. Mining and Scientific Press . hypothesis for the deposition of the ore is basedon the theory thai the granite shattered the adjacent•• and formed the north-south fractures that havenow become the silver-bearing veins. The subsequentintrusion of the silicious dike re-opened these fracturesand probably introduced the silver-bearing fissured area near the schist granite contact was par-ticularly receptive nol onlj because of its physical con-dition, but perhaps because of its chemical characteristics; takes an easterly course through Uranium No. 2 and No 1 shaft was started
. Mining and Scientific Press . hypothesis for the deposition of the ore is basedon the theory thai the granite shattered the adjacent•• and formed the north-south fractures that havenow become the silver-bearing veins. The subsequentintrusion of the silicious dike re-opened these fracturesand probably introduced the silver-bearing fissured area near the schist granite contact was par-ticularly receptive nol onlj because of its physical con-dition, but perhaps because of its chemical characteristics; takes an easterly course through Uranium No. 2 and No 1 shaft was started at the discovery-point andfollowed a wide lode, with a will defined foot-wall, com-monly known as the shaft fracture. A drift on the? •I of this fracture has I een followed for a totaldist! ace of 510 ft., including sonic work from the mentioned above. The ore at the surface was oxidized, with flakes andbunches of hornsilver. A peculiarity was the alterua- ^ Johannesburg ; scALt or rccrpoo a ooo RaYidsburg. FlG. 1. CLAIM-MAP OP THE RANDSBURG DISTRICT thai is. the minerals deposited at the time of the intrusionranite may later have reacted chemically to stim-ulate the precipitation of the minerals that formed theore. At any rate the silicious dike seems tothe dividing line between the gold and the silver zonesriot, even thougk it may develop that some? intrusion, which subsequently may be hing solutions. Tl ?. on a line that represents the prolongation of the Juanita contact-vein. The vein itself cannot, be traced beyond the dike, although the contact swings and tion of thin layers of hard and soft material, the softbeing far richer than the hard. These layers dipped onlyfrom 5° to 15°, to the east, and. as progress was made insinking, there was constant speculation as to whethereacli successive lean layer would be underlain by a richone. The pessimists were sure that the deposit was onlya freak, and that after a
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