The Arizona sentinel., 1900-09-26
LA FORTUNA MINE.

| mia. 1S48 when the news reached the gold miners | of Sonora, there was a 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 to the mining population. They took the old road which was known as the ''camino real, '' | from Estancia and Altar northwestward, 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 a few feet or yards of a very modest outcrop of quartz which no one seemed to consider of sui ficient 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 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 Gila river at the point now known as BlaiSdell The railway in its 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- tion of some soft substance. But beyond these low-lying hills of granite there are big outcrops of rock which to the experienced eye indicate stratified formations. They are indeed strait fled, for the bulk of the range southward and southeastward is composed of regular stratifed, laminated, hard gneiSsic rock. I 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 mica slates and hOrnblendic slateS, with inter- polatiors 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 presence of some other mineral possibly, tel lurium, which by its decomposition has given these colorS. The fact remains however, that the bullion from the upper part of the vein con- talns more copper than it now contains in the lower levels Of the mine The workings which have been carried on here have developed a condition of things which could not be foretold from al inspection Of the outcrop. The vein or lode appears to be chimney, not contino- ous ore body, nor a 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.
 The vein is remarkable first in this limited out crop; second, in its continuity in depth, its con- tinued satisfactory richness, and the psomise it gives Of enrichment by further veins dipping into it on the foot-wall 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 30 tons per day, which is sent to the 20-stampr1ill, each stamp of which crushes about tons in every twenty-four hours. The extraction is chiefly and largely by power drills A force Of 80 men is employed by this mine and mill. The greater part of th labor underground and mining is done by compressed air. The lode, I 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