The Arizona sentinel., 1902-08-06
LA FORTuNA MINE.

In the early days of gold discovery of Califor- mia, 1s4e when the news reached the gold miners of Sonora, there was general exodus of the able bodied men who were able to get away northwest to the new Fl Dorado in California and the state of Sonora contributed many men 10 the mining population. They took the old road, which was known as the ''camino real from EStancia and Altar northwcStward, nearly parallel to the gulf, following the mountain ridge known as the Gila range, just north of our present boundary. The road led to Yuma, and in passing the Gila range they went within few feet or yards Of a very modest outcrop of quartz which no one seemed to consider of sui hcient value to merit any attention. That hum bie and insignificant quartz outcrop is today the outccop of the great Fortuna mine.
 It is situated on the westward slope and nearly 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 Ciila 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 color and weathered out at the surfaces which. however, are much pitted as if by decompoSi- tlon of some soft substance. But beyond these low-lying hills of granite there are big outcropS of rock which to the experienced eve indicate stratifed formations. They are indeed strait fled, for the bulk of the range Southward and southeastward r composed of regular stratified laminated hard gneSSic rock. use the word ',gneisSic'' in a very general and comprehensive sense, for you can describe these rocks with much more accuracy if you lOcaliZe them as
 
 poldtiOnS 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 all though there are peculiaritieS of color, and some yellow colorS, which indicate to me the presence of some other mineral. possibly tel luriUrp, which by its 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 hoN hpn ind I,.nr.a h.-- ao,-o condition of things which could not be foretold from an inspection of the outcrop. The vein ar lode appears to be chimney. not a contino- oue ore body. nor d continuous vein with an ore body or chimney or chute upon it. As re- marked the OutcrOpping points indicate that there is no very great longitudinal extension of this ore body.
 Thevein is remarkable firsti in this limited out crop; second. initS continuity in depth its con- tinued satisfactory richness, and the promise it gives Of enrichment by further veins dipping into it on the foot-wall sides. Some facts ln regard to the product or yield: The ore paid from the surface. The product or ore extracted up to the time has been about 80 tons per day, which is sent to the 2O-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 go men is employed by this mine and mill. The greater part of the labor underground and mining IS done by compressed air. The lode. I was told. was to I5 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 arc thrown out but many pieces pass through the mill. They would prefer 10 reject most of this wall rock but it would take more time and ex- pense than it does to mill it. and there is chance of some of it containing gold From these 30 tons of rock crushed daily the average product is perhaps S4S,000 worth of gold per month Some months they have produced as high aS S9OOO0.
 In the region of tho Fortuna mine the forma- lions appear to be wholly of mica slate and hornhlende slate, with some arenaceous layers Ike old micaceouS SandStoneS and quartZiteS The mine is surrounded by black hornblendic slates and mica states, dipping Southward and southwestward at an angle of about 45 degrees, and these states are very evenly laminated. ridge after ridge.