Identifier: californiaminesm00cali (find matches)
Title: California mines and minerals
Year: 1899 (1890s)
Authors: California Mining Association Benjamin, Edward H
Subjects: Mines and mineral resources -- California
Publisher: San Francisco : (Press of Louis Roesch Co.)
Contributing Library: University of Connecticut Libraries
Digitizing Sponsor: University of Connecticut Libraries

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al-ized sections of the lode the ribbon rock contains the better values —the slaty seams being rich. It occurs as well, however, in poorlymineralized sections, where it contains little value, of course. Quartz often extends from the vein irregularly into more or lessshattered portions of the wall rocks — in large part by substi-tution, it is believed. This quartz occasionally carries sufficient valu-able mineral with it to form considerable bodies of profitable ore,usually low-grade, however. In some sections of the lode there are extensive bodies of mineral-ized talcose slates, directly associated with one of the main fissures.These sometimes contain several dollars per ton in fine gold and havebeen mined to some extent near to the surface. The hanging-wall slates, near to the surface, are in places fissuredand traversed by a great number of small seams of quartz, carryingcoarse gold. Many such bodies have been mined by open-cut work,but peter out or become unprofitable in depth.
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THE MOTHER LODE 63 At the northerly end of El Dorado county, where the Mother Lodebelt divides and apparently scatters, there are a number of so-calledseam diggings — occurrences somewhat similar to the above, butnot directly connected with a large fissure, at least not apparently.These are belts of soft, finely laminated slate, somewhat talcose,seamed with innumerable veinlets and stringers of quartz, and con-taining considerable coarse gold. Most of the seams cut the laminseat very acute angles, while others are nearly at right angles. Thesebelts are 100 or 200 feet wide and have been mined to a considerableextent by open-cut work, especially at the Georgia slide and SpanishDry Diggings. The average thickness of the underground ore bodies, so far minedin the lode proper, has been probably five or six feet, varying fromone to fifty or more. The average yield has been about $10 per ton,varying from $3 to $25. But it must be borne in mind that thegreater part of the ore has been extr

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