Search Documents

By C. H. Bertoni

"The Superior Province of the Canadian Shield is the largest gold producing area within Archean greenstone rocks in the world, with total production of over 140 million ounces of gold. One hundred and fifty-five mines have individually produced more than 8,000 ounces, although only a relatively limited number of deposits (33) produced more than one million ounces of gold. The output from these 33 deposits accounts, however, for 85% of total gold production. The majority of grades (68%) ranges between 0.10 and 0.30 ounce per ton, and there is no linear relationship between grade and tonnage.Development of new gold mines reflects the history of gold prices. However, the response to the latest increase in gold prices was not as marked. It is concluded that gold deposits are becoming increasingly more difficult to find and new exploration techniques are urgently required.IntroductionWith most of its production coming out of the Superior Province, the Canadian Shield is the largest producer of gold from Archean greenstone rock s in the world. In total gold production, the Superior Province is surpassed only by the paleo-placers of Witwatersrand and the placers of the USSR (Anhaeusser, 1976). There has been no attempt so far to compile the historical production of the Province as a whole in a single document. The aim of this work is to fill this gap, not only for the convenience of having a complete list of gold producers, but, more importantly, as a basis on which to study the tonnage and grade characteristics of these deposits."

Jan 1, 1983

The Challenges in Mining _Large expensive assets that are not being utilised as well as they should _?Silo? operations plan, schedule and execute in isolation?poor visibility across the Value Chain _Disruptions or unforeseen events have serious upstream and downstream impacts _Exacerbated by multiple information systems, mostly spreadsheets _Strategic simulation (supply and demand) is often poorly Handled

Nov 1, 2011

By Jürgen Kretschmann

The Islamic Republic of Iran is a very important producer of raw materials in the world. The country holds 68 types of minerals, including salt, sand and gravel, chrome, lead, zinc, copper, coal, gold, and iron-ore. With more than 37 billion tons of measured and indicated reserves and 55 billion tons of total mineral resources, Iran is ranked among the 15 major mineral-rich countries. Sangan iron-ore mines (SIOM) is one of the biggest iron ore mining complexes in Iran, located in a remote, but strategically important area near the Afghanistan border. The Iranian government has planned several mining projects in this region for a stepwise development over the next 5 years to satisfy the growing demand of the Iranian steel industry. In cooperation with private companies, these projects shall be realized as sustainable as possible. This paper introduces SIOM and describes socially responsible activities undertaken during the initial development of this mining complex. The effects of these activities will be demonstrated. Unique attributes of the Sangan area have a significant impact on the acceptance of SIOM by regional stakeholders. The government has made several social investments that benefit workers´ families and the community. They are attempts to build social capital for the mining operations and demonstrate a commitment for socially responsible mining to the communities and the local population. They aim to create a balance between the local and regional expectations and requirements and the necessity to secure the corporate profitability at a reasonable and sustainable level. Investment in socially responsible activities is not a choice but a necessity to improve the relations between mining companies and stakeholders in the communities. It is recommended that social investments should be carefully planned and implemented from the early stages of mining activities, and should proceed throughout the life cycle of the mines.

Aug 1, 2013

By C. Blawert

In previous studies of various HPDC magnesium alloys we found that the corrosion properties of the skin are inferior in comparison to the bulk, However, this is surprising as one would expect better corrosion properties for the finer microstructure of the skin, In a more detailed study using 2 and 6 mm thick sections from HPDC AZ91 step plates, the corrosion results of the original skin, the slightly removed skin and the bulk were compared, Indeed, the corrosion measurements including potentiodynamic polarization, long term polarization resistance measurements and electrochemical impedance spectroscopy (EIS) revealed a lower corrosion resistance of the original as-cast skin. An explanation for this corrosion behavior was found, on the one hand, in the microstructure concerning especially the amount and distribution of the 13-phase and, on the other hand, in the composition, including the distribution of the most important alloying element Al and of some impurities such as Fe.

Jan 1, 2005

By G. Whittle, R. Peevers, P. Moryoussef

Enterprise optimization is a relatively new optimization approach to mine planning used to jointly consider all aspects of a mining operation affecting the mine planning process and related valuation. In this paper, it is applied at SEMAFO's Mana operations in Burkina Faso, consisting of several open pits and a proposed underground mine. The surface-minable ore is relatively shallow, and the pits are long and linear. The underground operations, as currently envisioned, will consist of a stoping operation accessed by two ramps from the surface. Power is a concern at this property due to local power being produced largely by diesel generators, and it has become one of the key optimization constraints. Other important parameters are the mining and processing rates, underground configuration and cutover elevation. Enterprise optimization was found to improve net present value for the Mana Operations property by simultaneously optimizing multiple parameters and constraints to arrive at an optimal pit and mining phase design, optimal cut-off grades over time, and optimal ore feed based on ore hardness, power constraints, and head wades. Reserves were expanded several times over the course of the study to improve the valuation of the mining operation and put SEMAFO in its present enviable position of ongoing reserve increases.

Jan 1, 2011

1.Assessment of methane content in coal. Given a naturally low methane content in 11 Coal Seam and the fact that the areas of the 11 Seam adjacent to the tunnelway were degassing for a very, very long time due to previous development and mining, it is conservatively estimated that the remaining in -situ methane is less than 0.5m3/tonne. 2. Continuous miner cutting rate based on the past practice. The best loading rate recorded at the past operations of Smoky River Coal was 45 seconds for a 8 tonnes shuttle car. Using these records, the maximum peak loading rate potential at the face is calculated at 0.178 tonnes per one second or 10.67 tonnes per one minute. 3. Methane release at the face. ?The actual face methane liberation, conservatively assumed at 40% of the total in situ content: 0.20 m3/tonne ?The peak cutting rate: 0.178 t/sec ?The maximum (peak) face methane release: 0.20*0.178 = 0.036 m3/sec

May 1, 2003

By Maureen McGuiness

"The pastefill circuit at the Bell Allard Mine in Matagami, Quebec started up in August 1999. The surface pastefill plant produces a cemented paste which is sent underground by gravity through a vertical pipeline in the mine ventilation shaft. Difficulties with paste flow during the start-up highlighted the importance of understanding paste rheology and the effect of operating procedures on line wear. By June 2000, the original circuit had been modified to include a paste pump to transport the paste to the shaft.The steps taken during the paste plant commissioning are discussed. The final flow sheet is presented, focussing on the use of instrumentation to ensure full column flow and proper distribution underground. Resistance modelling and accelerated curing of samples are examined as possible ways of predicting paste resistance to ensure compliance with the mine’s paste specifications.INTRODUCTIONCommissioning a new plant can be difficult and time consuming. The start-up of Noranda’s Bell Allard paste backfill plant was no exception. Since the first day it went into operation, the paste circuit could not meet the tonnage and paste quality requirements of the mine because the paste would not flow by gravity into the vertical pipeline in the mine’s ventilation shaft.Diagnosis of the pastefill problems proved difficult. It was only when the rheology of the Bell Allard paste was understood that the flow problems were solved. To ensure that the paste placed in the stopes meets mine requirements, two methods of paste resistance prediction are being developed."

Jan 1, 2002

By Pizhi Zhao, Jingwei Zhao, Zhenshan Liu, Yiheng Cao

"A new Al-Mg-Si-Zn alloy designed for automotive outer panel was trial-produced with industrial procedure. The final product shows a strong planar anisotropy. X ray diffraction analysis shows such strong anisotropy is caused by the dominating cube texture component in the final product. The reason for such high cube texture component was investigated by tracing texture evolution starting from the hot roll slab. It is found that certain cube texture components already exists in the hot rolled slab. The density of cube texture component shows as a wavy change through the following1st cold rolling, inter-annealing, 2ndcold rolling and solution treatment. This study shows that the cold rolling in the laboratory can well represent the texture evolution during the industrial production. The results obtained by lab rolling hints that change of second cold rolling reduction has weak effect on the planar anisotropy, when the gauge of hot rolled slab and final sheet are fixed.INTRODUCTIONWith the rapid progress of light-weighting in the automotive industry, aluminum sheets get more and more application as closure panel and structure parts. Recently the dominating alloy for outer panel is 6xxx series, containing the main alloy elements Mg and Si. The popular gradesareAA6016,AA6111, AA6022, and AA6014. These alloys still cannot satisfy the various requirements from automotive manufacturers. Most suppliers of automotive aluminum sheets are developing their own specific grades according to the customer’s demand. To increase the baking response, anew Al-Mg-Si-Zn alloy was designed, concerning the high combination energy between Zn solutes and vacancies formed during the quenching stage of automotive sheet manufacture. This combination is helpful to the precipitation of ß”phase during the paint baking (Wang, 2015,2016; Yan, 2014).The plastic strain ratio (r value)is a key index of the formability of automotive body sheet. A high r value means a good formability. The r values in different directions can be used to evaluate the planar anisotropy of the metal sheets. The trial produced Al-Mg-Si-Zn sheet shows a strong planar anisotropy with respect to r values. Since the r value is tightly related with texture, the texture evolution from hot roll slab (HRS) to final T4P temper was analyzed with X ray diffraction (XRD) to find the reason for the high anisotropy. Besides, the cold rolling reduction (CRR) was varied in the laboratory to modify the texture distribution, i.e., the planar anisotropy."

Jan 1, 2018

By K. Szczesny

This paper considers the integration of uncertain real-time logistics data for reactive construction scheduling. In order to manage a construction project efficiently, an accurate schedule representing the current project progress is inevitable. The quality and up-to-dateness of such a schedule depends on the availability of real-time data. Typically, real-time logistics data contain information about the availability of material, equipment and personnel as well as delivery dates and site conditions. The accuracy and inherent uncertainty depends on the location where the real-time data was acquired. Currently, the integration of such data into a construction schedule is a very time-consuming, manual and, thus, errorprone process. Therefore, this paper proposes a methodology that enables an automatic integration of such uncertain data into construction schedules. By integrating uncertainties into the existing schedule their impacts on the construction work can be evaluated. For this, discrete event simulation is applied. In order to model uncertain input parameters for simulation models this methodology applies the fuzzy sets theory. In combination with alpha-cut sampling technique, discrete model input parameters are obtained. By applying reactive scheduling with several discrete event simulation experiments, the results can be used to modify construction schedules according to agreed timeframes and costs. In order to demonstrate and validate the presented approach an example is conducted.

Aug 1, 2013

By T. W. Wlodek

"AbstractThe results of research into the fatigue properties of SAE 1080 carbon steel and nickel-chromium-molylbdenum steel for mining drill rods are analysed and described in detail.The effect of water corrosion on the fatigue strength of drill rods of these two steels in the as-rolled condition has ,been investigated and the beneficial influence of shot-peening on their dry and water-corrosion fatigue strengths determined by employing the method developed previously (1).Eight S-N curves for as-rolled and shot-peened mining drill rods under both dry and water corrosion conditions have been derived and their shape and relative position are discussed. The main features relating to field performance of the drill rods are analysed.Purpose of Research and Outline of ProgrammeDRILLING holes in rock and ore by means of drill rods attached to a pneumatic drill is a basic procedure required in mining operations. Detonation of explosives placed in these holes is at present the only practical method of breaking down the rock and ore.A drilling rod is supported by its bit end in the drilled rock. Its shank end, fixed in the drilling machine, transmits impact energy to the cutting edges of the bit. On the field performance of the drill rod depend a number of basic mining operations such as sinking, drifting, and stoping. The drill rod is there-fore regarded as one of the most important tools used in the mining industry."

Jan 1, 1952

By Rowena Anderson

Mining companies are now looking for more effective ways to engage the community in public participation. Consensus-based approaches are becoming the most popularly applied way of achieving meaningful public participation. This paper introduces the principles surrounding consensus-building approaches and the processes for getting them started. The Healthy Communities Movement is one such consensus-based approach that offers a well-established holistic model for conceptualizing a healthy sustainable community. It also highlights the importance of public participation as an essential component of achieving a sustainable community. The paper concludes by illustrating how current company-community relations programs can utilize these models.

May 1, 2002

By CIM Mineral Resource, Mineral Reserve Committee

The CIM Mineral Exploration Best Practice Guidelines (the Exploration Guidelines) have been prepared to assist professional geoscientists and engineers to conduct consistently high-quality work in order to maintain public confidence. The Exploration Guidelines are meant to assist professional geoscientists and exploration practitioners in planning, supervising, and executing exploration programs. In Canada, there are generally two types of public resource reporting: “Disclosure”, as defined by NI 43-101, is the reporting of technical information to the public and market participants for securities legislation purposes where a Qualified Person (QP) must be involved, and reporting of exploration information for governmental agencies to support obligations under laws including the Mining Acts of each of the Provinces and Territories. The Exploration Guidelines are also relevant where the results will not be publicly reported but are intended for internal company use. While this document is intended as guidance for work conducted or supervised by geoscientists in Canada, many of the practices described herein can be adapted to mineral exploration activities in other countries. The Exploration Guidelines are not intended to inhibit original thinking, or to prevent the application of new approaches that may develop into fundamental components of successful mineral exploration programs. Rather than provide prescriptive solutions to specific issues, they include general guidelines for current professional practice and to demonstrate and defend the merits of new methods. These guidelines do not preclude individuals and companies from developing more detailed guidelines specific to their own requirements. The initial version of the Exploration Guidelines was prepared by the Canadian Institute of Mining and Metallurgy and Petroleum (CIM) Exploration Best Practices Committee and adopted by CIM Council on August 20, 2000. On January 9, 2018, CIM Council formed a new committee, the Mineral Resources and Reserves Committee (CIM MRMR Committee) with a mandate to, among other things, update the Exploration Best Practice Guidelines. The mandate for the committee was accepted by CIM Council on March 2, 2018. The new document was adopted by the CIM Council on November 23, 2018.

Nov 23, 2018

By G. E. Norman, J. F. Jackson, A. L. Mckague

"The treatment of nickel-copper concentrate in the new smelter at Falconbridge Nickel Mines Limited, Falconbridge, Ontario, is described. The concentrate in a slurry form is partially roasted in a fluid-bed roaster and the calcine is smelted in an electric furnace. The roaster gases are treated in an acid plant. IntroductionSmelting began at Falconbridge in 1930 with the first blast furnace treating high-grade ore containing 2-3% nickel. In 1933, the Falconbridge concentrator was built and started producing a bulk sulphide concentrate containing 4% nickel. A sinter plant was built to agglomerate and partially roast this concentrate. The sinter was smelted in blast furnaces along with high. grade magnetic ore. Matte from the furnaces was treated in Pierce-Smith converters to produce shipping matte which was refined at the company's plant in Norway."

Jan 1, 1980

By Geology Staff, C. H. Stockwell

"The Flin Flon base metal mine, owned and operated by the Hudson Bay Mining and Smelting Company, is on the Manitoba-Saskatchewan interprovincial boundary at a point 400 miles north of the International boundary. The deposit was discovered in 1914 by Thomas Creighton and the Mosher and Dion brothers. Since production commenced in 1930, 25,000,000 tons of ore have been mined. On January 1st, 1946, reserves were estimated to be 26,000,000 tons, averaging 2.99 per cent copper, 4.i4 per cent zinc, and 0.089 oz. gold and 1.25 oz. silver per ton. In addition to the four metals named, others recovered from the ore include- cadmium, selenium, and tellurium. The mine workings extend to the 3,750-foot level, but little development work has yet been carried on below 3,250 feet.The known ore occurs in six lenticular to irregular bodies within a zone 500 feet wide. These bodies average 900 feet long, 70 feet wide, 1,500 feet in vertical depth, and 2,500 feet in length along the plunge. They were formed by replacement of the country rock and include ore of two types, solid sulphides and disseminated sulphides. Seventy per cent of the total known ore is of the solid sulphide type. This consists essentially of metallic sulphides- chiefly pyrite- with included remnants of the host rock, and additional quartz and carbonate. In places, the ore exhibits banding, inherited from pre-existing structures. The disseminated ore occurs usually on the footwall side, and along the bottom of the plunge, of the solid sulphide bodies."

Jan 1, 1954

En quoi consistent les études de suivi des effets sur l?environnement (ESEE)? Les ESEE constituent une méthode de suivi scientifique que l?on peut employer pour déterminer la santé des écosystèmes aquatiques (qui peuvent être touchés par l?activité humaine) et l?efficacité des mesures de protection de l?environnement. Les ESEE sont des évaluations scientifiques itératives du poisson, de l?habitat du poisson et des ressources halieutiques. Le programme comporte des phases séquentielles de deux à six ans de suivi, d?interprétation et de compte rendu au cours desquelles la fréquence et le type de suivi dépendent des résultats des études précédentes. Le programme des ESEE pour les mines de métaux est fondé sur un accord conclu à l?unanimité entre les intervenants. Les exigences du programme et les guides techniques connexes ont été élaborés à la suite d?une consultation multilatérale à laquelle ont participé les représentants du secteur privé, du gouvernement et des collectivités. Toutes les mines assujetties au Règlement sur les effluents des mines de métaux (REMM), aux termes de la Loi sur les pê ches, doivent procéder à une ESEE dans le cadre de l?autorisation qu?ils ont reç ue de rejeter des effluents. Le REMM a été enregistré le 6 juin 2002 et publié dans la Partie II de la Gazette du Canada le 19 juin 2002 (SOR/DORS/2002-222).

Nov 1, 2002

By C. G. Bruce

"ON NOVEMBER 15th, 1950, the Department of Mines and Technical Surveys announced the discovery of vermiculite near Perth, Ontario. The announcement followed nearly a month of study to determine so far as possible the potentialities of the deposit and quality of the material from surface indications. The mineral was identified by the writer in the field among samples submitted by Mr. Arthur Powers of Stanleyville or, September 22nd, 1950. Within a week of the announcement, mining rights to properties covering a major portion of the deposit had been acquired by commercial interests.Hitherto, Canada has had to import her entire requirements of vermiculite. Prospects of .a domestic supply gave promise of considerable benefit to many industries, particularly the building industry, and to the consumer public. Should the deposit •prove large enough there was also the possibility of exporting to centres in the United States.Field and laboratory studies were continued at the Mines Branch during the winter of 1950-51 as opportunity occurred. It is the purpose of this paper to describe the results of these •preliminary investigations, to attempt to present the Stanleyville occurrence in its proper perspective with regard to similar occurrences elsewhere, and to review the salient features of the vermiculite industry.Properties and UsesVermiculite is a hydrated magnesium aluminum silicate. In appearance it resembles mica, having the same micaceous cleavage, but it differs from that mineral in being very soft, pliable, and inelastic. Colours range from black through dark olive-green and brown to almost colourless."

Jan 1, 1952

By William Petruk, J. R. Schnarr

The behaviour of minerals during flotation of a fine-grained pyrite-rich base metal ore was investigated by studying the feeds. concentrate and tailings from every flotation cell in the mill of Brunswick Mining and Smelting Corp. Ltd. Bathurst. New Brunswick. The samples were analyzed for Zn, Pb, Cu. Fe, Ag. Sb, Sn, Bi, In. Hg, Mo and As. Mass balances were computed and recoveries of all metals from each cell. from each circuit and from the mill were calculated. The percentages of sphalerite. galena and chalcopyrite occurring as free grains in each product were determined with an image analyser, as were size analyses for free mineral grains and middling particles, and compared with screen analyses. The results show that the behaviour of minerals is defined much better by the recovery of free mineral grains than by the recovery of elements. The recovery of free sphalerite in the zinc circuit is 96 wt %, whereas Zn recovery from the same circuit is 88 wt %. the difference being due to unliberated sphalerite. The recovery of free sphalerite from the mill feed is 88 wt % and Zn 78 wt %. The recovery of free galenafrom the mill feed is 88 wt % and Pb 64 wt %. The recovery of free chalcopyrite is 75 wt % and Cu 45 wt %. Size analyses show that more sphalerite and chalcopyrite can be liberated by regrinding. but the galena is so fine grained that regrinding would not necessarily improve liberation. Silver occurs mainly in tetrahedrite and galena; the main loss in the tailings is due to large (+ 26 um) and small (-1 um} free and unliberated tetrahedrite grains.

Jan 1, 1981

By I. M. Gordon, J. Blackshaw

"Run-of-mine ore is reduced to 4 per cent on 4 mesh (3/ 16 inch), using four stages of dry crushing. The mill feed is then reduced to 2 per cent on 48 mesh and 60 per cent through 200 mesh, using one stage of ball milling in cyanide solution. During the subsequent treatment about one-tenth of the tonnage is removed as a table concentrate and ground to 77 per cent through 325 mesh. The size of the mill tailing is 66 per cent through 200 mesh.Four stages of ore reduction began when the dry crushing plant at No. 26 Shaft came into operation at a maximum rate of 440 tons an hour on July 31, 1941. A detailed description of the crushing plant was published in C .I .M. Trans., Vol. LVI, 1953.One-stage ball milling in cyanide solution came into full operation on January 11, 1938. The ball milling plant had a capacity of 4800 tons daily when reducing mill feed at 2. 7 per cent on 1/ 4 inch to 54. 3 per cent through 200 mesh. Primary grinding to 60 per cent through 200 mesh commenced May 22, 1945, when the feed was 3 per cent on 4 mesh. Under these conditions the capacity of the ball milling plant is estimated at 4300 tons daily. A description of the 11 Hollinger Crushing and Grinding Plant"" by D. C. McLaren was published in the Canadian Mining Journal, June 1944.The concentrate grinding circuit using a 7 x 15 low discharge ball mill and a 19-foot diameter bowl classifier with a 6-inch centrifugal pump to close the circuit began operating in the ball milling plant on October 24, 1939."

Jan 1, 1965

By A. E. Aho

"The Pacific Nickel property lies 7 miles northwest of Hope and 100 miles east of Vancouver, in the Coast Mountains of southwestern British Columbia. Nickel-copper sulphides were discovered in ultrabasic rocks on this property in 1923 and the deposits were explored by Pacific Nickel Mines until 1937, then again between 1951 and 1954 by Pacific Nickel Mines and by Newmont Mining Corporation through its subsidiary,Canadian Ore DepositsWestern Nickel. The property was studied by C. E. Cairnes (1) in 1924, by W. E. Cockfield and J. F. Walker (2) in 1933, by H. C. Horwood (3), (4) in 1936 and 1937, and by the writer in 1951 and 1952. Except for a few thousand tons for trial shipments, the property has never been mined. Indicated ore reserves now total somewhat over one million tons averaging about 1.4 per cent nickel and 0.5 per cent copper, with lesser values in precious metals and cobalt.GEOLOGIC SETTINGThe nickeliferous ultrabasic rocks form part of the core of a 15-milewide block of Late Palæozoic metamorphic rocks and Mesozoic intrusives which extend north-south between the coast batholith of British Columbia and the Chelan batholith of Washington. Margins of this block are faulted in part against less metamorphosed volcanic and sedimentary rocks largely of Jurassic and Lower Cretaceous age (Geo/. Surv., Canada, Map 737 A, 1942). Serpentinites, suggestive of deep transgressive structure, occur within the block, and also at its east margin along faults which are southern extensions of the regional Yalakom-Fraser River fault zone. Some of the other mineral deposits in the Hope area appear to be spatially related to these major faults.The mineralization at Pacific Nickel occurs almost exclusively within a stock-like mass of ultra basic rocks which mingle with, and partly cut, a larger batholithic mass of genetically related diorites and norites of late Mesozoic age (Figure 1 ). The ultra basic mass consists essentially of fresh, medium-grained hornblendic pyroxenite with peridotitic cores and with a remarkable margin of pegmatitic hornblendite. The most hornblendic rocks appear to be chiefly products of reaction and replacement of the pyroxene and olivine rocks. The mineralization consists of disseminated and massive pyrrhotite, with subordinate pentlandite and chalcopyrite, amongst fresh olivine, bronzite, and, Jess commonly, augite and hornblende. Both the ultrabasics and mineralization are cut by small hornblenditic and dioritic dykes, and by veins and alteration zones."

Jan 1, 1949

By W. Hrynewich

"The Central Canada Potash facility, a division of Noranda Metal Industries Limited, is located 3 kilometres south of the junction of Highways 16 and 2, about 75 kilometres south-east of Saskatoon, Saskatchewan. The site occupies 26~ hectares of land and includes well-equipped machine and electrical _shops, a 325,000-tonne muriate storage and reclaim warehouse, a stores warehouse, processing plant (mill), two mine shafts (one for production, the other for servicing and personnel transport), as well as a two track product loading complex. Access to the site is by road and railway (CN and CP Rail). Suppliers of operating and maintenance use both means of transportation, whereas muriate shipments are entirely by railway.Currently five continuous mining machines - one a Goodman 526 borer and four Marietta 911-A units produce some 10,500 tonnes of ore per operating day. A smaller Voest-Alpine Af.1-100 boom type miner is used for floor cutting which was previously done by a production unit. In order to maintain safe, competent ground conditions only 35 percent of the total ore is extracted. At this rate mine reserves are deemed adequate for about 100 years. The plant has operated since August 1969 and has a current practical annual capacity of 1,270,000 tonnes of muriate. As of June 30, 1981, some 11.9 million tonnes of muriate had been produced from 31.4 million tonnes of ore. Of the total muriate, 6.1 million tonnes was granular, 4.8 million was coarse, and 1.0 million was standard. No standard product has been made since August 1978."

Jan 1, 1982