Arizona republican., 1918-02-03

ganese, and from to p per cent of silica, with little iron. The greater part of this ore would probably carry less than 8 per cent of manganese. Further exploration is reported by MT. Graham to show not less than 10000 tons of ore from which he estimates 3o,OoO to 5000 tons can be mined that will average 3S per cent of man ganese.
 It is evident, at any rate. that S , large quantity of ore is available which requires little or no sorting to be made marketable, and a still larger quantity remains that can bv | improved in grade by concentration that is, by separating the hard man l ganese oxides from the sandstone matriX. The deposits offer exception al advantages for cheap mining. they lie at the surface, large areas ! of clean ore being exposed with no overburden. and are readily accessible to trucks or other means of convey
 ance.
 The manganese deposits occur in lowlying ground at elevations above sea level not exceeding 1000 feet. along an arroyo that drains to Will
 Hams river. The largest deposit oc- CUTS near the head of the arroyo. in a basin that is partly enclosed by a
 basalt rim which at some places rises 500 feet above the deposit.
 Red and brown slightly indurated l sandstones and interbedded clays
 comprise the rocks of the small hills
 in the basin along the course of the
 arroyo. They strike about N. sos
 W. and dip 15s & W. In places the
 periodic flood waters of the arroyo
 have cut narrow channels with verti-
 cal walls 50 feet high in these sand
 stones About miles north of Will
 Hams river the sandstones are com
 fortably Overlain by a coarse pebble
 conglomerate. Both the sandstones
 and conglomerate are probably of
 late Tertiary age. The basalt flow
 overlies the sandstones and con
 glomerate and forms the rim about
 the head of the basin. The lava
 gives off abundant talus. which ef-
 fectually conceals it's contact with
 the underlying sediments and extends in places over the manganese deposits.
 The basalt is believed to have been
 formed in the Quaternary epoch.
 The exposed manganese ore is re-
 placement of the topmost stratum of
 the sandstone. Three principal de
 posits occur in this arroyo but other
 smaller deposits of similar origin arc
 found in sandstone in a zone said
 to he 15 miles long. The largest de-
 posit exposed is 500 feet long, about
 300 feet long. 100 feet wide. and i to 4 feet thick, caps a hill 200 feet high. About 1l2 miles south oi these deposits a third deposit, S0( , feet long. 100 feet wide. and 3 to 7. feet thick. is exposed on both sides of the arroyo. On the south side of Williams river, miles east oi Tappan ranch. a deposit 200 fee ] across and about ? feet thick forms $ the capping of a small hill com : posed of red sandstone.
 The ore consists of manganese OK $ ides that have replaced the mineral: of the sandstone without destroying it's texture It is hard, and the re placing mineral is amorphous anC 5 is probably psilomelane, which 1T places forms characteristic botryoida , and mammilary masses on the sur faces. The replacement of the sand stone beds is variable; much of tn ore contains visible undeplaced quart grains, which represent most of th silica. In addition scales of calcit
 and gypsum are commonly foun'
 in the ore, but they are nowher . abundant.
 , All the evidence points to the con clusion that the manganese ores wer :, deposited in the sandstone beds iron ' waters which percolated through tn II overlying basaltic rocks. These de t posits are different from the othe : known manganese deposits of Arizona T but are similar to many deposits il u the eastern United States and [ 5 some in foreign countries.