Show ISO tell GEOLOGY OF STATELINE DISTRICT by judge gra groit ni H smith 1 Is stateline Stat eline mining district is located in southwestern utah in iron county and lies along the nevada state line the district is twelve miles long by two miles wide the principal mines lying within an area of about one mile square as shown on the map the mines were A ale I 1 I 1 discovered six years ago and many claims were located but the owners were not able to develop JUDGE GRANT H H SMITH them hem and were unwilling to let others do so on reasonable terms so that the growth of the district was slow it has been sure however and now the camp is about to take its place among the regular producers the town of stateline Stat eline is sixteen miles from modena a station on the oregon short line railroad and has a daily stage the wagon road is good and the mines are easy of access lying for the most part on rolling wooded hills the town lies at an altitude of feet and is very pleasantly located for a mining camp the climate is agreeable and work may be prosecuted throughout the year without inconvenience from snow or heat the hills are covered with pinion pine and cedar and good firewood is cheap and plentiful two small streams of water sufficient for milling purposes on a moderate scale flow down through the town tie the jennny mine is pumping sufficient water from its foot shaft to supply the johnny and ophir mills and it is probable that the other mines in the neighborhood will encounter more or less water with greater depth geology of stateline Stat eline stateline Stat eline range is one of the most extensive of the many small mountain ranges which dor corrugate the surface of western utah and nevada the trend of these ranges is northerly and southerly and the formation is usually of igneous origin to the north and south of stateline Stat eline the mountains are and craggy but within the mapped area they have been much worn down by the elements stateline Stat eline range is composed of eruptive crocks and seems to lie along and cover what was once a long wide and deep seated fis fissure from which a vast vasi amount of liquid rock flowed east and west vest building up a wide expanse of country and finally for forming mink the mountain range lilie like a huge dyke the early flows were of andesite tra chite tuffs tuff s and breccia later came the quartz porphyry which forms the core of the range and which probably lifted the earlier foit formation mation into a structure like the henry mountains within the mapped area the dome of the has been eroded leaving a large irregular irregular hilly basin and exposing an irregular belt of quartz porphyry or rhyolite nearly a mile wide and two miles long the porphyry is again exposed about about ten miles north of stateline Stat eline where the confidence and perseverance mines are located and and reab reappears several miles to the south where the promising min mines es of deer lodge wid arid pikes diggings are found there were several intrusions of porphyry each somewhat different in in texture and composition which made in parallel belts as if formed by the reopening of the great eruptive fissure the early eruptive rocks are not mineralized the quartz veins are all found in the porphyry the main body of porphyry is hard sili clous and iron stain stained jed and reddish or purplish in color it cavers covers the cen central triLl portion of the mapped area and in the quartz veins of this porphyry gold values greatly predominate the other small belts of porphyry which lie to the west of the main belt are lighter in dolor color looser in tex texture fiur 0 and more felde and the veins therein are largely silver bearing the utah spur little giant ophir burro venus high line and hope veins are in the silver belt while the other veins shown on the map are largely gold bearing the country rock is similar to the formation in which the mines of bodle bodie cal were found and is not unlike the comstock and tonopah porphyries ries ribs and cliffs of porphyry standing above the main porphyry mass and tending northerly and southerly y are a feature of the landscape these are locally known as dykes they are not separate intrusions but have resisted erosion by reason of superior r har hardness hardilek diles s which is due to a high percentage of silica these dykes are usually accompanied by quartz veins which abc acc accounts for the silica veins and ores the p porphyries ries were extensively fissured 4 A 1 4 lie Z 9 kv ta 4 A 14 k V q d A Z J 1 11 41 ja 0 an fn Z MAP showing N wt p aw CENTRAL portion OF MINING ai k 0 MON CO urah U rah Q and the fissures have been filled with quartz the main lines of fracture extend northerly and southerly and nearly all of the quartz veins in the district have been formed in north and south fissures the notable exception to the rule of northerly and southerly veins is the big east and west vein upon which the three principal mines of the district are located viz the johnny the margaret and the ophir many of the small veins and stringers of quartz occupy cooling cracks and shallow fissures on the porphyry and these sometimes contain rich ore the larger veins are quartz filled fissures that seem to have been opened by great pressure from below acting upon the porphyry mass after it had solidified these veins are persistent and deep seated and may be depended upon the principal ore bearing veins maintain a fairly uniform width of from three to six feet at times and particularly in the ore shoots they widen to ten or more feet there has been comparatively little faulting of veins when it occurs the faulting seems to be due aue to a later intrusion of porphyry As a rule the silver bearing veins lie between porphyry contacts and the gold bearing veins in the iron stained porphyry the north and south veins commonly dip to the west at an angle of from 50 60 to 70 degrees the east cast and west vein dips to the north at an angle of 65 degrees the droppings crop pings and explored portions 0 of f the principal ore bearing veins of the district are indicated on the map by dotted lines the country rock is frequently covered with wash and debris under which the veins disappear from sight but they almost invariably reappear on the next high ground the veins occur in well defined systems or zones as a glance at the map will show the principal veins may be grouped into four zones or vein systems as follows utah spur little giant burro and venus big 14 willowvale willowdale Willow vale crown point and free coinage jumbo gold belt and utica and johnny margaret and ophir it is probable that the creole vein belongs to the last named systems and the utah spur seems to be the extension of the ophir vein chica has swung sharply to the north the country rock along these zones is much sheared and fissured several parallel veins lie very close together and it has not been possible to indicate them all on the map the walls valls of the veins are generally well defined but at times the ore is a replacement of porphyry and gradually fades into the wall rock as the ore deposits at cripple creek often do the vein filling is white grayish or reddish quartz together with shattered quartz and porphyry and some clay which usually lies along the walls fragments of country rock somewhat decomposed and are often found enclosed within the quartz very rich ore sometimes makes about these fragments indicating di that they have been conducive to mineral deposition the veins often contain considerable fluor spar which seldom contains gold or silver in paying quantities black oxide of manganese is found in nearly 0 all of the veins and occurs in greatest abundance in the ore shoots the iron is rarely found in sulphide form the ore is generally hard close grained quartz stained with iron and manganese the richer portions showing in dark colored spots and bands there is considerable evi dence of crushing and secondary enrichment the ithe ores greatly resemble in character tho those se 0 of f bodle bodie dal cal of the comstock lode and of tonopah To ores found in this character of porphyry throughout the west usually have the same characteristics and are undoubtedly derived from the body of igneous rock at greater depth the ore usually occurs in well defined and continuous shoots in the johnny margaret ophir vein the shoots rake into the west at an angle of about 45 degrees and occur at or near intersections with north and south veins another noticeable feature of this vein is the fact that in the johnny ground the gold values largely predominate in the margaret the gold and the silver values are about equal while in the ophir silver values are largely in excess the ores of the district except those found in the silver veins are what are generally described as free milling the only metallic contents being gold silver a small percentage of iron in various forms and some manganese As a rule they are low grade averaging from 5 to 20 per ton very rich samples may be taken from almost any vein and considerable ore has been shipped that netted from 1000 to a car but high grade ore in quantity ignot is not common in the future everything will be milled on the ground the ophir is now treating its ore by the cyanide process after a slight roast and extracting 90 per cent of the values the johnny nill mill will extract the values by cop per plate amalgamation and cyanide treatment of tailings breakers and rolls are used in the ophir mill to crush the ore breakers and stamps in the johnny mill any of the ores in the district can be successfully treated by one or or the other of these simple processes at a cost of 2 per ton or less miners wages are 3 per day wood is plentiful at 3 per cord water is sufficient for all necessary purposes ore Is found in large quantities ties and can be cheaply mined and milled and there luevery is every reason to expect that St Stat kellne eline will be one of the most productive of the gold camps in the state for bior many years to edme come |