Quarrying Opencast and Alluvial Mining PDF
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QUARRYING, OPENCAST AND ALLUVIAL MINING QUARRYING OPENCAST ALLUVIAL AND MINING JOHN SINCLAIR M.Eng., Ph.D., C.Eng., M.I.Min.E., Barrister-at-Law Professor of Mining Engineering and Quarrying University College, Cardiff ELSEVIER PUBLISHING COMPANY LTD AMSTERDAM - LONDON - NEW YORK 1969 ELSEVIER PUBLISHING COMPANY LIMITED BARKING, ESSEX, ENGLAND ELSEVIER PUBLISHING COMPANY 335 JAN VAN GALENSTRAAT, P.O. BOX 211, AMSTERDAM, THE NETHERLANDS AMERICAN ELSEVIER PUBLISHING COMPANY INC. 52 VANDERBILT AVENUE, NEW YORK N.Y. 10017 ISBN 978-94-011-7613-2 ISBN 978-94-011-7611-8 (eBook) DOI 10.1007/978-94-011-7611-8 © COPYRIGHT 1969 ELSEVIER PUBLISHING COMPANY LIMITED SOFTCOVER REPRINT OF THE HARDCOVER 1ST EDITION 1 969 444-20040-1 LIBRARY OF CONGRESS CATALOG CARD NUMBER 77-80489 WITH 93 ILLUSTRATIONS AND 11 TABLES All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher, Elsevier Publishing Company Limited, Ripple Road, Barking, Essex, England. CONTENTS Preface VII 1 Introd uction 2 Prospecting 15 3 Planning and Development 40 4 Removal of Overburden 61 5 The Use of Explosives in Surface Mining 105 6 Quarrying Hard Rocks 152 7 Working Iron and Copper Deposits by Open Pits. 182 8 Opencast Coal . 205 9 Surface Mining of Bauxite, Clays, Chalk and Phosphates 235 10 Surface Mining of Gold, Platinum, Uranium and Gemstones. 255 II Sand and Gravel 275 12 Alluvial Mining 289 13 Power Supply in the Surface Mining Industries 303 14 Reclamation after Surface Mining 318 15 The Management of Surface Mines 328 Appendix I-Electromagnetic Prospecting. 354 Appendix lJ-Performance of Medium and Large Draglines. 359 Appendix lII-Aggregates in Concrete 365 Index 371 v PREFACE Quarrying and all other branches of surface mining rather than diminishing in importance have become of more and more consequence economically, industrially and particularly with the depletion of high-grade deep-mined mineral reserves. Low-grade minerals require low cost extraction and this in many cases necessitates very expensive mechanized equipment with the cost of individual units running into millions of pounds in the case of large scale operations with high productivity. There has been, and there still is, a tendency for the smaller single quarries to be amalgamated into groups with large financial resources and therefore with the ability to purchase these expensive machines so necessary to make operations viable. This in turn requires wider administrative and technical knowledge in executives of these groups and as these often handle a wide range of products from widely differing systems of working, this technical knowledge should embrace the exploitation of many different types of deposits. There is, at present, a great dearth throughout the world of such qualified executives as is apparent from advertisements of vacancies in the technical press. It would appear that these industries offer an attractive career to the widely qualified and experienced technologist in these fields. This book deals with methods of working in the surface extractive indus tries, quarry management and power supply-but does not deal with related ancillary processes except where these affect quarrying operations. It should fulfil the needs of those who intend to take the Associate Membership examination of the Institute of Quarrying and degrees and diplomas in Universities and Technical Colleges. vii CHAPTER 1 INTRODUCTION The industries with which this book deals are in the process of adopting increasing mechanization and even automation. They owe no small debt to the open cast coal mining industry for it was in that industry, particu larly in the USA, that a number of mechanized methods were developed and which are now so essential for success. THE DEVELOPMENT OF MECHANIZATION In America, coal was first won by the Indians many centuries ago from the eroded outcrops of coal seams and records exist of such primitive working in 1680. Later, wheelbarrows, carts and wagons were used to haul a way the dirt from over the seam and so uncover it. Where this overburden increased in thickness, horse and mule drawn ploughs were used and later scrapers, as at Grape Creek at Danville, Illinois, in 1866 and in 1875 a similar pit was opened at Hungry Hollow nearby. In the Pennsylvania anthracite field primitive stripping using wheelbarrows for transport began in 1820. The first mechanical excavator was a British invention when in 1796 a 4 hp James Watt steam engine was installed in a scow or lighter to operate dredging equipment, and in 1805 Oliver Evans produced a similar dredge in the USA. The construction of canals and railways early in the nineteenth century created a heavy demand for mechanical aids and in 1835 a power shovel was invented by an American, William S. Otis. This was patented in 1839 and was standard in the construction and extraction industries until 1890 and, with major modification, continued to be manufactured until the 1930s. Bituminous coal stripping by Hodges and Armil using an Otis steam power shovel at Pittsburgh, Kansas, was attempted in 1877 but unfortu nately the 8 to 12 ft thickness of overburden was too much for the machine and the attempt had to be abandoned, but in 1881 Pardee and Conner 2 Quarrying, Opencast and Alluvial Mining successfully applied a steam shovel to the stripping of anthracite at Hollywood Collieries, Hazelton, Pennsylvania. In 1885 a second steam shovel was applied successfully by Wright and Wallace to the stripping of bituminous coal at Mission-field, Danville, IlIinois. It consisted of a steam dredge to which wheels were applied and with a 50 ft boom it successfully removed 35 ft of overburden to uncover a 6 ft seam, 400 yd 3 being dealt with in a lO-hour shift. In 1890 the Butler brothers employed draglines in the same area using :/:-, i and 1 yd 3 self-propelled machines with 80 ft booms which did not swing. The bucket was pulled across the surface of the overburden until it was filled when it was run out to the end of the boom and dumped. Later a 2 yd 3 dragline with a 125 ft boom was added. In 1911 Holmes and Hartshorn designed a steam-driven self-propelled completely revolving shovel with a Jt yd 3 capacity bucket and persuaded the Marion Co. to manufacture it as their Model 250 shovel. It handled 20 to 30 ft thickness of gravel and shale to uncover a 7 ft seam also at Mission-field. Its success inspired the Bucyrus Co. to put forward two fully revolving machines, one with a 60 ft boom and a 2t yd 3 dipper and the other with a 75 ft boom and a 3t yd 3 dipper. Both were steam driven, had three-point suspension, were provided with screw jacks for frame levelling and ran on rail wheels. Electrically driven shovels were introduced in 1915 when a Marion Model 271 with a 5 yd 3 dipper on a 90 ft boom was installed at Piney Fork Coal Co. in Ohio to be followed in 1916 by the Bucyrus Model 2258 with an 80 ft boom and a 6 yd 3 dipper.lt had alternative steam or electric drive. Both these manufacturers adopted an improved control on the Ward Leonard principle in 1919 and they were successful so that most subsequent models adopted this system of control. Crawler mounting replaced rail track mounting in 1925 and improved manouvrability. In this period tandem stripping was adopted in Illinois. Liquid oxygen was used to break overburden and the truck replaced rail transport, in cluding semi-trailer units. Shovels increased in capacity in the 1930s to 32 yd 3, alloy steels and aluminium were used in dipper construction and design improved with independent propUlsion tubular dipper members, two-piece booms of welded construction and more even weight distribution. Draglines were also improved and took their place as primary excavators rather than as auxiliary plant; the first large walking dragline working in anthracite at Seranton, Pennsylvania, in 1931. The first 'knee-action' shovel was brought out by Marion with a 35 yd 3 dipper in 1935 at Boonville, Indiana. In 1956 the era of the super-shovel was ushered in with the 60 yd 3 Marion Model 5760 of the Hanna Coal Co. at Cadiz, Ohio, with a 150 ft lattice type boom and a 'knee-action' crowd to reach to a height of 110 ft. A shovel three times as heavy was brought out by Bucyrus-Erie, Model Introduction 3 3850B, with a 115 yd 3 dipper on a 210ft boom. Giant draglines followed the same trend. In 1966 Marion brought out a 270 tons per minute shovel, Model 6360 known as the Captain (Figs. I and 2), with a dipper capacity of 180 yd 3 with a 215 ft boom for the Southwestern Illinois Coal Corporation's Captain Mine at Percy, Illinois, to strip two coal seams. Four motor Fig. I. Marion type 6360 shovel with 180 yd.l dipper and 215 It boom. generators convert the 14,000 volt ac power to dc to supply the twenty main drive motors capable of an output of 30,000 hp (Fig. 2). The shovel t can propel itself at mph on four pairs of crawlers each 45 ft long and 16 ft high, each shoe is 10ft across and weighs J} tons. In 1966 Bucyrus-Erie received an order to build a walking dragline Model 4250 with a 220 yd 3 bucket for the Ohio Power Co. for use in open cast coal. The cost of the machine was 20 million dollars. It develops 48,500 hp and weighs 30 million Ib (13,348 tons). 4 Quarrying, Opencast and Alluvial Mining Wheel excavators are of three types. The Kolbe was used in 1944 at the Cuba Mine in Illinois to dig a 20 ft upper layer of overburden. ]t can move 2 million yd 3 of material per month. Fig. 2. Layout 0/ Marion type 6360 shovel 30,000 hp power deck. In the brown coal lignite deposits of West Germany in the Lower Rhine district bucket chain dredges were used in the soft overburden and rela tively soft coal. The dredges were mounted on rails or caterpillars and Introduction 5 weigh up to 1400 tons. They can cut to a depth of 40 m. The buckets have capacities up to 2·24 m3 and outputs of 50,000 m3 per day have been attained. Fig. 3. Bucket wheel excavator type AR 220 in sulphur deposit. 3 .21.050 .... --.10.000-----: ~~=,==,=~=--I,~ _'1_.~. -. - , , 1, iI ! : I~SI ! : J.,50500";" $'50()+1 , ~ __________ 23 -·4 20---__ -------......:... --------------------44'300--- ------------------..... Fig. 4. The RO 400 multi-bucket chain excavator (Walter). In the bucket wheel dredge or excavator (Fig. 3) the buckets do the digging only, the material being transported by a series of belt conveyors and the digging action is superior to that of a bucket and chain dredge (Fig. 4). The bucket wheel carries from 6 to 12 buckets. Crowd action is provided on some bucket wheel excavators. The usual working height is 50 m and the cutting depth 25 m. A typical cell-less
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