposit).Although incomplete, the proposed paleotectonic model represents the sequence of the tectonic settings that prevailed during the formation of the VMS deposits of the southeastern Quebec Appalachians."

Jan 1, 1991

By R. T. Erskine

"The No. 6 orebody is located 6 miles from the main op.eration of Brunswick Mining and Smelting Corporation Limited and includes open-pit and primary gyratory crushing facilities. Ore is transferred by truck to the secondary crushing facility at the main plant. About 3,500 tons of ore per day are crushed to minus % in. and ground to 68 per cent minus 400 mesh in rod and ball mills for flotation feed. Conditioning and aeration precede rougher flotation, and four stages of cleaning bring concentrates to a grade of 42 per cent Pb + Zn + Cu. Middling products are reground and refloated in a secondary flotation circuit, producing a cleaner feed and a final tails product. Primary bulk concentrate is treated with sulphur dioxide and steam-heated to l 70°F and the majority of the gangue is floated off, leaving a product that assays 57 per cent combined Pb + Zn + Cu and is suitable for marketing. This material is thickened, filtered, dried and loaded into railway cars for shipment to the smelter. Reagent use on flotation is conventional, with many compromises in dosage required to maintain the recovery of lead and zinc in the most advantageous proportions. Many refinements in the flowsheet have been made since start-up in 1966, and more may be made as laboratory and plant testwork indicate possible improvements."

Jan 1, 1971

By C. R. Julian

MECHANIZATION During the last fifteen years, numerous attempts have been made to mechanize the operations of loading ore and placing till. It is to be regretted that, to date, little progress has been made in this direction. The comparative efficiency of manual labour in Spain is the factor largely responsible for the failure to cheapen costs by mechanization. The necessity for careful classification of the ore and the need for keeping all openings small also makes the problem one of difficulty. It may be of interest to describe the various attempts at mechanization that have so far been made. CONVEYORS: (1) When stoping by layout III in San Dionisio, a trial was made of transporting the filling by jigging conveyors. This method proved un-economical, as the wall building and spreading of the till could not keep pace with the delivery, with the result that the machinery was idle a great part of the shift. (2) The transport of ore from the working places to the ore-passes by jigging conveyors and belts was also tried. Although more successful than in the case of the fill, the method could not compete with that of hand tramming, principally due to the high cost of (a) maintenance caused by the abrasiveness of pyrites, and (b) labour constantly employed on re-aligning the conveyors owing to the constant settlement of the floor. In a few cases, where a sill floor was being blocked out in virgin ground, the method showed a saving. SCRAPERS: Frequent attempts at loading by scrapers have been made, but again the only success obtained has been in the blocking-out of sill floors. The principal obstacle to the successful application of scraping, other than on the sill floor, has been that the openings, which have to be small, call for a light scraper outfit, whereas, in practice, a heavy scraper and at least a 25 h.p. winch are necessary for handling satisfactorily the ore, which is heavy and which breaks somewhat blockily.

Jan 1, 1940