North Bay Resources Inc (NBRI)

[orefinder]

Ruby Gold Mine in THE TERTIARY GRAVELS OF THE SIERRA NEVADA OF CALIFORNIA by W. Lindgren, 1911

The productiveness of a channel is best measured by its yield per linear foot. The Ruby Gravel Mine, in Sierra County, in which the channel was from 50 to 300 feet in width, was worked for a distance of 3,850 feet and yielded at the rate of $465 a linear foot. The cost is stated to have averaged $240 a foot.

The gold content of the gravel varies, of course, enormously. In general it may be said that the upper gravels, sands, and clays are very poor; and although more gold is contained in the lower gravels it is only within a few feet of the bedrock that the rich material begins to appear. By far the greatest part of the gold is ordinarily contained in the gravel within 3 feet of the bedrock, and in many places within the last foot above the bedrock.

http://pubs.er.usgs.gov/publication/pp73

It was FEASIBLE back then to mine gold at $18.92 per ounce with antiquated technology and lower productivity so it will be definitely FEASIBLE to mine gold (at $1,250 per ounce) in 2015 with our new technology.