A Practical Manual of Minerals, Mines and Mining ... Illustrated, etc

Front matter

A PRACTICAL MANUAL OF MINERALS, MINES, AND MINING A PRACTICAL MANUAL (IF MINERALS, MINES, AND MINING COMPRISING SUGGESTIONS AS TO THE LOCALITIES AND ASSOCIATIONS OF ALL THE USEFUL MINERALS, FULL DESCRIPTIONS OF THE MOST EFFECTIVE METHODS FOR BOTH THE QUALITATIVE AND QUANTITATIVE ANALYSES OF EACH OF THESE MINERALS, AND HINTS UPON THE VARIOUS OPERATIONS OF MINING, INCLUDING ARCHITECTURE AND CONSTRUCTION. BY Prof. H. S. OSBORN, LL.D., AUTHOR OF "THE METALLURGY OF IRON AND STEEL." ILLUSTRATED BY ONE HUNDRED AND SEVENTY-ONE ENGRAVINGS PHILADELPHIA: HENRY CAREY BAIRD & CO., INDUSTRIAL PUBLISHERS, BOOKSELLERS, AND IMPORTERS, 810 WALNUT STREET. LONDON: E. & F. N. SPON, 125 STRAND. 1888. Copyright by HENRY CAREY BAIRD & CO., 1887. Collins Pkijjting House, 707j Juyne Street.

Preface

. The object of this manual is to place before the practical mineralogist and miner all the important help which may be derived from the present state of knowledge as it bears upon the departments of useful mineralogy, mining, and mines. We have intended to make use of the best results, not only of experi ment, but of successful work, and, therefore, only the best methods have been, in most cases, presented. Nevertheless, it frequently happens that a method adopted in one condition, or under certain circumstances, must be modified under other con ditions, and there may be sound reasons for adopting another method to attain the same result. Hence, where it is difficult to pronounce upon one method, we have given an alternative. In chemical analyses and reductions, especially in the methods of detection or determination, we have confined ourselves to that method which was simplest in treatment.

In practical and most technical work much depends upon the manipulation — indeed, more depends upon the neatness and the judgment of the chemist than upon his method or the process he has adopted. This work is divided into two principal parts and one subor dinate. The first part treats of the useful minerals — their physical properties, geologic positions, local occurrence, and associations ; their methods of chemical analysis when we wish to determine their natures and richness ; their furnace or dry assay ; and their probable present commercial values and uses ; VI

PREFACE.

. together with such cautions which long experience has proved that the miner and practical mineralogist should observe in his researches. The second part describes the various methods of excavating and of timbering. It includes all brick and masonry work during driving, lining, bracing, and other operations included in general or special mining architectural work. Following, Part II. , the practical work of digging and boring artesian and other deep wells is fully described, with notices of the tools used and how to provide for the accidents and difficul ties sometimes met with in these operations. Oxford, Ohio, December 15, 1887. CONTENTS

Part I. Mining Mineralogy, And Economic Treatment And History Of The Useful

MINERALS. MINING MINERALOGY. Preliminary Principles and Preparations. PAGE Necessary requirements for the successful stud)- of mining mineralogy . 17 Crystallization, and importance of a knowledge of it . . . . 18 Hardness of minerals an important characteristic in their determination . 19 Cleavage ; Fracture ; Color ; Streak ....... 20 Specific gravity; Explanation of; Great importance of, in mineralogy; Method for determining . . . . . . . . .21 Practical uses of to miners and artisans ....... 26 The blow-pipe ; Description of, and manner of using it .... 27 Collection of materials for blow-pipe practice ...... 28 Preparatory practice ; Hints for beginners ...... 29 For practice in assaying .......... 30 Directions for removing the bead ........ 32 Magnetism ; Application of, in determining minerals ; Cupellation . . 33 Muffle ; Substitute for 34 In review ............ 35 Chemical analysis ; Elementary principles of chemistry ; The elements . 36 Combining weights of elementary bodies ; Table of atomic weights . . 38 Note, explanatory of the foregoing table . . . . . .39 The practical use of the table of atomic weights ... .39 The groups ; Grouping of compounds forming a convenient classification for the student, in their relation to the action of reagents : First.

Metallic oxides not precipitated from their solutions by sulphuretted hydrogen, hydrosulphuret of ammonia, or alkaline carbonates — the alkalies proper ............ CONTENTS. PAGE Second. Metallic oxides not precipitated from their solutions by sulphuretted hydrogen, but precipitated by hydrosulphuret of ammonia only under certain circumstances, as salts, and also precipitated by alkaline carbonates — the alkaline earths ........ 42 Third. Metallic oxides not precipitated by sulphuretted hydrogen but precipitated as oxides by hydrosulphuret of ammonia . . . .42 Fourth. Metallic oxides not precipitated from their acid solutions by sulphuretted hydrogen but completely precipitated by hydrosulphuret of ammonia as sulphurets . . . . . . . . . .42 Fifth. Metallic oxides completely precipitated from their solutions, whether acid, alkaline, or neutral, by sulphuretted hydrogen, their sulphurets being insoluble in alkaline hydrosulphurets ...... 42 Sixth.

Metallic oxides completely precipitated from their acid solutions by sulphuretted hydrogen but not from their alkaline solutions, their sulphurets being soluble in alkaline sulphurets ...... 43 Reagents; Water 43 Alcohol ; Hydrogen . . ........ 44 Chlorine ............ 45 Bromine and Iodine .......... 46 Oxygen ; Iron . . . . . . . . . . .48 Zinc ; Tin ; Hydrochloric acid ........ 49 Nitric acid ; Aqua regia ; Sulphuric acid . . . . . . 50 Hydrosulphuric acid gas ......... 51 Acetic acid ; Oxalic acid ; Succinic acid ; Tartaric acid .... 52 Sulphurous acid or anhydride ; Carbonic dioxide ; Molybdic acid ;' Potassa ............. 53 Soda; Ammonia; Lime-water; Alumina; Litharge .... 54 Oxide of copper ; Nitrate of potassium ; Sulphate of potassium ; Carbonate of potassium; Black flux ......... 55 Chlorate of potassium ; Permanganate of potassium .... 56 Sulphocyanide of potassium ; Chloride of sodium ; Sulphuret of sodium . 57 Sulphite of sodium ; Carbonate of sodium ; Borax ; Phosphate of sodium ; Acetate of sodium ; Succinate of sodium ...... 58 Nitro prusside of sodium; Chloride of ammonium; Hydrosulphide of ammonium; Molybdate of ammonium ; Acetate of ammonium ... 59 Oxalate of ammonium; Neutral succinate of ammonium ; Chloride of barium ; Nitrate of barium ; Carbonate of barium . . . . .60 Chloride of calcium ; Sulphate of Magnesium ; Nitrate of silver . . 61 Litmus paper ; Red litmus paper ; Salt of lead paper ; Microcosmic salt . 63 Cautions and suggestions ; Selecting a room for a laboratory . . .63 Sand bath ; Assay furnace ; Construction of, illustrated and described . 64 Analytical scales ; Requirement for . . . . . . .67 How to use reagents and glassware ....... 68 Caution; The use of reagents ; Heating glassware . . . . .69 CONTENTS.

IX . PAGE Heating flasks and beaker glasses ; Water 70 A list of usual chemical apparatus 71 List of chemicals ....... 70 Folding filter papers ;* Inverted cone of platinum foil in a filtering funnel . 73 Filtering apparatus, illustrated and described 75 Platinum crucibles ; Brasque 77 Fuming nitric acid and its use 7g Sodium disulphate and its use with powdered assays .... 79 ECONOMIC TREATMENT AND HISTORY OF THE USEFUL MINERALS. Treatment of the important minerals ; Comparative standard of the hardness of a mineral ........ 81 Table of comparative hardness of minerals ...... 82 GOLD.

Occurrent condition and form in nature ; Native ; Hardness and specific gravity ; Color ; Ductility and malleability ; Composition ... 83 United States localities .......... 84 Mines of South America and Mexico ....... 86 Total annual production of gold in the United States .... 87 Geology of gold and its associations ; Its combinations with sulphur . . 88 European localities where gold has been found ; Australian deposits . 89 Gold in gravels and sands of rivers ; Its occurrence in rocks ; Chemical action in gold min'es of North Carolina ...... 90 Gold deposits of North Carolina ........ 91 Native gold ; Great variety in the fineness of . . . . . .92 Alloys of gold with silver ; Assay of California gold by Parisian chemists 93 The characteristics of the gold of North Carolina, California, Colorado, and other American localities ; Australian gold, variations of and classification of mines ; Study of the natural alloys and accompaniments of gold 94 Two curious facts connected with gold affinities and alloys ; Gold extracted from galena found in Bucks County, Pa. ...... 95 Methods of treating gold alloys; Refining of gold in the United States Mint; Pettenkofer's statement regarding platinum found in extracted gold 96 Best admixture for smelting gold with saltpetre; Best size of quantity to be melted in one operation . . . . . . . . .97 Pettenkofer's recommendation for extracting gold and platinum from the slag 98 Re-melting gold containing osm-iridium ....... 99 Treatment of gold containing osm-iridium at the mint in St. Petersburg; Melting the dross resulting from the treatment of Californian and Australian gold containing gold, silver, and osm-iridium ; Separation of, according to d'Hennin ; Extraction of palladium from augentiferous gold CONTENTS.

X PAGE Use of cast iron in "parting" gold; Platinum vessels in parting gold by means of sulphuric acid ; Platinum vessels at the mint in Munich ; Treatment of auriferous silver at the mint in Munich . . . .101 Extraction of gold at St. Petersburg with cast iron vessels ; The discovery of and proving gold ores, necessity of "an eye for color" in exploitation for gold ; The simplest instrument for the discovery of gold in fine dissemination through sand or dirt . . • • • • .108 Gold cradle or rocker, illustrated and described 104 Sluice system of washing dirt with mercury ; Description of the wooden troughs ; Difficulty of amalgamation or combination of gold with other substances . . . . • - • • • ■ .105 Wurz's process of forming a hard amalgam; Crookes's process of forming a hard amalgam ............ 106 Poorer ores containing gold ; Treatment of poor ores . . . .107 Hungarian process . . . ... • • • • ■ • 108 Necessary precautions in the treatment of gold ..... 109 SILVER.

Occurrent form or appearance in nature; Native silver, characteristics of; Hardness, gravity, color, ductility, composition . . . . .111 Localities, geology, and associations ; Kongsberg Silver Mine, Norway . 112 Silver mines in the United States ; Arsenical iron or mispickel . . .113 Appearance ofthe principal ores of silver; Antimonial silver or dysracite . 114 Bismuth silver ; Freieslebenite ; Stephanite ; Argentite .... 115 Ruby silver or pyrargyrite ; Separation of the silver in the dry way ; Preliminary assay as described by Makins . . . . . . .116 Mitchell's preliminary assay ; Actual assay . . . . . .117 Assay of shop sweepings ; Scorification ; Makins's operation in . . 118 Cupellation of the noble metals . . . . . . . .120 Cupel furnaces, requirements of; Caution in working silver with lead . 121 Wet process or humid assay of silver ; Process of Haidlen and Fresenius for separating silver from copper ; Process where gold is in association . 122 Caution ; Recommendation of Rose, Ga)- Lussac, and Liebig on treatment of silver; To separate silver from lead . . . . . .123 Separation of silver from cadmium and bismuth ; From mercury . .124 Silver from sulphurets . . . . . . . . . .125 COPPER.

Native copper as a true ore, locations of, in the United States . . .125 Copper, characteristics of; Hardness; Behavior before the blowpipe; Geological position ; Usual compounded ores . . . . . . 1 26 Blowpipe and other detection of copper ; By dry method . . . 127 Wet method ; Caution . . . . . . . . . .128 Copper sulphides, decomposition of, and separation of sulphur . . . 129 Caution . . . . . . . . . . . . .131 CONTENTS. XI NICKEL. PAGE Nickel, characteristics of ; Ductility and tenacity ; Nickel glance (Gersdorffite) 132 The Speiss ; Oxides of nickel ; Chloride; Sulphides . . . .133 Alloys of nickel ; Separation of constituents in a nickel ore . . . 134 Deville's method of obtaining pure nickel; Ores of nickel found in the United States ; Decline in the price of nickel ..... 135 Use of nickel for culinary utensils ; For crucibles in chemical operations ; Consumption of nickel in the United States ..... 136 IRON.

Characteristics of iron ; Malleability, ductility, tenacity, etc.; The chief ores of iron ; The magnetic ores ; Magnetite ..... 137 Distribution and association of magnetic ores ...... 138 Hematite or red hematite (specular ore) ; The largest source of iron in the United States; Occurrence, characteristics, etc. . . . . .139 Brown hematite (limonite) ; Distribution, characteristics, and peculiarities 140 Limonite as a bog ore in the United States ; Spathic ore .... 142 Dry assay of iron ........... 143 Caution ............. 144 Choosing samples for experiments from an ore bed ..... 145 Wet method of assaying iron . . . . . . . . .147 Wohler's method of obtaining corroborative proof and accuracy . . 150 Examination for phosphorus ; In iron scsquioxide ..... 151 Parry's method for precipitating phosphorus . . . . . . 152 Deduction of pure iron in the assay . . . . . . . .154 Cautions 155 Examination for sulphur 156 Caution ; Determination of manganese 158 Spathic ore ; Kipp's apparatus for determining carbonic dioxide, illustrated and described ........... 162 Titanic acid (rutile) ; Dark -colored iron sand containing titanic acid ; "Where found, and treatment 164 Volumetric determination . . . . . . . . .166 Preparation of the reagents and of the test iron 16 7 Preparation of the ore for assay 170 Changing a ferric solution into a ferrous 171 Exhaustion of iron-ore deposits in the United States ; Remarks of Major Powell, Director of the Geological Survey 173 TIN.

Characteristics of pure tin 174 Occurrent form ; Stream tin CONTENTS. XII PAGE Localities and geology . . . . ■ • • • • .176 Greisen ; Block tin . . . . . . . • • .177 Tinstone; Where found; Wood tin; Analysis of an ore— Dr. F. A. Genth— from the Temescal tin mines, California ; Mineralogical appearance . . . . . . . • • • • • 1 78 Behavior before the blow-pipe . . . . . . . .179 Extraction for detection . . . . . . . . . .180 Estimating the quantity of tin in any compound 182 ZINC. Occurrent form ; Hardness; Gravity; Color; Ductility .... 183 Melting point; Impurities; Localities; Zinc sulphide found in isolated small pieces ........... 184 Silicate ; Carbonate of zinc ; Zinc sulphide or blende ; Under the blowpipe . . . . . . . . . . . . .185 Carbonate of zinc ; Silicate of zinc . . . . . . .186 Distilling zinc ; Apparatus illustrated and described ; Treatment of calamine or blende in the large way by the English method . . . 187 Belgian and Silesian processes ; Oxide of zinc ; Characteristics of . . 189 Proportion of metallic zinc in the oxide of zinc ; Pure metallic zinc . .190 Separation of metallic oxides of groups five and six . . . . .191 LEAD.

Lead; Properties of; Galena; Galenite . . . . . .194 Geological horizons and occurrence ; Geographical distribution of in the United States 195 Working the ore on the large scale . . . . . . . .196 Dry assay without iron ; Wet method ....... 197 Composition of lead sulphate . . . . . . . . .198 Constituents ofthe fumes passing off from lead ores; "Exhausters" of gaseous fumes ; Experiments with the Sturtevant blower . . . 199 Pattinson's process for separating silver from lead ..... 200 Parkes's process ; Hoffman's remarks on the use of Parkes's process in the United States ........... 201 Lead characteristics .......... 202 Wet assay and methods of detection ....... 203 To determine lead quantitatively ; Mascazzinie's method of assaying lead ore 204 MANGANESE. Manganese; Characteristics of ; Fusing with a blow-pipe ; Associations . 206 Its uses in the arts and manufactures . . . . . . .207 Its importance in the manufacture of steel ; Its effect upon building stone 208 Analysis for manganese by the wet process ; Process of detecting minute traces of manganese ..........

CONTENTS. XIII PLATINUM. PAGE Platinum and the combinations in which it is found ; Characteristics ; Hardness ; Lustre ; Color and streak 209 Geology and occurrence ; Where found in the United States in small quantities ............. 210 Analysis of California ore ; Wet process of analysis . . . .211 IRIDIUM. Its associations and characteristics; Hardness; Lustre; Malleability . 214 Table of a general view of the analytical process of separating the metals associated in the ores of platinum . . . . . . .215 Geographical distribution of iridium ; Its occurrence in the United States; Iridium ore in gold dust and the manner of separating .... 216 John Holland's important discovery in the melting of iridium ; Uses of iridosmine . . . . . . . . . . . .217 Iridosmine and iridium ; Relative values of .... . 218 MERCURY.

Occurrent forms and associations ; Hardness, gravity, color, ductility, composition ; Boiling and evaporating points . . . . . .218 Localities ; Geology and associations ; Rocks affording the metal and its ores; The strata of the Almaden mines, etc. ..... 219 Chemical characteristics ; Dissolution of with acids ; Combining with metals ; Oxides of 220 Ores ; Almaden mines in Spain and in California ; Cinnabar ore and its chemical affinities ; Treatment of the ore ...... 221 Retort process; Roasting the ore ; Rumford's cylinder furnace; Hiiffner & Scott's shelf furnace 222 Roasting fine ores with brick or adobes ; Intermittent furnace used at New Almaden, California , . . . 224 Rumford lime-kiln with its improvements explained by Saml. B. Christy; Characteristics of mercurial compounds; Testing insoluble substances for mercury ; Testing soluble bodies ; Action of stannous chloride ; Of potash, soda, or ammonia 225 Action of hydrochloric acid ; Of sulphide of hydrogen, or of ammonium sulphide; Makins's accurate method for determining mercury in compounds ............ 226 ANTIMONY.

Characteristics and occurrence of; Hardness; Gravity; Associations . 227 Stibnite ; Valentite ; Red antimony or kermesite ; Occurrence of stibnite, action before the blowpipe ; Antimony associated with cinnabar in California CONTENTS. PAGE Stibnite deposits in Utah ; Deposits in foreign lands .... 229 Extraction of antimony from its ores; Crocus of antimony; Uses and estimation of antimony ......... 230 Composition of antimony ; To distinguish antimony from Bismuth ; Makins's method of estimating antimony . . . . . .231 Caution in passing hydrogen sulphide through the hydrochloric solution . 232 BISMUTH. Occurrence and characteristics ; Hardness, gravity, lustre, streak, and color ; Brittleness ; Malleability ; Crystallization .... 232 Fusing point, and effect upon melting points of other metals ; Burning at a hinh temperature ; Effect of acids upon ; Expansion on cooling after fusion; Detection of bismuth; Its salts; Action of dyhydric sulphide or ammomo-hydric sulphide ; Action of the alkalies, potash, soda, or ammonia ; Action of potassic chromate ; To distinguish bismuth from lead 233 Behavior under the blowpipe ; Occurrence of bismuth in the United States ; Its use in alloys and amalgams ; Subnitrate as an enamel in porcelain, etc. 234 CHROMIUM.

Chrome iron or iron stone ; Composition of ; Chromite ; Hardness, gravity, lustre, streak, color ; Action before the blowpipe .... 235 First notice of its occurrence in the commercial way ; Deposits in Maryland and Pennsylvania ; Decomposing the ore ; Deposits of chrome ore in North Carolina, Virginia, and California ..... 236 Quantitative analysis of chrome iron ore . . . . . .237 COBALT. Cobalt generally associated with nickel ; Cobalt glance, and smaltine ; Zaffre ; Preparation of the metal ....... 238 Color, specific gravity, fusibility; Localities of cobalt minerals; The only use of cobalt ; Inability to plate with ; Value of cobalt and of cobalt oxide ; Detection of its compounds by the blowpipe .... 239 Separation of cobalt from nickel ........ 240 CORUNDUM AND EMERY. Corundum and Emery ; Simply alumina with various degrees of associated iron oxide; Corundum in its purest crystalline state; Color, hardness, gravity, lustre ; Action under the blowpipe ; Solution in borax and salt of phosphorus ; Color produced by long heating with a cobalt solution ; Association with crystalline rock ; Emery at Chester, Mass. . . .241 CONTENTS.

XV PAGE Corundum in North Carolina, Georgia, and other States ; Guide or sign in searching for ; Uses of corundum and emery ; Preparation of ; To test the abrasive power of a corundum sample 242 Exports and imports of emery, 1883, 1887 243 PUMICE STONE. Deposit of, near San Francisco ; Composition of pumice stone imported from the Lepari Islands; Gravity, color; Value of imports, 1883, 1887 . 243 Rotten stone, Tripoli, description and statistics of; To gain a knowledge of pumice and of rotten stone ......... 244 INFUSORIAL EARTH. Composition of; Analysis of by J. M. Cabell; Deposits found in the United States ; Uses of this earth in the manufacture of polishing powder, sand soap, etc. .......... 244 GRINDSTONES. Description of principal source of supply ; Stone found near Grindstone City and near Marquette ; Statistics of total imports and of home production 245 BUHR STONES.

Leading localities in the United States ; Æsopus stone .... 245 Cocalico found in Lancaster County, Penna. ; Berea Grit, found in Summit County, Ohio ; Uses of the American stone and of those imported ; Substitution of rollers for buhr stones ; Statistics ; True buhr stone . 246 THE DIAMOND. Diamonds found in the United States ....... 246 Association of minerals generally with the North Carolina diamonds ; Dr. Genth's description of the debris; Hardness, gravity, lustre, color, and general appearance of monazite . . . . . . . .247 Composition of and behavior under the blowpipe; Xenotine, characteristics and general appearance of; Octahedrite, hardness, gravity, lustre, color, streak, and composition of ; Behavior before the blowpipe; Color produced by fusion with an alkali or alkaline carbonate ; Rutile . . 248 Diamonds found in Georgia, California, Idaho, Wisconsin, Montana, and Arizona; Gravity; General appearance when found . . . .24 9 One of the best tests of a diamond; Appearance of the diamond in the rough state ; Their ability to scratch glass no proof of their distinctive value as diamonds ; Other glass-scratching stones ..... 250 Diamonds found in clay in the diamond fields of Africa .... CONTENTS. XVI

Part II. Mining Work And Architecture, Including Various Suggestions, With Description Of

ASSOCIATED APPARATUS AND MACHINERY. MINING CONSTRUCTION AND MACHINERY.

PAGE Introduction ............ 255 Some explanation of terms ; Agangway or gallery, illustrated and described ; German, Austrian, English, and American names .... 256 Preliminary work and considerations ; To make trial shafts or excavations 257 Employment of borings by proper machinery ; Examinations for drainage ; Protection of the excavations and supply of timber or of masonry ; Accessibility to market one of the most important elements of successful mining ............ 258 Importance of drainage ; Grade or descent necessary to prevent overflow ; Construction of the main gallery ........ 259 Location and size of the galleries; Opening a gallery from the side of a hill, illustrated and described ; To begin the galleries when opening upon a vein or lode ; Working a mineral vein upward from the floor of a drift gallery . 260 Inclination of galleries running at right angles to drifts ; Sinking a slope from the top of a hill, illustrated and described.; When the gallery is entirely in the lode to be worked out ; While the gallery is partly in the rock and partly in the lode ; Putting the gallery outside when the lode is weak ; Putting the gallery within the lode when the rock is stronn* ; AVhen the rock is not in horizontal strata ...... 261 Building a gallery at a distance from and parallel to the pay rock, illustrated and described .......... 262 Leading off* the water from mines, illustrated and described ; Where expedition is required, illustrated and described ...... 263 Vertical distances between galleries built over each other ; Extracting water when the lowest gallery runs beneath the level of the water outside ; Names of the galleries ; Recommendations to be observed when making oreways into the shaft, between the usual lifts ; Economic use of pumping machinery .......... 264 Shaft method when entrance upon mineral lodes cannot be made by drifts ; Possible forms of Mining when rock is to be penetrated ; Shafts intended for entrance of light .......... 265 Proper position of the "sumpt" or drain reservoir; Advantage of the slope over the perpendicular shaft ; Cross-section of shaft framing, illustrated and described ..........

Contents

XVII PAGE Use of a straight and vertical shaft for experimental and permanent purposes, illustrated and described ; Shaft when the ore seam appears of an undetermined angle, illustrated and described 26 7 Slope in the coal beds, illustrated and described ; Opening of the shaft in rock or soil, illustrated and described 268 Sinking of side-pits when the roof is weak, illustrated and described ; Timbering ; Depth and width of the dumping-floor 269 Leading off the water from side walls, illustrated and described _ . 270 On the opening of mines . . . . . . . . .270 Important rules to be observed in opening or exploring a mine ; The most important changes in ore veins ; Splitting, forking, or scattering of a vein; Compression or pinching of the vein ...... 271 Shifts or faults ; When a vein divides into several branches ; When a vein becomes pinched or thin ; When a vein or lode is intersected by another and the continuation of the one in progress cannot be found in the same direction 272 Distinction to be made between the gangue and ore in opening a deposit of mineral, illustrated and described ; Special consideration of the rise or inclination of the ore in opening a lower foot drift, illustrated and described ............ 273 To locate the opening of a deposit when the mountain is steep and the strike of the vein is parallel with the slope of the mountain ; When the strike of vein is across the strike of the mountain ridge ; When the deposit is greatly inclined or strikes under a plain ; When the deposit is nearly horizontal . . . . . . . . . .274 Opening of large irregular deposits ; Guidance for mining when nests or kidneys of ore lie separate from each other ; Requirements of well-conducted, scientific, systematic mining ; Advantage of going to the lower parts of the deposit as soon as possible ...... 275 Requirements of systematic mining both during the opening and the actual working of the mine ; Value of transverse galleries, cross-clefts and fissures ............. 276 Final preparations and working of mines . . . . . .277 Stoping out the ore ; Division ofthe deposits by levels, drifts, etc. ; When a mine is said to be exposed ; Establishing a correct relation between the preparatory work and the extracting of the ore ..... 277 Judicious treatment ofthe exposed ore; To make an average between the higher and lower, richer and poorer ores ; Evil results from "robbing a mine" ............ 278 Regulations for locating the work and employment of hands ; Provisions for drainage, ventilation, security ofthe mines and lives of the miners . 279 Veins and lodes ; How prepared and mined 279 Mining the ore if the vein be not over twelve feet thick, illustrated and described ............ 279 E CONTENTS.

PAGE Commencing the final work of exhausting the mine .... 280 Mining overhead, or by ascending steps, illustrated and described . . 281 Method of working downwards, illustrated and described .... 283 Working when the vein has a selvage or partition rock ; AVhen the vein is firmly attached on both sides to the rock ; Advantages and disadvantages attendant upon each method of mining ...... 284 Working when the ore is not uniformly rich, or is deposited in small detached masses, illustrated and described ; When lodes are more than two or three fathoms in thickness, illustrated and described . . . 285 Treatment of the breast when it reaches the wall or is abandoned ; Opening of a second story immediately over the first, illustrated and described 286 AVorking when a large mass of barren rock is met in the deposit, illustrated and described . . . . . . . . . . .287 Preparation and working of stratified deposits and beds .... 287 AArorking of beds of great inclination ; When the inclination is less than forty degrees : Long wall system or post and stall workings . . . 287 Detailed working of the long wall system, illustrated and described . . 288 AVhen the long wall method is used ; Use of the post and stall method ; Preparatory work for the post and stall method, illustrated and described 289 Taking out the pillars ; Operation when the roof is brittle ; Cutting levels and drifts in coal-beds, illustrated and described ..... 290 In coal-beds of different layers and benches illustrated ; In beds of very great thickness, illustrated and described ; Supporting the roof or walls ; Spontaneous combustion, generally supposed cause of, and the most effective mode of prevention . . . . . . . .291 Preparation and working of mineral deposits that occur in large masses . 292 Mining large deposits possessing some degree of regularity ; Deposits with little or no regularity in form ; Preparing a deposit to work from below upwards, illustrated and described ; AVhen the deposit has been discovered by means of an adit or tunnel ....... 292 AVhen the deposit has been discovered by a shaft ; Arrangement of the floor and pillars ; Position of the miners when at work ; Operation when a vault becomes too large or in danger of crushing in, or the ore-mass is composed of hanging and lying ore-veins ; To gain masses of inferior ores difficult of extraction ......... 293 To gain valuable ore after the mine has crushed in ; Rock-salt works containing salt in large and almost pure masses, operation, illustrated and described .......... 294 Gaining the salt in a mine by dissolving it ; Running of gangways with rectangular branches conveying water, illustrated and described ; Rock blasting ; Method used in progressing against a breast in a gangway of a salt mine, illustrated 295 Preparation and working of nests, cores, or pockets 295 Surface or day working CONTENTS.