None
Copper Dsrsprosium Erbium Europium.. Fluorine Qadolinium. QalUum Germanium Gluoinum.. Gold Helium. . .. Holmium. .. Hydrogen.. Indium Iodine Iridium Iron Krjrpton — Lanthanum. Lead Lithium.... Lutecium. .. Magnesium. Manganese. Mercury. .. Al Sb A As Ba Bi B Br Cd Cs Ca C Ce a Cr Co Cb Cu Dy Er Eu F Gd Ga Ge Gl Au He Ho H In I Ir Fe Kr La Pb Li Lu Mg Mn Hg 27.100 120.200 30.880 74.900 137.370 208.000 11.000 79.020 112.400 132.810 40.070 12.005 140.260 35.460 52.000 58.970 03.100 63.570 162.500 167.700 152.000 19.000 157.300 69.900 72.500 9.100 197.200 4.000 163.500 1.008 114.800 126.920 193.100 55.840 82.920 139.000 207.200 6.940 175.000 24.320 54.930 200.600 M^bdenum Neodymium Neon Nickel Niton (radium emanation) Nitrogen Osmium Oxygen Palladium Phosphorus Platinum Potassium Praseodymium Radium Rhodium Rubidium Ruthenium .« Samarium Scandium Selenium Silicon SUver Sodium Strontium Sulphur Tantalum Tellurium Terbium Thallium Thorium ThuUunl Tin Titanium Tungsten Uranium Vanadium Xenon Ytterbium (Neoytterbium) Yttrhim Zinc Zirconium Mo Nd Ne Ni Nt N Os O Pd P Pt K Pr Ra Rh Rb Ru Sa 8c Se Si Ag Na Sr S Ta Te Tb Tl Th Tm Sn Ti W U V Xe Yb Yt Zn Zr 96.000 144.30 20.20 58.68 222.40 14.01 190.90 16.00 106.70 31.04 195.20 30.10 140.90 226.00 102.90 85.45 101.70 150.40 44.10 79.20 28.30 107.88 23.00 87.63 32.06 181.50 127.50 159.20 204.00 232.40 168.50 118.70 48.10 184.00 238.20 51.00 130.20 173.50 88.70 65.37 90.60 244 MANUAL OF CYANIDATION WEIGHTS AND MEASURES, ENGLISH AND AMERICAN SYSTEM Linear Meastsre 12 inches 1 foot 3 feet ; 1 yard 5 . 6 yards , 1 rod 40 rods 1 furlong 8 furlongs 1 mile Inohee Feet Yards Rods Furloncs Mile 36 3.0 1.0 198 16.5 5.5 1 7920 660.0 220.0 40 1 {,360 5280.0 1760.0 320 8 Square Measure 144 square inches 1 square foot 9 square feet 1 square yard 30H square yards 1 square rod 160 square rods 1 acre 640 acres 1 square mile Cubic Measure 1728 cubic inches 1 cubic foot 27 cu. feet 1 cubic yard Avoirdupois Weight English 437 .5 graios 1 ounce (oz.) 16 ounces 1 pound Qb.) 14 pounds 1 stone (st.) 28 pounds 1 quarter (qr.) 112 pounds 1 hundredweight (cwt.) 20 cwt. (2240 lb.) 1 ton (T.) American 437.5 grains 1 ounce (oz.) 16 ounces 1 pound Qb.) 100 pounds 1 hundredweight (cwt.) 20 cwt. (2000 lb.) 1 ton (T.) TABLES 245 Troy Weight 24 grains 1 pennyweight (dwt.) 20 penn3rweight8 1 ounce (oz). 12 ounces 1 pound (lb.) 1 lb. Troy 6760 grains 14 . 5833 oz. Troy 1 lb. avoirdupois 29,166.6 oz. Troy 2000 lb. avoirdupois Liquid Measure 4 gills 1 pint 2 pints 1 quart 4 quarts 1 gallon 1 U. S. gallon— 231 cu. m.— 0. 134 cu. ft. 1 cu. ft.— 7 . 481 U. S. gallons 1 British imperial gallon— 277 . 274 cu. in.— . 16046 cu. ft. 1 cu. ft. — 6 . 234 imperial gallons 1 cu. ft 62.42 lb. of water 1 ton (2000 lb.) 32.04 cu. ft. of water 1 ton (2000 lb.) 239.69 U. S. gallons THE METRIC SYSTEM Linear Measure 10 millimeters (mm.) 1 centimeter (cm.) 10 centimeters 1 decimeter (dm.) 10 decimeters 1 meter (m.) 10 meters 1 decameter (Dm.) 10 decameters 1 hectometer (Hm.) 10 hectometers 1 kilometer (Km.) Square Measure 100 square millimeters (mm.*) 1 square centimeter (cm.') 100 square centimeters 1 square decimeter (dm.') 100 square decimeters 1 square meter (m.*) Cubic Measure 1000 cubic millimeters (mm.») 1 cubic centimeter (cm.* or cc) 1000 cubic centimeters 1 cubic decimeter (dm.*) 1000 cubic decimeters 1 cubic meter (m.*) 246 MANUAL OF CYANIDATION Liquid Measure 10 miUilitres (ml.) 1 centilitre (cl.) 10 centilitres 1 decilitre (dl.) 10 decilitres 1 litre (1.) 10 Htres 1 decaUtre (Dl.) 10 decalitres 1 hectolitre (HI.) 10 hectolitres 1 kilolitre (Kl.) 1 litre 1000 cubic centimetres . * 1 cu. ft. of water 28.317 litres 1 litre of water 61.023 cu. in. = 0.03531 cu. ft. 1 metric ton of water 35.319 cu. ft. 1 metric ton of water 264.2 U. S. gallons Meastire of Weight 10 milligrams (mg.) 1 centigram (eg.) 10 centigrams 1 decigram (dg.) 10 decigrams 1 gram (g.) 10 grams 1 decagram (Dg.) 10 decagrams 1 hectogram (Hg.) 10 hectograms 1 kilogram (Kg.) 1000 kilograms 1 ton (T.) 1 gram » the weight of 1 cubic centimeter of pure distilled water at a temperature of 4® cent. 1 kilogram = the weight of 1 litre of water 1 ton = the weight of 1 cubic meter of water CONVERSION TABLES Linear Measure 1 in 2.53998 cm. 1 cm 0.3937043 in. 1 ft 0.30479 m. 1 m 39.37043 in. 1yd 0.914399 m. Im 3.28083 ft. Imi 1.60934 km. Im 1.09362 yd. 1km 0.62137 mi. Square Measure 1 centar (1 sq. m.) 1550 sq. in. — 10. 764 sq. ft. 1 ar 119.6 sq. yd. 1 hectar 2.47104 acres 1 sq. cm 0. 155 sq. in. 1 sq. meter 10.76390 sq. ft. 1 sq. km 0.3861 sq. mL 1 acre. 0.40469 hectar 1 sq. in 6.4516 sq. cm. 1 sq. ft 0.092903 sq. m. TABLES 247 Cubic Measure 1 cu. in 16.38720 cc 1 cc 0.06102376 cu. in. 0.0000353 cu. ft. 1 cu. ft 0.028317 cu. m. 1 cu. m 35.31445 cu. ft. 1 . 30794 cu. yd. 1 cu. yd 0.764553 cu. m. Liquid Equivalents 1 fluid ounce 29 . 5737 millilitres 1 millilitre 0.03381 fluid ounce— . 061027 cubic inch 1 quart 0.94636 litres 1 litre 1 .0567 quarts 1 U. S. gallon 3.78543 litres 1 litre 0.26417 gallons Dry Equivalents 1 hectolitre 2.8377 bushels 1 U. S. bushel 0.35239 hectolitres Weight oz. avoirdupois 28.34954 grams lb. avoirdupois 453 . 59 grams (short) ton 907. 18 kg. gram 0.035274 oz. avoir.— . 00220 lb. kg 35.27392 oz. avoir.— 2 . 2046223 lb. metric ton 1. 1023 11 short ton— 0.9842 long T. grain 64 . 799 mg. dwt 1 . 55518 grams oz. Troy 31 . 1035 grams lb. Troy 0.37324 kg. gram 15.4324 grains— . 64301 dwt. gram 0.03215 oz. Troy kg 32.15076oz.Troy— 2.679231b.Troy oz. Troy per ton'of 2000 lb. — 34.285 grams per metric ton 248 MANUAL OF CYANIDATION Table 30. — Assay Conversion Table Per cent. Grams per metric ton (lOOOkiloe) Oi. Troy per long ton (2240 lb.) Oi. Troy per metric ton (2204.61b.) Oa. Troy per short ton (2000 lb.) 1 per cent 1 gram per metric ton 1 OI. Troy per long ton 1 OS. Troy per metric ton 1 OS. Troy per short ton 1 dollar per short ton (gold at f 20.67 per os.) 1.00000 0.00010 0.00300 0.00310 0.00340 0.00016 10,000.00 1.00000 30.61200 31 . 10348 34.28500 1.66000 326.66600 0.03266 1.00000 1.01600 1.12000 321.50700 0.03215 0.98420 1.00000 1.10200 0.05400 0.05300 291.66600 0.02916 0.89280 0.90710 1.00000 0.04800 VARIOUS FORMULAS Area of a Circle Radius* X 3.1416 or Diameter* X 0.7854 Circumference of a Circle ^ Diameter X 3.1416 Cubic Contents of Cylindrical Tank Area X depth Cubic Contents of Cone Area of base _ , ^, o X depth CALCULATION OF RECOVERY IN CONCENTRATE Let C — assay value of concentrate I^t H = assay value of head Let T = assay value of tailing Let R — Ratio of concentration Let W — weight of concentrate (per cent.) Let P = percentage recovery Let L = percentage loss in tailing R = W = P - P = H - T ^ " I X 100 C — T 100 X C{H - T) H(C- T) C X 100 HXR 100 X T(C - H) H(C-T) TABLES 249 EUnunation of Iifiddliiig by Calculation. — This is based on the assumption that the return of the middling to the head of the concentration system does not change the subsequent assay value of the concentrate and tailing. The weights of the various products and the assay of the middling need not be known. Let X and Y = percentage weights of concentrate and tailing respectively when middling is eliminated. Let hj c, tj = assay values of head concentrate and tailing respectively. Let X and y = percentage of total values in concentrate and tailing when middling is eliminated. 100 (h - t) „ 100(c - h) X = c - t Y = X — 100 (h - t)c y c - t 100(c - h)t h(c - " A(c - t) Power. LH.P. — 33,000 foot-poimds per minute « 4562.33 kilogram meters per minute = 0.746941 kilowatts = 1.01385 metric h.p. 1 metric h.p. = 32,549 foot-pounds per minute = 4.500 kilogram meters per minute = 0.735750 kilowatt = 0.98634 h.p. Pressure. — 1 atmosphere = 760 millimeters, or 29.922 inches of mercury column = 10.333 meters, or 33.901 feet of water column = 14.696 pounds per square inch = 1.0333 kilos per square centimeter. 1 pound per square inch = 0.070310 kilo per square centimeter. 1 kilo per square centimeter = 14.223 pounds per square inch. Table 31. — Miscellaneous Figures on the Weight op Broken Ore (Richards "Ore Dressing", Weight per cubic foot. lb. Cubic feet per ton Material 100 100 100 96 95 87 77 75 Mine ore coming to Mill, North Star Mining Co. Tailings of Mill, Calumet and Hecla Mining Co., Michigan. "Blue ground" (altered peridotite) as it comes from the Kimberly mines. South Africa. Broken quartz as it comes from the Jumpers' Deep mine. South Africa. Broken quartz conglomerate as it comes from the Ferreira mine, South Africa. Material from gravity stamps. Material from gravity stamps, with the slimes removed. Quartz stamped dry through 40 mesh and charged dry into vats at the Victoria mill, Hauraki penin- sula. New Zealand. 250 MANUAL OF CYANIDATION o o CO H •S s p o O -6 a o C8 O .a a o a c s « 5 &^ .•Sow •>4 «» 1 1 1 1 .1 5 « !» 5 -S ■5- * Oh a 3 GO GO "2 O ■M •§ ^ « « O « 2 IS "o 'o "O •a O a a < at a 2 5 ^ s ftOQ 3 OQ 1 1 1 1 -1 o a a < "S S. 08 O I a TABLES 251 "I H 2 -< H H CO Eh S cS I tIj V SB 08 9 a O •3 a a o a o 5 s ? CO Q o I a d o to CD to ^ lO J^ >0 lO t t "^ "^ f ub lO <0 CD 16 IQ CO CD CD CO »o CD 10 CD J^ CO 10 >0 ub 10 >o to 10 to to "^ti«J to CO b<i to • I • • 1-1 CO o< o< to to «' ^ N C9 to to C9 to CO CO • • • t* ^ CO d» to « eo 1-t • ^ to ^ r* «* to t« O) ^ ... CO tH CO CO t* *H CO C4 00 a o t^ «o M ^ ^ CO « C9 m « •O - „ • OQcSoQQa 9) J» <D « « P^ pE( pE( p^ Pm O » d * g i? 5 «.-s .TS -^ •*» o ^ « 1 § I 5 1i a S^-Ese I? |5|.|:i •a 'a 2 a s II 2 -S > .f4 .^ '^ ct o cS •S a a 2 >»i? o o tf « « _S Q '2 "g "g • « « 2 2 a a •o "d •© "S Oi o. Oi O O 00* w * 5 s 5 J? 2 ^ ^ «! ^ iS ^ ^ O" SB .fi^ S .M .»■ r. GO QQ M m m m I I ^ 5^- a GQ * 9 a O O ^ N o ■So GQ fcQ OQ fcq m 6Q 5 S .^ 'S ^ '& § 5 •2 o CG S 2 • ct I .a 00 < .•2 5 •a I 9i DO a C M 0) S < O .it .A n eg ^ ^ a fl flS o £ S V ^ o ^a^'a^i^a d 08 o a ® •d 4) a i a 2 « O GQ fe 3 S o OS « IS V d i '•§ 2 « « O GQ fcq QQ OQ I QQ d d a; d 3 d 64 TABLES 253 I I 1 8 § &'3 cS ►« i .9 a « •a a 1 o •a o •5: •3 o o cS ► 3 o a> ^ s 8. . . 3 00 ^ &) 5 0Q i g i a> cS 0) M 1! to I 10 •o ^ M J^ o I « CO o 0> eo O q CM •o 10 10 CO i o t^ CO Jb 10 ^ >o >o C4 CO t^ CO M »o CO CO CO csi CO CO M «0 ">* C^' CO CO I SJl, CO ■«»• 0« q 00 10 I 00 Cl IQ CO • O i-^ I CsJ .1 CO M 08 a o o CO o o M .a Id ■3 o + O 03 o o QQ O O a M O QQ ao| <5 o M M d •J I a 6 I 9 ■*» 08 0) •5 '^ II ffl <j ^^ — ^ Si a OD >» >• OS o •n OS 08 a I o a a 9 « 08 d o .0 a 9 *i .§ 's 3 IS — § a s •3 .2 1 .? ss o ^ 13 o OS 03 •a OD a 9 •s •3 o a « 8. I a 9 •35 08 d o «8 CO V d 08 •8 9 08 -9 08 •g o S o ^ -3 3 s 3 ;S 3 d o 08 o d a 'g os 9 s oS <«» 08 gg ^ « w .^ OB S h s S 3 s ^ — % s a o 08 1 I 5 i o •3 I* II 6l 9 ■§ 9 a 9 OD o d 0) 08 5 a d » .3 s o o a ffi m (^ 1 • •3 I S » • 9 ^ a 'S '9 .2 sal -I o 5 INDEX Accumulated dam-slime, treatment, 89 ** tailings, leaching prac- tice, 70 Accumulation of zinc in precipita- tion, 176 Acetates, formed by heating of solu- tions,. 10, 45 in cyanide solutions, esti- mation of, 45 Acid preliminary treatment in cyani- dation of concentrate, 170 " treatment clean-up tank, 202, 203 " " for "zinc shorts," 203 " " of Butters filter leaves avoided by use of special leaf, 112 Acid-sulphate of soda for treatment of zinc precipitate, 203 Adams, Huntington, method of transfer in continuous agitation, 100 Addition of cyanide during bottle agitation, 219 " " water to stock solution, 124 Advantages of aluminiimi precipita- tion, 197 ** zinc dust as a pre- cipitant, 185 ti Aeration, for removal of soluble sulphides in solution, 192 in bottle agitation, 216 in slime treatment, 89 of sand charges, 68 " " " Homestake practice, 61 " " "in laboratory tests, 226 " preliminary to cyanida- tion of concentrate, 170 Agitating devices for slime pulp, 89 Agitation period in slime treatment, 99 tests, 216 " large scale, 229 Agitator tank for aluminium precipi- tation, 192 " " clean-up, 202 " " "zinc shorts," 182 wheel for bottle tests, 216 Air prejudicial to aluminium pre- cipitation, 194 " vent for leaching tanks, 67 Air-lift data, Allen, 240 " " for aeration in slime treat- ment, 89 " " " leaching tanks, 68 Akins classifier, 65 Alkali consumption tests, 218 " free, effect in titration for cy- anide, 21 in solutions, regenerative ef- « tt it tt it it 255 256 INDEX (< << il it II H it tt << l( tt tt tt Alkali feet on zinc cyanide solu- tions, 6 protective, determination, 26 Alkaline sulphides as harmful reduc- ing agents, 5 as solvents for gold precipi- tated by graph- ite, 15 estimation of, 46 in aluminium pre- cipitation, 1^ present simulta- neously with silver in cya- nide solution, 2 reaction with lead salts, 14 " with solu- tions from zinc precipita- tion, 176 regenerating ef- fect on zinc cy- anide solutions, 6 Allen, A. W., air-lift data, 240 '' All-sliming," 73 tests, 221 Aluminate, calcium, in aluminium precipitation, 191, 198 sodium, 191 Aluminium as precipitant in cyani- dation of silver con- centrate, 171 dust, to precipitate sil- ver in the zinc deter- mination, 31, 32  Aluminium precipitation effect on slime filters, 198 " " forarsenic- and an- timony- sil V er ores, 168 " reactions, 190 use in the desulphurizing process, 166 Alvarado Mining and Milling Com- pany's Reduction costs, 235 Amalgamation, applied to telluride gold ores, 157 in cyanide solution, 123 in lime water, 77 test for gold, 213 American Continuous Filter, 116 Ammonia distillation, for determina- tion of cyanates, 41 Ammonium formate, a product of cyanide decomposi- tion, 12 salts, formed by decom- posing cyanates with acids, 41 " in cyanide solu- tions, determin- ation of, 43 Anodes in electrolytic precipitation, 186 Antidote for cyanide poisoning,  anide solutions, 8 " influence of, in cyanida- tion of gold ores, 162 Antimony- and arsenic-silver ores, 166 .< n li (< << laboratory test for effect on solu- tions, 227 Antimony-lead anode in electrolytic precipitation, 189 Application of solution to leaching tanks, 67 Arsenic and antimony in silver ores, 190 effect on efficiency of cya- nide solutions, 8 influence of, in cyanidation of gold ore, 162 Arsenic- and antimony-silver ores, 166 << a II n ti ti ii laboratory tests for effect on solu- tions, 227 Ashes from furnace, disposal of, 210 Assay conversion table, 248 " of slime residue, error in, 154 " " solutions for gold and sil- ver, 52 Atmospheric oxidation to assist the dissolution of gold and silver, 3 Atomic weights, 243 Aurocyanide, carbonyl, 15 Aiiropotassic cyanide, 1 Australian practice in slime treat- ment, 107 Automatic pulp sampler, 146 " weighing of ore, 130 Available alklinaity of lime, 29, 218 B Barren plant solution, for laboratory tests, 228 17 Base metals, effect on efficiency of cyanide solutions, 8 Basic ferric sulphate a source of ferrocyanide formation, 13 Beauchamp, F. A., treatment of graphitic concentrate, 15 Berthelot, investigations on solubil- ity of silver in presence of potas- sium sulphide, 2 Bettel, W., hydrocyanic acid deter- mination, 25 Betty, W. K.,the zinc-lead couple, 178 Bicarbonate of soda in fluxing pre- cipitate, 206 Bicarbonates, not classed as protec- tive alkali, 11 Blaisdell Excavator, for discharging sand residues, 72 Blyth, W. B., influence of arsenic in cyanidation of gold ores, 162 Bottle agitation tests, 216 Briquetting precipitate for melting, 208 Broken ore, weight of, 249 Bromide salts, for -preparation of bromocyanide, 159 Bromocyanide, as an oxidizing agent, 4 " in treatment of tellu- ride gold ores, 4, 157 reaction with alkali, 158 treatment, improve- ments suggested, 161 Brown slime agitator, 91 Bucking table for wet-grinding of samples, 215 Bullion bars, sampling of, 209 Bullock, L. M. B., method of pack- ing zinc boxes, 181 Burt filter, 116 (( << 258 INDEX Butters and Mein distributor, 55 " as a collector of deslimed sand, 57, 62 Butters, Charles, method of slime treatment, 88 Butters Divisadero Company, ex- periments on relative efficiency of sodium and potassium cyanides, 17 Butters Divisadero Company, prac- tice in aluminium precipitation, 195 Butters filter, draTybacks, 110 " " special leaf to obviate acid treatment, 112 Butters vacuum filter, 108 Calcining zinc precipitate, 204 Calcium aluminate in aluminium precipitation, 191, 198 " carbonate on leaching tank filter cloths, 70 " zincate formed in solutions from zinc precipitation, 6, 176 Calculations for dissolved value loss in Dorr counter-cur- rent system, 118 " of Mill heads value by difference, 152 Caldecott, W. A., error in assay of pulp containing soluble gold, 154 investigation in treatment of dam-slime, 89 reaction of lead sulphide in cy- anide solution, 14 " " separating cone, 61,63 i( << (< (( (( n u Caldecott, W. A., Table, weights and volumes of slime pulp, 134 ** ** vacuum filter for sand, 62 Capacity of Dorr thickeners, 79, 81 " " zinc boxes, 183 Capillarity effect in sand percola- tion, 69, 226 Carbonate of zinc and calcium, formed in solutions from zinc pre- cipitation, 176 Carbonic acid, a decomposer of cy- anide, 11 Carbonyl aurocyanide, 15 Carpenter, J. A., improvements in Trent agitator, 96 Cathodes in Minas Prietas electro- lytic practice, 186 " " Siemens-Halske precipi- tation, 186 Caustic soda, formed in Crosse's cy- anide regeneration process, 7 " in aluminium precipi- tation, 190 " reaction on steel pre- cipitation boxes, 181 Charcoal, a precipitant of gold from cyanide solutions, 15 " method of precipitation, 199 Charging crucibles with precipitate, 208 Chemical oxidizing agents, as aids to the dissolution of gold and sil- ver, 3 Chiddey-Magenau method of solu- tion assay, 53 Chloride of silver, reaction with cy- anide solution, 1 (I « INDEX 259 Chloridizing roast for refractory manganese ores, 164 " ** " silver con- centrate, 1169 Circles, formulas, 248 Clark, A. J., and Sharwood, W. J., Homestake slime process, 105 Clarification of solutions for precipi- tation, 173 Classifier, the Akins, 65 " Dorr, 64 " Dorr washing, 66 Classifiers, mechanical, 63 Cleaning up the zinc boxes, 182, 202 Clean-up in charcoal precipitation, 201 Clennell, J. E., action of air on cy- anide solutions, 11 '^ " ^^ amalgamation in cyanide solution, 123 " ** " determination of ammoniimi salts in cyanide solutions, 43 " " method of reducing iron, 38 '' " '' '' titrating cyanide solutions containing cop- per, 23 Clennell, J. E., on copper determin- ation, 33 " " " formation of ace- tates in cyanide solutions, 45 " " " making decinor- mal solution of iodine, 31 specific gravity determination of dry ore, 132 n n (( It tt It tt tt tt Clennell, J. H., on "total" cyanide determination, 24 '* " " reactions in titration of bromocyanide, 158 Clennell, J. E., reactions in zinc pre- cipitation, 174 " " " reaction of c o p p e r with cyanide solution, 12 Clennell, J. E., reaction of lead salts with silver sulphide, 14 Clennell, J. E., relative efficiency of metallic cyanides, 16 " '' " titration for protec- tive alkaU, 27 Clevenger, G. H., agitator for bottle tests, 216 " " experiments on Nipissing silver ore, 166 " '' method of pour- ing crucibles, 209 Clevenger, G. H., Young, H. W., Turner T. N., error in density de- termination of slime due to specific gravity of solution, 140 Coagulation of slime, 76 Coarse gold, 214 Coe, H. S., and Clevenger, G. H., on calculating capacity of slime thick- eners, 80 Colbath, J. S., zinc dust precipita- tion, 184 Collecting tank for sand, 55 '^ ** " the Hamil- ton, 59 Colloidal material estimated by pan- ning, 220 Colorimetric detection of gold in cy- anide solutions, 53 estimation of copper, 35 tt ti 260 INDEX Colorimetric estimation of iron, 37 '■ silver in cyanide solutions, 54 Commercial considerations in "all- sliming," 74 Compression phase in slime thicken- ing, 80 Computation of cyanide consump- tion in laboratory tests, 222 Concentrate, cyanidation of, 169 Concentration, formulas for calcu- lating recovery, 248 " tests, 227 Cone classifiers, the Merrill, 60 '' the Caldecott, 61, 63 *' formula for cubic capacity of, 248 Consumption of cyanide, at anode in electro- lytic precipi- tation, 189 by atmos- pheric oxidation, 11 Consumption of cyanide, by base metals, 12 Consumption of cyanide, by heating of solutions, 5, 10 Consumption of cyanide, by hydrol- ysis, 11 Consumption of cyanide, by me- chanical loss, 10 Consumption of cyanide, by metallic ' iron, 12 due to silver in laboratory tests,224 Consumption of cyanide, due to un- necessarily strong solutions, 9 Consumption of cyanide, in cyanida- tion of concen- t r ate , 170 II n Consimiption of cyanide in labora- t o r y tests, 222 " " *' in treating silver ores, 10 " " " inzincpre- ci p i ta- tion, 10 Contact period in sand leaching, 68 Continuous agitation, 99, 102 " ** and counter- current de- cantation, 117 Conversion table, Fahrenheit to Centigrade, 242 tables, weigh ts and measures, 246 ** assay weights, 248 Copper, action in zinc precipitation, 178 colorimetric estimation, 36 determination in cyanide solutions, 33 effect on efficiency of cyan- ide solutions, 8 elimination in sulphocyan- ate determination, 40 in aluminium precipitation, 197 " " charcoal precipitation, 200 " " the cyanidation of con- centrate, 171 reaction with cyanide solu- tions, 12 titration of cyanide solutions containing, 23 solutions at the Minas Prie- tas plant, 186, 188 (< << It tt (t tt tt tt INDEX 261 (< tt Corrections for specific gravity of solution in slime pulp determina- tion (Table), 142 Costs, general reduction, for various mills (Tables), 233 in the Denny desulphurizing treatment, 168 of aluminium precipitation, 198 Cottrell precipitator in chloridizing roasting, 165 Counter-current decantation. Dorr system, 117 Cracks in filter cake, 108 Crawford, P. H., aluminium precipi- tation, 195 Creston Colorada, experiments on relative efficiency of sodium and potassium cyanides, 16 Critical point in addition of lead compounds to pulp, 14, 227 Crosse, A. F., process of cyanide re- generation, 7 Crowe vacuum process in zinc pre- cipitation, 174, 177 Crucible-melting of precipitate, 204 Crucible reverberatory furnace, 204 Cupellation of lead bullion in Home- stake practice, 212 Cupellation of lead bullion in the Tavener process, 211 Current density in electrolytic pre- cipitation, 186 " '' Minas Prietas electrolytic practice, 187 ", efficiency in electrolytic precipitation, 188 Cyanate determination, 41 formed by oxidation of cy- anide solutions, 11 u (( II it Cyanates, produced by oxidizing agents, 4 Cyanidation of concentrate, 169 " " flotation concen- trate, 172 Cyanide consumption, by base met- als, 12 " mechan- i c a 1 loss, 10 computation in labora- tory tests, 222 " " excessive, in labora- tory tests, 229 " '' " in cyani- dation of concentrate, 170 Cyanide consumption, in laboratory tests due to silver, 224 Cyanide consumption, in treating silver ores, 10 Cyanide consumption, in zinc pre- cipitation, 10 Cyanide (free), determination, 20 loss in residues, 12, 223 method of copper* determin- ation, 34 poisoning, antidote, 238 "total," determination, 24 traces, in water, detection of, 25 solution, effect on amalga- mation, 123 strength in slime treat- ment, 98 D Data of cyanide tanks in various plants, 231 n (< II tl i( << II 262 INDEX Data of slime filters in various plants (Table), 232 Dajrton, Nevada, practice in pre- cipitation of coppery solutions, 179 Deoantation process of slime treat- ment, 107 " " conducive to loss of cya- nide, 10 Decomposition of cyanide solution, 10 Deep leaching tanks versus shallow ones, 69 Definition of slime, 73 Dehne filter press, 107 Denny, J. J., desulphurizing arsenic- and antimony-silver ores, 166 Denny, J. J., desulphurizing precipi- tated silver sulphide, 199 Density determination of slime pulp, 132 Depth of sand charge, 69 Devereux agitator, 96 Diamond dye, in estimating oxygen in working solutions, 51 Diaphragm cone, the Caldecott, 61, 63 " I)orous, used in electro- lytic precipitation, 189 Diehl, Dr., bromocyanide treatment, 157 Dilution of pulp in slime treatment, 98 Disc filter, 115 Discharging of sand residue, 72 Discrepancy between recovery and theoretical extraction, 126 Dissolving effect of zinc potassium cyanide, 5 efficiency of sodium and potassium cyanides, 15 ii Distributor, Butters and Mein, 55, • 61, 62 Divisadero Mill special filter leaf, 111, 198 Dorr, J. V. N., classifier, 64 Dorr continuous counter- current de- cantation, 117 Dorr continuous counteivcurrent de- cantation in aluminium precipita- tion, 198 Dorr slime agitator, 93 " thickener, 79 *' thickeners, operation of, 86 ^' washing classifier, 66 Double filtering, 124 "Double salt" potassium cyanide, 15, 17 Double treatment for sand, 60 Dowsett, C. W., colorimetric detec- tion of gold in cyanide solutions, 53 Draining dry between washes, 68 Dressing the zinc boxes, 181 Dropping the cakes in the Butters filter, 108 Drucker, A. E., reduction of matte, 210 Dry ore, specific gravity determina- tion, 132 Drying of samples before cyanida- tion to be avoided, 214, 216 " " zinc precipitate for melt- ing, 204 Dry-screening in laboratory tests, 220 Durant, H. T., aeration of dam- slime, 89 " " " modification in elec- trolytic precipita- tion, 186 Dyscrasite, in Nipissing silver ores, 166, 168 INDEX 263 E Ekimands, H. R., method of charcoal dust precipitation, 199 Efficiency of a cyanide solution pro- portional to free cy- anide as determined without KI indica- tor, 6 " " slime filters in alu- minium precipitation, 198 El Oro, Mexico, air-lift for leaching tanks, 68 Electrolysis of solutions in acid treat- ment of manganese-silver ores, 165 Electrolytes in slime settlement, 76 Electroljrtic precipitation, 185 " " for deaUng with coppery s o lu - tio ns, 179 Eisner's equation, 1 Error in density determination due to specific gravity of the solution, 140 Evaporation in laboratory bottle tests, 217 '^ of solution in leaching tests, 226 Excess of bulUon over calculated amount, 127, 156 Experiments, 213 Extraction determination in labora- tory tests, 224 Extractor, Moore-Edmands, for charcoal precipitation, 200 Feldtmann, W. <{ i( Gold, assay of solutions for, 52 in aluminium precipitation, 197 K Gold, in cyanide solutions, colori- metric detection of, 53 ores, low grade, and zinc dust precipitation, 184 reaction with cyanide solu- tion, 1 Graphite, in cyanidation of gold ores, 162 Graphitic ores, causing premature precipitation, 15 Gravity percolation in leaching, 67 Green, Leonard M., titration for protective alkali, 29 Grinding in the laboratory com- pared with mill work, 222 laboratory samples in tube miU, 13 of samples, wet, 214 sampled to a given screen size, 222 tests for necessary fineness, 218 H Hahn, A. W., experiments in elec- trolytic precipitation, 189 Haloid silver compounds, reaction with cyanide solution, 1 Hamilton, E. M., process of alumin- ium precipita- tion, 194 " " ** sand collecting tank, 59 Harvey, A., guide to size of crushing in sampling ore (Table), 152 Head ore, value calculated by differ- ence, 152 samples, importance of fine crushing, 150 when milling in solu- tion, 148, 155 t( tt t( t( it (< tt INDEX 265 (< (( II u ii n (t it <( << tf It Heating of solutions, effect on rate o f dissolu- tion of gold, 5 for precipita- tion, 179 in cold cli- •mates, 5 in Crosse's re- generation process, 7 resulting in de- composition of cyanide, 10 Hendryx agitator, 95 Higgins, practice in precipitating coppery solutions, 179 High alkalinity, as a cyanide saver, 6 " cyanide consumption in lab- oratory tests, 229 Higham dividing box, for use with automatic pulp sampler, 148 " James, automatic pulp sam- pler, 146 Hills, L. A., use of manganese dioxide in melting precipitate, 206 Julian, H. F., aluminium precipita- tion, 189 Julian, H. F., and Smart, K, action of bromocyanide, 4 Julian, H. F., and Smart, E., action of weak solutions, 9 Julian, H. F., and Smart, E., bromo- cyanide treatment, 157 Julian, H. F., and Smart, E., depolar- izing action of oxygen, 3 Julian, H. F., and Smart, E., dilution of pulp in slime treatment, 98 Julian, H. F., and Smart, E., effect of copper on eflficiency of cyanide solutions, 8 Julian, H. F., and Smart, E., effect of temperature on rate of dissolution of gold, 5 Julian, H. F., and Smart, E., flux for precipitate, 206 Julian, H. F., and Smart, E., forma- tion of acetates in cyanide solu- tions, 45 Julian, H. F., and Smart, E., percola- tion of sand, 69 Julian, H. F., and Smart, E. ,reaction in zinc precipitation, 174 Julian, H. F., and Smart, E., reaction of copper with cyanide solutions, 12 Julian, H. F., and Smart, E., washing out the dissolved metals in leach- ing treatment, 71 Julian, H. F., and Smart, E., zinc- lead couple, 178 K Kalgurli, air-lift for leaching tanks, 68 " practice for telluride ores, 157 Kelly filter, 116 Kirkpatrick, S. F., aluminium pre- cipitation, 189 Kline, R. C, increased extraction due to presence of potassium base, 18 " " " treatment of silver matte, 210 It it ti it it a Laboratory experiments, 213 Large scale agitation tests, 229 '' '* sand leaching tests, 226 Layng, H. R., dissolving silver sul- phide in cyanide solution, 3 Leaching of fine sand, 60, 74 " raw concentrate, 169 '^ sand, 55 tank construction, 66 tests, 224 " on sand by agitation method, 219 " preparation for, of easily oxidized ores, 225 treatment procedure, 66 Lead compounds, as a prevention of sulphocyanate formation, 14 as aid to extrac- tion of silver ores, 14 effect on efficiency of cyanide solu- tions, 8 in laboratory tests, 227 (( tt tt n INDEX 267 it It Lead compounds, use of, prejudicial with antimony- and arsenic-sil- vfer ores, 192 peroxidized, as anodes, 187 sulphide, reaction with cyanide solutions, 14 Leaf, special, for Butters filters, to obviate acid treatment, 112, 198 Leaver, E. S., amalgamation in cy- anide solution, 123 Leslie, H. M., experiments on loss of cyanide as HCN, 11 Lime, a regenerator of cyanide from double zinc salt, 6, 224 addition in milling, 76 amount added in milling, 77 available alkalinity of, 29, 218 carbonate on leaching tank filter cloth, 70 consumption tests, 218 elimination by soda ash in aluminium precipitation, 195 in aluminium precipitation, 191 '* reaction with solutions from zinc precipitation, 175 lime-water in amalgamation, 77 Litharge, a substitute for lead ace- tate in treating silver ores, 14 in the Home&take melting practice, 211 " " Tavener melting process, 210 Loss of cyanide in residues, 10, 223 Lowering vacuum to prevent forma- tion of cracks in filter cake, 108 M MacArthur, J. S., zinc-lead  Bernard, the Parral tank, 96 Manganese-silver ores, 163 Marcasite, a source of ferrocyanide formation, 13 Matte, reduction of, 210 Mechanical agitator for slime pulp, 89 ** classifiers, 63 in direct treatment of sand, 65 Melting gold precipitate from char- coal precipitation, 201 " the precipitate, 204 Merrill, C. W., cones, 60 sand collection, 60 slime press, 105 triangular precipita- tion press, 184 zinc dust precipita- tion, 183 Metallic gold and silver in labora- tory experiments, 213 Metals and their minerals (Table), 250 Methyl orange, as indicator in pro- tective alkali determination, 11 Metric weights and measures, 245 Mexican reverberatory melting prac- tice, 205 Middling in concentration, elimina- tion by calculation, 249 Mill head sampling, 146 Milling in cyanide solution, 123 ** solution, sampling of head, 148, 155 " water, 77 Minas Prietas practice in electro- lytic precipitation, 186 Minerals, and their characteristic^ (Tables), 250 Mispickel gold ores, treatment of, 4, 157 (( (( 268 INDEX ti it Mixing the fluxes for melting pre- cipitate, 208 Moisture determination as a substi- tute for specific gravity of slime pulp, 141 estimation in mill ore, 130 retained in sand charge, 69 Moldenhauer, aluminium precipita- tion, 189 Moore, vacuum filter, 112 N Nardin, E. W., detaib of bromocya- nide treatment at Hannan's Star MiU, 158 Neal, Walter, flux for silver precipi- tate, 207 " *' treatment of mangan- ese-silver ores, 166 Neutral solutions for treating anti- monial gold ores, 162 '* Nigger and hose" system of slime separation, 57 Nipissing mill melting practice, 205 practice, aluminium pre- cipitation, 190 " in sodium sul- phide precipi- tation, 199 reduction costs, 235 silver ores, treatment of, 166 Nitre, in melting precipitate, 206 Nitric acid, decinormal solution, 26 Nutter, E. H., amalgamation in cyanide solution, 123 II ti (t ti O OUver vacuum filter, 112 Ore,  5 Over-grinding of samples, 222 m tube mUl,214 Oxalic acid, decinormal solution, 26 for titration of protective alkali, 26 standard solutions, 28 table of varying strength and factors, 29 Oxidation, as a remedy for fouling of solutions, 8 ** an aid to treatment of antimonial gold ores, 162 of cyanide solutions, 11 " soluble sulphides, 1 '^ zinc during the clean- up, 182 Oxidizing agents as aids to the dis- solution of gold and silver, 3 " in melting precipi- tate, 206 roast detrimental to silver ores, 164 " of silver concentrate detrimental to cy- anide treatment, 169 Oxygen, action of, in zinc precipita- tion, 176 as a depolarizing agent, 3 dissolved in distilled water, 50 estimation of, in working cyanide solutions, 48, 176 function in dissolving gold and silver, 3 rapidly absorbed by current  a source of cy- anide loss, 11 cyanide strengths used, 9, 98 practice in zinc dust pre- cipitation, 174, 185 slime agitator, 91 tanks, dilution of pulp, 99 " in the laboratory, 217 Paper bags for charging crucibles, 208 Park, James, action of copper in zinc precipitation, 179 " ^* charcoal precipitation, 199 definition of slime, 73 fluxes for precipitate, 206 process of slime treat- ment, 106 reactions in zinc pre- cipitation, 174 Parral agitator tank, 96 Percolation rate, 69 Percolator for leaching tests, 225 Permanganate, as an oxidizing agent, 3 decinormal solution, 38 estimation of reduc- ing agents, 4 to check action of cyanide in pulp samples, 154 Peroxide of sodium, as an oxidizing agent, 3 Peroxidized lead anodes, 187 Phenolphthalein, as indicator in pro- tective alkali determination, 11, 27 Piping for leaching tanks, 67 u II u II (( a u It it II it ft (( (t Plant data, cyanide tanks, 231 Poisoning by cyanide, antidote, 238 Potassium and sodium cyanides, rel- ative dissolving effi- ciency, 15 cyanide, as the standard for titration, 19 ferricyanide, as an oxi- dizing agent, 3 iodide, indicator in cy- anide titration, 21, 23, 24 permanganate, as an oxi- dizing agent, 3 " decinor- m a 1 solu- tion, 38 salts, conducive to in- creasing extraction, 18 Pouring crucibles, 209 Power data, 249 Precious metals as a source of cy- anide consumption, 9 Precipitate obtained from alumin- ium precipitation, 197 Precipitating action of antimony and pyrrhotite in cyanidation of gold ores, 162 Precipitation by zinc, a source of cy- anide loss, 10 of the gold and silver, 173 premature, 14 Preparation of precipitate charge for melting, 2f»8 Press for zinc dust precipitation, 184 Pressure data, 249 Protective alkali, definition of, 26 ** determination. 26 It It (I a V 270 INDEX Prussian blue, formed in Siemens- 9alske precipita- tion, 186 " "in sulphocyanate de- termination, 40 Pulp sampler, automatic, 146 Pyrite, a source of f errocyanide for- mation, 13 Pyrogallic acid, use in estimating oxygen in working solutions, 48 Pyirhotite, in cyanidation of gold ores, 162 Q Quantity of solution in leaching treatment, 70 R Rand, experiments on loss of cy- anide as HCN, 11 institution of double treat- ment for sand, 60 practice in slime treatment, 107 strength of solution in slime treatment, 98 Rate of percolation, 69 Ratio of aluminium to silver in aluminium precipita- tion, 190 " solution to ore in leaching treatment, 70 " zinc to silver in zinc pre- cipitation, 174 Reactions in zinc precipitation, 174 Recovery, discrepancy with theoret- ical extraction, 126 ** in concentration, formu- las, 248 Reducing action of  dams, 5 power, estimation of, 4 treatment an aid in cyan- iding refractory man- ganese-silver ores, 164 Reduction costs for various mills (Tables), 233 method of determining iron, 38 of slime filter efficiency in aluminium precipita- tion, 198 Refining silver bullion at Nipissing, 205 Regeneration of cyanide by acid treatment, 8 Regeneration of cyanide by Crosse's process, 7 Regeneration of cyanide from the double zinc salt, 6, 224 Regeneration of cyanide from zinc cyanide solutions, 10 Regeneration of cyanide in alumin- ium precipitation, 171, 190, 197 Regeneration of cyanide in electro- lytic precipitation, 188 Regeneration of cyanide in sodium sulphide precipitation, 171, 199 Relative dissolving efficiency of so- dium and potassium cyanides, 15 Repeated use of solutions, labora- tory test, 227 Residue, loss of cyanide in, 10, 223 sampling, 152 sand, discharging, 72 Retained moisture in sand charge, 69 Reverberatory for bulk melting of precipitate, 205 melting,  gold ores, 157 *^ of gold concentrate, 169 Roscoe & Lunt, table showing oxy- gen dissolved in distilled water, 49 S Sampler for pulp, automatic, 146 Sampling bullion bars, 209 by hand, mill heads, 149 of mill heads, 146 " " " when mill- ing in so- lu t ion, 123, 148, 155 " " residues, 152 plant, for mill heads, 148 pulp at different stages of treatment, 153 Sand filter for clarification of solu- tions, 173 ** in "all-sliming" product, 74 " melting precipitate, 205 leaching, 55 " strength of solutions, 9 " " tests, large scale, 226 residues, discharging, 72 " sampling, 152 tonnage, computation by meas- urement, 128, 131 Santa Gertrudis experiments in elec- trolytic precipitation, 189 Saving by aluminium precipitation, 197 Screen sizing, in water, 220 "  215 Selective action of weak solution, 8 " agitation in the Dorr tank, 95 Separation of sand and slime, 55 by dry screening, 225 by washing in the laboratory, 225 Settlement of slime, 76 Sharwood, W. J., estimation of sul- phocyanate, 40 " " on copper deter- mination, 34 " " " solubiUty of sil- ver in pres- ence of po- tassium sul- phide, 2 Short zinc, 182, 203, 207, 211 Shortage of bullion in clean-up, 126 Short-circuiting of pulp in continu- ous agitation, 100 Siemens- Halske electrolytic precipi- tation, 178, 185 Sieves, I. M. M. London standard, 240 " Tyler Standard, 238 Silver, a source of cyanide consump- tion in cyanidation of con- centrate, 171 as a source of cyanide con- sumption, 9 assay of solutions for, 52 chloride, reaction with cy- anide solution, 1 determination, Volhard's method, 44 in charcoal precipitation, 200 " cyanide solutions, colon- metric estimation of, 54  u ic Silver, nitrate, decinormal solution, 44 " " standard solution, 20 standard solution, table of varying strengths and fac- tors, 25 ores containing arsenic and antimony, 166 " fine grinding of, 75 sulphide, causing formation of sulphocyanate, 13 " " not acted on by zinc-potassium cyanide, 5 precipitate, reduc- tion by Denny's process, 199 precipitated from cyanide solution by diluting with water, 2 reaction with cyanide solutions, 1,2,9 Silver sulphide, reaction with lead salts, 14 Silver sulphide, solubility in cy- anide solution in presence of sodium sulphide, 2 sulphocyanate, 3 Silver-manganese ores, 163 Sizing tests, 219 Slag, disposal of, 209 Slime, coagulation of, 76 " definition of, 73 filters in various plants (Table), 232 in laboratory tests estimated by panning, 220 residue, loss of cyanide in, 10 sampling, 153 a << ti ii ii It ({ II (( tt it n <( (( II Slime, retarding action in percola- tion of sand, 69 separation from sand, 55 " in the laboratory by washing, 225 settlement, 76, 80 spitzkasten, 77 the extraction treatment, 88 " thickening tank, 79 tonnage estimation by specific gravity, 131 treatment in filter presses, 102 *' strength of solu- tions, 9 Sluicing out sand residues, 72 Snifter valve, for aeration in slime treatment, 89 Soda ash, use in aluminium precipi- tation, 195 ** caustic, formed in Crosse's cy- anide regeneration process, 7 Sodium aluminate, 191 cyanide, 16 peroxide, as an oxidizing agent, 3 and potassium cyanides, rel- ative dissolving efficiency, 15 (potassium) sulphate, formed by oxidation of sodium sulphide, 1 sulphide, as precipitant in cyanidation of silver con- centrate, 171 (potassium) sulphide, formed in dissolving silver sulphide, 1 sulphide, in Crosse's cy- anide regenera- tion process, 7 method of precipi- tation, 199 n it ii it ii ti it  anide with silver sulphide, 1 thiosulphate, decinormal solution, 31 (p ot assiu m ) thiosulphate, formed by oxidation of sodium sulphide, 1 Soluble sulphides, as harmful reduc- ing agents, 5 estimation of, 46 in aluminium pre- cipitation, 192 present simultane- ously with sil- ver in cyanide solution, 2 reaction with lead salts, 14 Soluble sulphides, reaction with solu- tions from zinc precipitation, 175 Soluble sulphides, regenerating effect on zinc cyanide solutions, 6 Solution, application to leaching tanks, 67 ratio * in leaching treat- ment, 70 strength in cyanide, 8, 9 " '* leaching treat- ment, 70 Sources of apparent shortage of bul- lion, 128 " " cyanide consumption, 9 Special filter leaf for Butters filter, 111, 198 Specific gravity of dry ore, deter- mination, 132 " " solution, a source of error in slime densitv determination, 140 18 tl If tt tt specific gravity of wet pulp, deter- mination, 133 " " to estimate tonnage of slime pulp, 128, 131 Spitzkasten for slime, 77 Stages of treatment, sampling of pulp, 153 Standard solutions of oxalic acid, 28 Standard solutions of oxalic acid, table of varying strengths and factors, 29 Standard solutions of silver nitrate, 20 Standard solutions of silver nitrate, table of varying strengths and factors, 25 Standardization of decinormal per- manganate, 39 " " sodium sulphide solution, 47 Steel precipitation boxes, reaction with caustic soda in solutions, 181 Strength of cyanide in slime treat- ment, 98 ^* solution in cyanide, 8, 9 "leaching treatment, 70 Strong solution, making up for the leaching treatment, 70 Succession of washes, for increasing the dissolving effect, 99, 121 Sulman, H. L. & Picard, H. K., zinc dust precipitation, 183 Sulphantimonide silver ore, 166 Sulpharsenide silver ore, 166 Sulphates of iron, in the cyanidation of concentrate, 170 " sodium formed by oxi- dation of sodium sul- phide, 1 tt tt tt 274 INDEX it It tt ti it tt it tt tt tt Sulphide of silver, not acted on by- zinc potassium cyanide, 6 " " reaction with cy- anide solu- tion, 1 sodium, in aluminium pre- cipitation, 192 in Crosse's cyanide regeneration process, 7 method of precipi- tation, 199 Sulphides, soluble, as harmful reduc- ing agents, 5 estimation of, 46 formed in dis- solving silver sulphide, 1 Sulphocyanate, a source of cyanide consumption, 13 decinormal solution, 44 determination, 39 formed by reaction of cyanide with silver sulphide, 1, 13 from lead sulphide, 14 in the treat- ment of silver ores, 9 in aluminium pre- cipitation, 192 method of estimat- ing iron, 37 not a detrimental reducing agent, 4 of silver, 3 it ti ft it ft ti ti it tt it u tl tt Sulphuretted hydrogen, as a harmful reducing agent, 5 in d a m - slimes, 89 used in Crosse's cyanide regenera- tion proc- ess, 7 Sulphuric acid treatment in the cy- anidation of concentrate, 170 Sulphurous acid, as a harmful reduc- ing agent, 5 " determination, 166 " treatment of man- ganese-silver ores, 166 Sutton (Vol. Anal.), saturating dis- tilled water with oxygen, 49 Sweetland filter, 116 it it it Tank capacities, formula, 248 Tavener, P. S., process of melting precipitate, 210 Telluride gold ores, 157 " " treatment of, 4 Temperature of solutions, effect on rate of dissolution of gold, 5 Thermometer conversion table, 242 Thickener, the Dorr, 79 Thickening of slime pulp, 77, 80 Thiosulphate, as a harmful reducing ing agent, 5 for titration of bromo- cyanide, 158 formed by oxidation of sodium sulphide, 1 it ti INDEX 275 Thiosulphate, in aluminium precipi- tation, 192 of soda, decinormal solution, 31 ** solution, standardiza- tion with copper sulphate, 159 Time of agitation in slime treatment, 99 Tin plate, as cathodes, 187 Tonnage computation, 127, 130 Tonopah Belmont, reduction costs, 234 Tonopah practice, in heating of solu- tions, 5 "Total" cyanide determination, 24 Traces of cyanide in water, detection of, 25 Trent agitator, 95 Tube mill for laboratory samples, 214 " " grinding of laboratory samples, 13 Tyler standard sieves, 219, 238 U Upward percolation in leaching, 67 Vacuum application in sand leach- ing, 70 " filter for sand, the Calde- cott, 62 filters, 107 use in sand leaching tests, 226 Vent for air entrapped in leaching tanks, 67 Virgoe, Walter, elimination of zinc in solutions from zinc precipitation, 176 Virgoe, Walter, method of solution assay, 52 " " titration of cyanide solutions contain- ing copper, 23 Volatilization in chloridizing roast- ing, 164 Volhard's silver determination, 44 Volume of solution, ratio to alumin- ium in aluminium precipitation, 191 W Waihi Grand Junction, reduction costs, 234 Washes, a succession of, for increas- ing the dissolving effect, 99, 121 Washing out the dissolved metals after slime treatment, 106 Washing out the dissolved metals in the leaching treatment, 71 Water, addition of, to stock solu- tion, 124 to replace solution in zinc box clean-up, 202, 203 wash, effect in increasing ap- parent dissolving action in pulp, 121 Weak solutions, precipitation of, 178 " ** selective action, 8 Weights and measures, conversion tables, 246 English and American, 244 metric sys- tem, ?45 Wet-grinding of samples, 214 on buck- it t( (< u tl »< tt ft (( tl (t u ing table, 215 Wet pulp, speicific gravity determina- tion, 133 276 INDEX t( it tt Wheeler, Roscoe, data on the Dever- eux agitator, 96 Whitby, A., assay of slime pulp con- taining soluble gold, 155 White end-point in titration for free cyanide, 22 White, H. 