Alluvial Prospecting and Mining (eBook)

Front Cover 1
Alluvial Prospecting and Mining 4
Copyright Page 5
Table of Contents 6
PREFACE TO SECOND EDITION 8
PREFACE TO FIRST EDITION 10
CHAPTER I. INTRODUCTION 12
Classification 12
Tests for minerals 13
CHAPTER II. PROSPECTING METHODS 18
Scout Prospecting 18
Preliminary systematic prospecting 19
Mode of operation drilling with casing
Type of tool used 33
Drilling without casing 34
Drilling in difficult ground 35
Withdrawal of casing 36
Supervision of drilling 38
Banka power drill 38
The Conrad pit digger 41
Withdrawal of casing 42
Rate of excavation 42
Pitting and drilling compared 43
CHAPTER III. SAMPLING AND VALUATION 44
Washing appliances 44
Cradle or rocker 45
Long torn 46
Sampling of bore holes 50
Calculation of reserves 64
CHAPTER IV. WATER SUPPLY 71
Water measurement by rectangular weirs 72
Earth dams 77
Concrete dams 78
Spillways 81
Maintenance of dam 81
Leats, ditches, or canals 81
Maintenance of leats 89
Design of pipe-lines 96
Friction head 107
CHAPTER V. SLUICING 110
Sluice boxes 110
Grade of a sluice box 112
Riffles 114
Rail riffles 115
Angle and T-iron riffles 115
Rock pavements 115
Undercurrents 115
False bottoms 116
Glean up 116
Tailings 116
Prevention of theft 117
Details of practice 118
Deposits in swamps or marshes 130
Working of terrace and eluvial deposits 130
Ground sluicing 131
Water required 132
Hushing or booming 132
Exploitation plans 138
CHAPTER VI. DRY CONCENTRATION OF MINERALS 140
The pneumatic table, or air-float separator 140
Electrostatic separation 143
Efficiency of separation 150
High intensity magnetic separators 150
CHAPTER VII. FORWARD PREPARATION OF OVERBURDEN 154
Drilling practice 155
Blasting practice 156
Type of drill used 159
Diamond drills 159
Parmanco drill 161
McCarthy auger drill 162
CHAPTER VIII. HYDRAULIC MINING 163
Giants or monitors 163
Operation of giants 164
Nozzle or pressure pumps 171
Potential energy of jets 171
Duty of giants 172
Hydraulic elevators 175
Water required 177
Maximum height of lift 178
Capacity of elevators 179
Bedrock ditches 183
CHAPTER IX. GRAVEL PUMPING 185
Method of operation 185
Sluice boxes for gravel pump mining 185
Water required 186
Grade of sluice boxes 188
Conditions for successful working 188
Records 189
Exploitation plans 189
CHAPTER X. MISCELLANEOUS METHODS OF MINING 191
Drift mining 191
Deep lead mining 193
Dragline excavators 195
Power shovels 205
Cableway draglines 206
Multi-bucket excavators 207
Tractor equipment 208
Bucket wheel or rotary excavators 213
Washing plants 214
Maintenance of equipment 219
CHAPTER XI. SELECTION OF EQUIPMENT 222
Wet methods 222
Computation of reserves for wet methods 223
Dry methods 223
CHAPTER XII. ALLUVIAL DIAMOND MINING 229
South-West Africa 234
Belgian Congo 236
Angola, Portuguese West Africa 240
CHAPTER XIII. MINING OF BEACH SANDS 243
BIBLIOGRAPHY 251
INDEX 254