The Arizona sentinel., 1902-09-10
LA FORTUNA MINE.

In the early days of gold discovery of Califor mia, lS4S, when the news reached the gold miners of Sonora, there was 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 men to the mining population. They took the old road. which was known as the 'carnino real, from Estancia and Altar nOrthwestward nearly parallel to the gulf, following the mountain ridge known as the Ciila 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 6 very modest outcrop of quartz which no one seemed to consider of sui fcient 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 it's course to Yuma passes around the northwest point Of thlS 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 Stratihed formations. They. arc Indeed strait fled for the bulk of the range Southward and koutheastward is composed of regular Stratifed laminated hard gneiSSic rock. l 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 states and hornblendic states, with inter polationS of quartZite 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 to me the presence of some other mineral, possibly, tel iurium, 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 have been carried on here have developed a condition of things which could not be foretold from an inspection of the outcrop. The vein or lode appears to be a chimney, not contino- ems 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.
 crop; second in its continuity in depth, its con tinued satisfactory richness, and the promise Il 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 ol ore extracted up to the time has been about & tons per day, which is sent to the 20stamp mill each stamp of which cruSheS about tons 1T every twenty-four hours. The extraction i' chiefly and largely by power drills. A force of 80 men is employed by this mine and mill The greater part of the labor underground an( mining is done by compressed air. The lode, was told was to l5 feet wide. This larg space permits the use of power drills to grea AONdnbdge III IHG HdJtildl uOlSboO JIicl6 al fragments of the wall rocks, some of which ar thrown out, but many pieces pass through tn mill They would prefer to reject most of thi wall rock, but it would take more time and e1 penSe than it does to mill it. and there is
 chance of some of it containing gold. Fror these 80 tons of rock crushed daily the averag product is perhaps S48,000 worth of gold pc month. Some months they have produced a high as 800 000.
 In the region of the Fortuna mine the formf tions appear to be wholly of mica slate an hornblende slate with some arenaceouS layer Ike old micaceouS SandStones and QuartZite: The mine k surrounded by black hornblendi states and mica slateS, dipping southward an SouthweStward at an angle of about 45 degree and these states are very evenly laminatet ridge after ridge