The Arizona sentinel., 1902-03-05
LA FORTUNA MINE.

In the early days of gold discovery Of Califor- nla lS4S when the news reached the gold miners Of sonora, there was q general exodus of the dble-bod1ed 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 few feet or yards of a very modest outcrop of quartz which no one seemed to consider of Suf- hclent value to merit any attention. That hum ble and significant 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 or the old maps the Gila range. This trends northweSterly and reaches nearly to the Gila river at the point now known as BlaisdelI. The railway in it's course to Yuma passes around the northwest point of this range w here the rocks are exposed at that point they are mostly of homogeneous granite of gray color and weathered out at the surfaces which. howcve are much pitted as if by decompoSi- tion Of some soft substance But beyond these Iow-lytng hills of granite there are big outcropS of rock which to the experienced eve indicate Stratitied formations. They are indeed strait fed for the bulk of the range Southward and SoutheaStward is composed of regular stratified lamlnated. hard gneiSSic rock. use the word 'gnelSS1c Tn very general and comprehensive sense, Tor you can describe these rocks with
 
 mica states and hornblendic SlateS with inter polations of quartZite beds. especially in the upper part of the series. with green stains Sun- 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. 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 talnS more copper than it now contains in the Inv nlg. .faff 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 chimney. not a contino- ouS ore body, nor continuous vein with an ore oody 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 it's con- tlnued satisfactory richness. and the promise 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 80 tons per day, which is sent to the 20-Stamp mill each stamp Of which crlSheS about tons in every twenty-four hours. The extraction is chiefly and largely by power drills. A force of SO 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 15 feet wide. This large space permits the use Of power drills to great adVant1ge. 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 1t would take more time and ex- pense than it does to mill it. and there is a chance of some of it containing gold. From these 50 tons of rock crushed daily the average product is perhaps 34S.0O0 worth of gold per month. Some months they have produced as high as S90.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 micaceouS SandstoneS and quartZites. The mine is surrounded by black hornblendic states and mica states dipping Southward and and these states are very evenly laminated, ridge after ridge.