| Show manganese deposits I 1 in n the colorado river region the search for manganese ores during the last two years has disclosed some promising deposits in the arid regions in the southwestern part of the united states one area which may be considered a unit extends southward from the great bend in colorado river near las vegas nevada and includes parts of dark clark county nevada san bernardino riverside and imperial counties california east of the meridian and mohave maricopa maricola Mari copa yavapai and yuma counties arizona west of a line running southward through wickenburg examinations of the manganese deposits of this area have been made recently by E L jones jr a geologist of the united states geological survey department of the interior location of the deposits many of these deposits were discovered since the fall of 1917 and some have since become producers the principal deposits enumerated from north to south are near ilas t las ve vegas veas as southeast of topock close to artillery mountains near williams river in mohave and yavapai counties arizona in the aguila district maricola maricopa Mari Alari copa county arizona zona in the maria and ironwood mountains riverside county and in the chocolate mountains imperial county california A few promising deposits are found along colorado river between needles california and parker arizona and many small deposits which have not yet been worked are widely scattered over the desert means mea ns of transportation the northern part of the region is served the los angeles salt lake railroad the central part by the main line of the at branch chison topeka santa fe railway and a branch line ne of the same road from phoenix arizona A arizona to cadis california which crosses colorado glorado river at parker and the south rii 1 part by the southern pacific railroad id d the california southern which extends I 1 ij to rom blythe junction on the parker cutoff cut off blythe be 1 although it may seem that this region ebion is reasonably well served by rail 0 oads s several veral large deposits ff are so difficult 4 access and d so remote from the railroad hat a the ov ore from them cannot be mard eted profitably Pt ably the producing deposits e he j aroln om a few w miles to forty five miles from railroad the ore is generally carried 0 the me ile T railroad by auto trucks but from 1 deposit sit ake on dorado colorado river the ore was a about Q parker forty three miles by motor boat 0 oad n and there transferred to the rail desert ert roads ds that graveled raveled ravel are continually I 1 by motor tor trucks j re must be repaired antly to hg facilitate transportation and ores arja aried fron from some me of the deposits must be to t the road on pack animals je dur burl production product io of resources the t to last year the deposits in this have e yielded more than tons of ore which contained 35 to 47 per cent of manganese 25 to 20 per cent silica and little iron and phosphorus mr jones estimates that at least tons of 40 per cent ore could be produced from the known deposits in this region but the geologic evidence appears to indicate that no single group contains more than tons of high grade ore though here and there several deposits that lie within a small area may yield tons most of the deposits contain from a few hundred to 1000 tons of ore the greater part of the ore is shipped to smelters shelters sm elters east of mississippi river and is used in making ferromanganese at the present rate of production it is estimated that to tons of ore containing more than 36 per cent of manganese will be produced during the last six months of 1918 kinds of ore the manganese deposits of this region are of two main types 1 veins and brec cias and 2 bedded replacement deposits possibly a third type of sedimentary origin may occur but it has not been definitely recognized veins and Brec cias deposits of the vein and breccia type are by far the most abundant and they are widely distributed over the whole area explored the veins are found in rocks ranging in age from the oldest and gneiss es which are precambrian pre cambrian to the youngest basales and conglomerates probably quaternary in the bighorn mountains south of aguila arizona the manganese bearing fissures cut both the old and rocks and the tertiary lavas that overlie them the association of manganese deposits with tertiary and quaternary lava flows is very striking and all areas where such rocks occur are promising fields for the manganese prospector the manganese deposits conta contained inea in fissures and zones were probably formed during the same geologic period probably the quaternary practically no other metals have been found in the manganese deposits of this type and they are therefore entirely different from the silver veins found in the tombstone and bisbee districts of arizona deposits of this type were noted in the las vegas district nevada in the topock williams agulla aguila bouse and parker districts arizona and in the maria ironwood and chocolate mountains california some of these districts however may contain also bedded replacement deposits the veins and zones range in width from a few inches to twelve feet and in length from a few feet to a few thousand feet the ores shoots within the veins and zones are from a few feet to feet long and extend from live five to sev enty five feet beneath the surface but their maximum depth in some of the principal deposits has not been determined the depth to which manganese oxides extend in these deposits appears to be dependent in part on the size and nature of the fissures and the kind of country rock As the oxides were formed by meteoric waters that circulated in the fractures it seems that narrow fissures or fisser fissures es in sheer zones might not be so favorable for deep seated oxidation as large simple fissures having well defined walls the deposits in rhyolite andesite and basalt are generally found in zones that have no well defined walls but some veins that cut rock and conglomerate fill simple fractures that have well defined walls manganese oxides the manganese oxides of the zones and fissures are and the hard steel gray manganese oxide is found in the outcrops of most of these deposits and appears to have been formed through the alteration of the other oxides in the ironwood and chocolate mountains has been found from the surface to the deepest workings seventy feet below but in most of the deposits in lava flows it is succeeded below at shallow depth by and commonly commonly occurs in stubby crystals in bugs or cavities in the ore but it also occurs in long fibrous crystals and aggregates as in the flynn property north of bouse the soft black manganese oxide is generally regarded as an alteration product of the manganese oxides in most of these deposits are not associated with iron oxides but the nodules of found in basalt or lavas that are rich in iron bearing minerals are commonly encased in iron oxide the most abundant mineral that persistently accompanies the manganese oxides is calcite but barite occurs in a few deposits quartz is apparently absent although fragments of siliceous rock are generally in the ore the manganese oxides of the fissures and zones are of secondary origin that is they were derived from some original mineral in the deposit the manganese was as an oxide and most of the remaining elements of the original mineral were carried off in solution calcite is also a secondary mineral and it affords the most valuable clue with regard to the original mineral which was probably calcite in a number of deposits at depths ranging from five to fifty feet the manganese oxides are succeeded by a coarsely crystalline dark colored calcite the dark color is due to minute treelike forms of manga manganese fiese oxides on decomposition this carbonate first yields the soft N manganese nang anese oxides which on further weathering and chemical action forms the hard found in concentrate cen crusts some of which however contain shells of to be continued |
