The Arizona sentinel., 1901-11-27
LA FORTuNA MINE.

In the early days of gold discovery of Califor- nia, ls4S, when the news reached the gold miners of Sonora, there was q general exodus Of the dble-bodied men who were able to get away northwest to the new Fl Dorado in California and the state of Sonora contributed many me-. to the mining population. They took the oiO road, which was known as the ''camino real, ' from EStancia and Altar nOrthweStward, nearly parallel to the gulf following the mountail ridge known as the Gila range, just north of oui present boundary. The road led to Yuma. ans in passing tue Gila range they went within [ few feet or yards of very modest outcTop oi quartz which no one seemed to consider of sui 6cient value to merit any attention. That hum ble and insignificant quartz outcrop is today the outcrop of the great Fortuna mine
 It is situated on the westward slope and nearl7 at the base of the range of mountains called on some of the old maps the Gila range. This trends northwesterly and reaches nearly to the Gila river at the point now known as Blaisdell The railway in it's course to Yuma passes around the northwest point of this range Where the rocks are exposed at that point they are mostly of homogeneous granite of gray col0T and weathered out at the surfaces which however, are much pitted as if by decomposi- tion of some soft substance. But beyond these lOw-lying hfI1s of granite there are big outcropS of rock which to the experienced eve indicate Stratit1ed formations. They are indeed strait lied, for the bulk of the range southward and southeastward is composed of regular stratificd laminated, hard gneiSSic rock. use the word ''gneissic in very general and comprehensive sense, for you can describe these rocks with
 
 mica states and hornblendc states, with inter polationS of quartZite beds. especially in the upper part of the series. with green stains sup posed to be stains of copper and decomposition Of copper ore, which they probably are al though there are peculiarities of color, and some yellow colors, which indicate to me the lurium, which by its decomposition has given these colorS. The fact remains, however, that the bullion from the upper part of the vein con- ta1ns more copper than 1t now contains in the n min ,t, have been carried on here have developed a condition of things which could not be foretcld from an inspection of the outcrop. The vein or lode appears to be a chimney, not Q contino- GUS ore body, nor a continuous vein with an ore body or chimney or chute upon it. As re- marked the outcropping points indicate that tnere is no very great longitudinal extension of this ore body.
 The vein is remarkable first in this limited out crop; second, in it's continuity in depth its con- gives of enrichment by further veins dipping into 1t on the foot-wal sides.
 Some facts in regard to the product or yield: The ore paid from the surface. The product or orc extracted up to the time has been about 80 tons per day, which is sent to the 20Stamp mill, each stamp of which cruShes about tons in every twenty-four hours. The extraction is chiefly and largely by power drills. force of 80 men is employed by this mine and mill. The greater part of the labor underground and mining IS done by compressed air. The lode, was told, was to l5 feet wide This large space permits the use of power drills to great advantage. In the material hoiSted there are fragments of the wall rocks, some of which are thrown out, but many pieces pass through the r1ill. They would prefer to reject most of this wall rock. but it would take more time and ex. penSe than 1t does to mill it, and there is a chance of some of it containing gold. From these So tons of rock crushed daily the average product is perhaps SIS 900 worth of gold peI month. Some months they have produced as high as Se0,0O0.
 In the region of the Fortuna mine the forma tions appear to be wholly of mica slate and hornblende slate, with some aren1ceouS layers Ike old micaceous SandStones and quarIzites The mine is surrounded by black hornblendiI ElateS and mica SlateS. dipping Southwafd ana southweStward al an angle Of about 45 degrees and these slates are very evenly laninated ridge after ridge.