The Arizona sentinel., 1901-07-03
LA FORTUNA MINE.

In the early days of gold discovery of Califor- mia. lS4S, when the news reached the gold miners of Sonora there d general exodus of the able bodied men who were able to get away northwest to the new El Dorado in California. and the state of Sonora contributed many men tu tllc mining populaCioh. They took the old road, which Was known as the ''camino real, ." from ESlanc1a and Altar orthWeStward, nearly parallel to the gulf. following the mountain ridge known as the GiIa range. just north of our present. boundary. The read led to Yuma, and in passing the Gi!a range they went within q few feet or yards of a very modest outcrop of quartz which TO one seemed to consider of sui hcienJ value to merit any attention. That hum bic and insignificant quartz Outcrop S today the Outcrop of tn" great Fortuna mine.
 l. S situated on the weStwar1 slope and nearly at the base of the range Of mountains called un some ot the old maps the Giia range. This trends nOrthEeSterly and reaches nearly to the Gia river at the point now known aS BiaiSden The railway in it's course to Yuma passes around the northwest point of this range. Where the rocks arc exposed at that point they arc mostly of homogeneous granite, of gray color and wcathered out at the surfaces, which, however, are much pitted as if hy dccOmpoSi- tion of some soft substance. But beyond these lOy-lying hills of granite there are biz OutcropS of rock which to the experienced eye indicate stratiticd formations. They are indeed strait fled. for the bulk Of the range Southward and SoutheIStward is composed of regular Stratified laminated, hard gneiSSic rock. use the word 'gneiSSic in q very general and comprehensive sense, for you can describe these rocks with mncn more accuracy IT you iOcallZc them 2S mica states and hornbiendic states, with inter- polationS Of quartZitc beds. especially in the upper part of the series, with green stains SUD- 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 70 me the presence of some other mineral. possibly tel lurium, which by it's decomposition has given these colorS. The fact remains however that the bullion from the upper part of the vein con- tainS more copper than it now contains in the lower levels of the mine. The workings which have been carried OF here have dcycIOUcd a condition of things which could not be foretod from m inspection Of the outcrOp. The vein or lode appears to be q chimney. not a continO- ouS ore body, nor a continuous vein with an ore DouE or chimney or chute upon it. As re marked the outcropping points indicate that thcrc 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. it's con- tinued satisfactory richness. and the promise il gives Of enrichment by further veins dipping into 1t on the foot-wail sides.
 Some facts in regard to the product or yield: The ore paid from the surface. The product or ore extracted up to the time has been about S1 tons per day, which is sent to the 20-Stamp mill each stamp of which cruSheS about tons in every twenty-four hours. The extraction iS chiefly and largely by power drills A force Of S0 men is employed by this mine and mill The greater part Of the labor underground and mining is done by compressed air. The lode, l 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 mill. They would prefer to reject most of this wall rock but it would take more time and cx- pensc than it does tO mill it. aud there iS chance of some Of it containing gold. From these S0 tons of rock crushed daily the average product is perhaps S4S00O worth of gold per month. Some months they have produced as high as T90,OO0.
 In the region of the Fortuna mine the forma- tionS appear to be wholly of mica slate and hornblende slate with some arenaceouS layers Ike old micaccouS SandStoneS and quartZiteS. The mine k surrounded by black hornblendic sOUthweStward at Gn angle of about 45 degrees. and these states are very evenly laminated ridge after ridge