Bisbee daily review., 1910-11-26

! Hey in the class of 1905 and since his gradual on has spent one year in Chi na and three in the Philippine Is lands in the employ of an English mining company He has just return ed from more than a months examiD-
 ation of Horse Shoe basin, in tho
 Quijotoa district. and what he has to say about that district merits the consideration of business men:
 | The problems of the successful and economical winning of gold from dry piacers is one that seems to have never been seriously and systematl- cally worked upon up to within the present year. Fields that possessed deposits of great richness. such e the Beludo district in Altar, have yielded profits in spite of, rather thar because of the way they were treated. | Where there are rich natural rifles In the old river beds. they have yield ed profits to the man working them by hand, and in those old river chan neis in California drift mining ou the sIavels, where there has been an abundance of water for the final saving of the gold. has been very profitable: but the treatment of such deposits as occur on the arid desert regions of Arizona, have never re cefyed the careful thought and sys- itematic treatment that their values deserve The condition at Quitotoa. Pima county, Ariz., some 90 miles southwest of Tucson are typical of 1 this class of deposit
 On the western side of the Qui- iotoa valley. a broad fat valley twen- ty odd miles wide. lie range of hills Ia few hundred feet high. sharp and jsteep, with the edges of the valley upturned on its Hanks and shattered and broken on the clearly lined con- tact and the hills were thrust up through the ancient plain. Along the edges of this zone of shattered plain formation, and in the short course of canyons debouching on the present plains, are hundreds of gopher work ings from 10 to 35 feet deep. where | the Indians and Mexicans for years out of mind, have mined the weath- cred and fractured gravel beds of the primary and the softer beds Of secondary enrichment in the present water channels.
 ! The plains are covered with from ] two to ten feet of hiH wash, overly ! ing beds of lime cemented gold bear [ ing grayels locally called "caliche" Tor ragua masse." Only the softer portions of this cemented gravel could be worked by hand, because Of the difficulty of disintregating 1t. During the last fifteen years the local trader has bought over sI00,e00 worth of gold from the restricted workings of the Indians, the gold he- ing of a fineness exceeding sls.50 per OF. and of a size ranging from 1 mall but fat" colors up to nuggets weighing over 50 oZs.
 Taken as an average the extent Of the Indian workings is small. and work was done, not according to the richness of the ground, but according
 its workableness or softness. The crushing of this cemented gravel has never been successfully done by stamping because of the excessive cost of crushing large ton nages. but the introduction of the Quinner machine. with capacity of 25 to 30 tons per hour. a power con sumption of 35 H. F. and delivered product of the desired fineness. has been the first step towards opening up this class of deposits to exploita- ton on large plan.
 
 preparing the ground has been de cisiyely proven by the work already done by the Horse Shoe Bend Placer mining company plant at Quijotoa, where a Quinner easily handles this tonnage, delivering a pulp wherein the cement Is crushed 10 a fine pow der and coarse gravel crushed to A Inch. As the gold is held in the in- terstices of the gravel by the ce- ment. the thorough disintregation Of this cement is the important thing.
 The second step in the process, that of seperating out the gold, was first tried by using large power driven machines of the old type hand dry washers, where an intermittent up ward current of air is the floating medium for carrying the pulp down steeply inclined riffle tables.
 The large quantity of magnetic iron present soon clogs the rifles, after which the rest of the gold and iron moves over the rifles and is lost. If the tables are cleaned often enough to prevent this clogging, they cannot handle sufficint tonnage
 A new type of table, similar to a Wilfley table, by using a flow. of air from slots in the table top for a floating and moving agent, draws ofY the gold and iron continuously and automatically, the iron then beng a distinct advantage as it carries along with it even the finest particles of gold.
 While there has been a host of dry seperating machines put upon the market. the Stebbins table is one of the few that have been perfected thai can automatically make a clean sepa- ration with a large tonnage. The large tonnage can only be secured by a machine that Is automatic and con tinuous in its action. To one who is unfamiliar with this class of work. it is a revelation to see the metallic content of the ore separating out from the waste. the latter moving of the side of the table and the metal lies following the rifles lengthwise Of the table and into the hopper at the end
 The Wilfiey type Of wet concen- =