Ana was found to increase in richness as it increased in depth, and Rāyăs having obtained exclusive possession of it, the shaft of Santa Rosa was sunk, through which the first great Bonanza was obtained.
This rich mass of ores (clavo rico) being exhausted, new workings were tried in a S.E. direction, and the shaft of San Miguel was sunk by the father of the present proprietor, at an expence of 700,000 dollars: through this the family of Sardaneta obtained a second Bonanza, which lasted several years, and produced a net profit of eleven millions of dollars, clear of all expences.
From 1760 till 1780 the Mine continued to be worked with considerable profit; but in that year an accident occurred, which very nearly caused it to be entirely given up. A torrent, formed suddenly in the mountains, took its course down the Cañada of Rayas, and entered the mouth of the mine, which had no protection against so unforeseen a danger, filling in a moment the lower levels, and destroying almost all the workmen employed at the time. So great was the volume of water admitted, that nineteen years were consumed in the drainage, which was not completed till 1799, when the mine was again rendered productive, and yielded, in each of the four succeeding years, a clear profit of 400,000 dollars. Since then, the greatest part of the produce has been absorbed by the construction of the new Tiro General, commenced by the pre-
