The deposits of the useful minerals & rocks; their origin, form, and content . con-sequences of such colossal pressureas must be postulated, would havebeen e^ident first of all upon thecountry-rock directly in touch withthe quartz. Carbonates of lime, mag-nesia, and iron are some-times mixed with the quartz,being often found along thewalls. Chlorite in small bent,though definite crystals canalso at times be observed. The sulphides are limitedalmost exclusively to pyritearsenopyrite with a smallamount of galena, these mineralsoccurring particularly in the slatedirectly adjacent to the quartz ;c
The deposits of the useful minerals & rocks; their origin, form, and content . con-sequences of such colossal pressureas must be postulated, would havebeen e^ident first of all upon thecountry-rock directly in touch withthe quartz. Carbonates of lime, mag-nesia, and iron are some-times mixed with the quartz,being often found along thewalls. Chlorite in small bent,though definite crystals canalso at times be observed. The sulphides are limitedalmost exclusively to pyritearsenopyrite with a smallamount of galena, these mineralsoccurring particularly in the slatedirectly adjacent to the quartz ;crystals of pyrite indeed are notinfrequently found embedded one-half in quartz and the other halfin black slate. Lindgren, whose descriptionis here chiefly followed, found albite in theauriferous quartz of the South New Moon, oneof the most productive mines around EagleHawk. In that mine the ore does not occurin a saddle lode but in the form of a spuror irregular quartz mass in the black slate. 314.—Map showing the goldfields of South W^ales, and and THE OLD GOLD LODES 613 \i68iL€vel I^ :^J770levei The gold in general is coarse-grained, and in massive, white, almostglassy quartz, may often be observed in large pieces. With regard to the maintenance of gold content in depth, many of themines are already more than 1000 m. deep ; indeed the New Chum Rail-way mine in the year 1906 cut an apparently still payable saddle lode ata depth of almost 1400 metres. The limit of payability is put at 7 dwt., orabout 10 grm. of gold per ton. Generally speaking, experience has shownthat the ore above 2500 feet was considerably richer /^--yyi^^-,--^^^- /^ V ^\ \\\.than that obtained below /?0:&--^^-:./%^^^<^that depth. ^^M-^^f^ • -« • Up to 1906 the district -^^^had altogether producedapproximately 20-5 millionoz. of gold, of which 6millions were derived ex-clusively from primary ore,while the remaining 14-5millions came partly fromprimary ore and partly fro
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectminesandmineralresou
