Mining of Frozen Iron Ore in Northern Québec and Labrador
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Document generated on 09/29/2021 8:03 a.m. Géographie physique et Quaternaire Mining of frozen iron ore in northern Québec and Labrador L’extraction du minerai de fer gelé au Nouveau-Québec et au Labrador Förderung von gefrorenem Eisenerz im nördlichen Québec und Labrador Om P. Garg Le pergélisol au Québec — Labrador Article abstract Volume 33, Number 3-4, 1979 Mining exploration and production activities in the permafrost regions of Canada have increased rapidly over the last twenty years. This paper deals URI: https://id.erudit.org/iderudit/1000371ar with the effects of permafrost on mining iron ore in the Schefferville area of DOI: https://doi.org/10.7202/1000371ar Northern Québec and Labrador. Problems associated with drilling and blasting, digging and crushing, transportation and handling of frozen ore are See table of contents briefly outlined. The three dimensional delineation of frozen ground is achieved by a combination of ground temperature measurements and geophysical techniques. Finally some of the studies that are planned to be undertaken in the Schefferville area are briefly mentioned. Publisher(s) Les Presses de l’Université de Montréal ISSN 0705-7199 (print) 1492-143X (digital) Explore this journal Cite this article Garg, O. P. (1979). Mining of frozen iron ore in northern Québec and Labrador. Géographie physique et Quaternaire, 33(3-4), 369–376. https://doi.org/10.7202/1000371ar Tous droits réservés © Les Presses de l’Université de Montréal, 1979 This document is protected by copyright law. Use of the services of Érudit (including reproduction) is subject to its terms and conditions, which can be viewed online. https://apropos.erudit.org/en/users/policy-on-use/ This article is disseminated and preserved by Érudit. Érudit is a non-profit inter-university consortium of the Université de Montréal, Université Laval, and the Université du Québec à Montréal. Its mission is to promote and disseminate research. https://www.erudit.org/en/ Géogr. phys. Quaf., 1979, vol. XXXIII, nos3.4 , p. 369-376. MINING OF FROZEN IRON ORE IN NORTHERN QUÉBEC AND LABRADOR Om. P. GARG, Iron Ore Company of Canada, P.O. Box 1004, Schefferville, Québec GOG 2T0. ABSTRACT Mining exploration and RÉSUMÉ L'extraction du minerai de fer ZUSAMMENFASSUNG Fôrderung von production activities in the permafrost gelé au Nouveau-Québec et au Labrador. gefrorenem Eisenerz im nôrdlichen Qué regions of Canada have increased rapid Depuis vingt ans, les activités reliées à bec und Labrador. Bergwerkerforschun- ly over the last twenty years. This paper l'exploration et à l'exploitation minières gen und Produktionstàtigkeit in den deals with the effects of permafrost on ont connu un essor important dans les Dauerfrost Regionen von Kanada haben mining iron ore in the Schefferville area régions occupées par le pergélisol. in den letzten zwanzig Jahren schnell of Northern Québec and Labrador. Le présent article traite des effets du per zugenommen. Diese Studienarbeit be- Problems associated with drilling and gélisol sur l'extraction du minerai de fer handelt die Einflusse des Dauerfrostes blasting, digging and crushing, trans dans la région de Schefferville. On y auf die Eisenerz-fôrderung in der Schef portation and handling of frozen ore are discute des problèmes engendrés par le ferville Gegend im nôrdlichen Québec briefly outlined. The three dimensional forage, le minage, l'excavation, le broya und Labrador. Problème im Zusammen- delineation of frozen ground is achieved ge, le transport et le maniement du mi hang mit dem Bohren,Sprengen ,Graben , by a combination of ground temperature nerai de fer gelé. On nous explique que und Zermahlen, Transport und Behand- measurements and geophysical tech l'on peut parvenir à une délimitation tri lung von gefrorenem Eisenerz werden niques. Finally some of the studies that dimensionnelle du pergélisol en effec kurz beschrieben. Die drei-dimensionnel- are planned to be undertaken in the tuant des mesures de température et en le Delineation des gefrorenen Bodens Schefferville area are briefly mentioned. appliquant des techniques de géophy wird durch eine Verbindung von Boden- sique. On parle, enfin, d'un certain nom temperaturmessungen und geophys- bre d'études que l'on projette d'entre ischen Techniken erreicht. Zum Schluss prendre dans la région. werden einige der zukùnftigen, geplanten Arbeiten in der Schefferville Gegend kurz erwàhnt. 370 O.P. GARG INTRODUCTION Mining exploration and production activities in the permafrost regions of Canada have increased rapidly over the last twenty years. A brief history of these min ing developments in the Canadian arctic and sub arctic regions has recently been compiled by BROWN (1970) and DUBNIE (1972). Permafrost studies in the Northern Québec and Labrador Region have, until recently, mainly been undertaken in connection with the open pit iron ore mining operations of the Iron Ore Company of Canada (I.O.C.C.) (IVES, 1962; ANNER STEN, 1964: THOM, 1970). These mining operations are situated in the Labrador Trough between Gagnon and Schefferville (Fig. 1). The present paper will deal with the effects of permafrost on the Schefferville opera tions which are located within the discontinuous perma frost zone (Fig. 2). Permafrost studies in the Schefferville area began in 1955 with a joint I.O.C.C. and National Research FIGURE 1. Localisation de la région minière de Schefferville. Council of Canada program in the Ferriman Mine area (BONNLANDER and MAJOR MAROTHY, 1957; IVES, 1962; ANNERSTEN, 1964). In 1967, the focus of interest was transferred to the Timmins area, located approxi The second major problem in drilling frozen ore mately 21 km west-northwest of Schefferville, when and waste material is caused by the filling of blast the decision was made to open the Timmins 1 Mine. holes with water from the nearby talik zones. Because An experimental site was established on the Timmins of this flow of water in holes further problems are 4 deposit to study the factors affecting permafrost and encountered in terms of melting and caving of holes. to develop techniques for delineation of permafrost Therefore in practice often several holes have to be (THOM, 1970). Since 1970 the Geotechnical Engineer drilled before one is suitable for loading with explo ing Section of I.O.C.C. has developed a program of sives. The overall result is a considerable increase in routine permafrost delineation in the operating pits as drilling cost while mining frozen ore. well as determination of the physical properties of Ice present in the perennially frozen rocks absorbs frozen rocks (GARG and STACEY, 1972). Permafrost a large proportion of the energy generated by the ex is present in three of the seven open pit mines operat plosives in a blast. Therefore, in order to obtain the ing in the Schefferville area during 1978. required fragmentation, more expensive explosives are needed to break the frozen material compared with the unfrozen material. It has been found that the efficien cy of a blast is controlled not only by the total ice content, but also by the type and distribution of the PROBLEMS ASSOCIATED WITH THE MINING ice. OF FROZEN MATERIAL In the Schefferville area the two main types of ground The main problems associated with the mining of ice encountered are: a) Segregated ice in the form of frozen ore, bedrock waste and overburden in the Schef ice lenses and veins situated along the joint and bed ferville region are encountered in: 1) drilling and blast ding planes of rocks, b) Non-segregated ice occupying ing; 2) digging and crushing; 3) transportation; 4) ma the pore spaces within the rock mass. terial handling; 5) construction. In terms of blasting, both types of ice cause prob lems in achieving the desired degree of fragmentation. DRILLING AND BLASTING The remedial steps taken to improve fragmentation During rotary blast hole drilling in frozen ground, are: 1) Holes are drilled on a closer pattern and more considerable heat is generated. This is particularly the powerful explosives are required [metallized slurry case in rocks with high ice contents and when the such as Hydromex M-210 and T-3, as opposed to AN- ground temperature is close to 0°C. Due to this heat FO (LANG, 1965]. 2) Additional shallow holes are drilled generation, ice along the sides of the drill hole melts to break the near surface material, frozen due to often causing severe hole caving problems. seasonal frost. MINING OF FROZEN IRON ORE 371 LABRADOR SEA 100 0 100 200 POSTE• _i I I I KILOMETRES LHOPEDALE GULF OF ST. LAWRENCE PREDICTED OCCURRENCE OF CONTEMPORARY PERMAFROST * i FORMED AND MAINTAINED UNDER PRESENT CLIMATIC REGIME PERMAFROST ISLANDS IN PEATLANDS; AND PREDICTED OCCURRENCE OF RELIC PERMAFROST PATCHES FORMED UNDER PREVIOUS CLIMATIC REGIME SOUTHERN LIMIT OF PERMAFROST MEAN ANNUAL AIR ISOTHERM,°C FIGURE 2. Permafrost distribution in Nouveau-Québec and La répartition du pergélisol au Nouveau-Québec et au Labra- Labrador (after BROWN, 1967, 1978; IVES, 1962). dor (d'après BROWN, 1967, 1978; IVES, 1962). DIGGING AND CRUSHING TRANSPORTATION Poor fragmentation due to permafrost produces large Two problems are usually encountered during the blocks of material and an uneven pit floor resulting in transportation of frozen ore from the producing mines reduced productivity. Based on particle size analyses, in Schefferville to Sept-îles, Québec, 575 km to the it is concluded that the percentage of the particles south. These are: 1) Thawing of ore en route to Sept- larger than 3.8 cm at the secondary crusher is at least îles due to warmer weather which results in "sticky" three times more in frozen ore than in unfrozen ore. ore, difficult to remove from the rail car. 2) Freezing This is due to the increased hardness and plasticity of of the ore to the sides and bottoms of cars at the the frozen material.