Bisbee daily review., 1904-07-13

NHANh- vans tO luclT tdSlN dIu 4lD the thickness gradually increases away from the grano-diorlte contact, in which direction also the different beds succeed each other at the surface in ascending order; this fact is beIiey- ed to have an important economic significance since the various forma- tions from the lowest to the highest have been found to carry ore and thus strengthen the supposition that the rich lodes opened in the higher mem bers will hold their character as the strata are penetrated in depth. Nat urally, attention is now chiefly devoted to the mines situated some distance from the contact where there is still a good thickness of ground awaiting exploration.
 The most productive ore body in the early history of Tombstone is that known as the Grand Central-Conten. tion vein. It is not a continuous vern, but rather aseries of Ienticular deposits arranged en echelon and ex. tending north and south for nearly a mlle. The lenses usually lie not far from dike which has been silicifed ana otherwise altered. though con. talhing little ore. This great zone of mineralization was the chief obiect of mining by a number of the largest piouucers, including the Grand Cen. trai Contention. Tranquility. Head Center and other companies IT. is peheFed that the conditions favor the occurrence of good ore bodies beloU those already worked A seriAs of iinestones which have yielded richly m other parts of the district are eu. countered at depth Of 15O feet below ths former water level and will ba vis orously explored. The newshaft has been sunk in proximity to the vein so that the exploratory work may be conducted in close sequence to the pumping At present attention is aHected 10 the opening of the roo ,oot level. Some high-grade ore has been found in new ground west of tbe shait, discovery that lends epcour- asemen' to the view that this vein will continue to be productive in depth
 Al the West Side mine there is also a series of lodes extending along north and south Assure The ore oodies heFe partake of both the vein ana bedded character. The Assure cu's across line of fleuxering. a cir cumstanee that eveidently has been favorable to ore deposition. From the vertical vein the deposits reach mi into the country. occupying the crests and wings of the anticlines. The larg. est and richest ore body was fourd in a strongly compressed anticIine aoort 450 feet long. As elsewhere In this district. the bedded deposits seem to favor the limestones in pref erence to the quartzites and shales. owing probably to its greater sus- ceDubility to form cavities under the influence of compression. The west Side vein has been worked down to a depth Of 800 feet before pumping be gan. and development has since been extended to the sixth level.
 The Silver Thread mine is situated on the line of strike of the main Grand Centr<lContention vein. but is opened by an independent shaft. Recent ex- pioration has shown the existence of good ore bodies below the 4OO-foot level; they occur on the summit of cn antlcline in the vicinity of a dike The lowest workings in the mine are oniy 450 feet from the surface.
 Another of the old mines which promises 10 give good returns upop further development is the Emerald. IS situated some distance southwest or the main shaft. The strata con- prise hmestones and quartzites. but Of a lower horizon than those found in the mines to the north. The work ings were in rich ore when operations were checked by water on the seventh level.
 Altogether the territory covered by the mines and claims controlled by the present company is about two square miles. while the underground workings are of great extent. Many of the old shafts and levels have been found to be in good condition after unwauering, requiring only slight re pairs to make them of service for con tinuing the development It is evil dent that the consolidation of the va