Show description deschi ati on of high hi gh grade M mining n ng D district str ct california Cal calborn I 1 forn ia e BY JAMES M HILL ja the high grade district is located in the extreme northeast corner of modoc county cal in the warner mountains its northern boundary is the oregon line its eastern astern boundary is about seven miles west bof of the nevada california line and its western ern boundary is goose lake valley its southern limit is not yet defined as there ls a possibility of opening prospects south of f the present known veins press notices in the mining journals indicate that during 1913 the veins near willow creek five to six miles south of new pine creek were being ing developed in bulletin U S geological survey history of mining As far as can be learned the discovery of gold in the high grade camp was made on the oregon claim at the south end of the district in 1905 by a sheep herder who sold to J 0 kafader of fort bidwell there is a story current that a scout by the name of hoag while stationed at fort bid well about 1870 prospected in the warner mountains and brought in some gold before he could go back to his claims however he was killed in an indian skirmish and all trace of his find was lost because of this supposed early discovery of gold in the district it was first called the hoag district which name was later changed to high grade the first local boom took place in the summer of 1905 but the autumn of 1909 and spring of 1910 witnessed the big rush to the district accessibility until the spring of 1911 the nearest railroad was at alturas alburas Al the seat of modoc county fifty two miles south southwest of 4 ILI al iga A i N Z A him the sunshine mine and surroundings high grade california the camp in 1912 the neva nevada da california oregon railway had been extended along the east side of goose lake to lake view the town of new pine creek one mile off this road on the california oregon boundary line is eight miles west of the district ani and is the supply point for the miners the roads from the town up pine creek to high grade are in fair condition though many steep grades and switchbacks switch backs are necessary to gain the top of the range A mail stage operates between new pine creek and fort bidwell going by way of the new camp high grade is plentifully supplied with deep creek and bidwell creek which drain northeast and southeast respectively the most prominent peak on this divide is yellow mountain which has a barometric elevation of feet this peak has a steep western face hut but slopes off at a gentle angle to the east under mount bidwell el V aw camp of the modoc mines company high grade california timber and water though there is hardly enough water in the vicinity of the mines to generate power it is an ideal summer camp but it is said that from the middle of november until late in june the roads are practically impassable on account of heavy snows topography the warner mountains in the vicinity of high grade are rugged but have a fairly even crest at an elevation of feet mount bidwell about three miles southeast of the camp attains an elevation of f feet e e t the west front of the range has an abrupt rise of 1000 feet above the level floor of goose lake valley which is about feet above sea level this rise is along a fault which follows the east cast side of the valley for bior a considerable distance the scarp is modified by erosion and several good sized streams have cut back into the range the canyon cut by pine creek followed by the high grade road has very steep sides for about three and one half miles eastward from the town of new pine creek it has an even rise of about feet to the mile but in the next one and one half miles there is a rise of 1000 feet the east front of the warner mountains was not visited by the writer but it is shown on the alturas alburas topographic sheet as an abrupt rise russell shows a fault scarp along the west side of surprise valley the mines so far opened in the high grade district are located along the summit of the range at the headwaters of new pine creek a westward draining stream and geology general features feature si the lower feet of the hills immediately east of goose lake is made up of purplish and greenish beds of andesite tuffs which form the walls of pine creek canyon for about two miles sites which are the oldest rocks in t m he e cikity of the mines v y in the high grade district I 1 proper ther n four distinct types of are extrusive give lava la vaa the oldest rock exposed along the lo 10 1 1 western side of the district is a dark fl grained andesite above this is a whit whiter 4 yellow rhyolite that in some places is buffa tuff bous but in most places is finely gran granule lilar above this rhyolite on the flat eastway basti east War slope of alturas alburas ridge there is a purplish flow rhyolite with very fine lamell lamellate lamellae lam ellae a e A 8 fresh basalt is exposed on the west flanks of 01 mount bidwell and presumably forms the summit of this e cm indence andesite the andesite in the western western part of the district is composed of dart dark gray to green flows dipping ea east st at low 61 angles all the ande sites show distinct floy gow 0 structure and some of them are in part glassy the andesite on oil the V south side of discovery hill though the best preserved rock of this type seen is much altered the rather small plagioclase are largely altered to chlorite and some calcite the groundmass is composed alt of plagioclase laths baths and magnetite 2 the plagioclase being largely altered all B the f erro minerals are altered te ie yond recognition the feldspar crystals in the groundmass distinctly bend around the contact of andesite with rhyolite on the ridge about two miles west northwest of high grade the yellowish rhyolite over 9 d lies the andesite in the valley of pine M W discovery hill high grade klondyke klon ej california on which are located the ft bidwell consolidated gold peak north mort r OA star and 1 I other mines from its mouth overlying these tuffs and dipping east at low angles there is a light buff colored to white granular rhyolite which forms the canyon walls to a point about one fourth miles above the s sawmill a w m 1 11 where there is a series of dark brownish soda rhyolite flows followed by the ande creek the contact is covered b by Y gla glacia ca i bat raa aerial but it is probable that it is a Is k contact contact contac tr at the foot contour the 0 the again seen about feet below m mit i t of discovery hill at an elev elevation alevato atO at of 09 feet but in sunset creek it lies tt the gres elevation of only fet difference if ference in elevation of the andesite rhyolite contact at different places is probably bly due in the main to faulting though some of it may possibly be attributed to erosion of the andesite surface prior to the outflow of the rhyolite rhyolite the rhyolite that forms all of yellow ellow mountain and high grade hill and the northern part of discovery hill is white abut but weathers yellow it consists largely of I 1 the granular quartz and orthoclase with here and there a very small amount of on the western slopes of high grade hill and yellow mountain there is about feet of yellow rhyolite tuff below the granular rock the majority of the rich veins of the camp are found in this rhyolite glassy rhyolite on alturas alburas ridge there jis is a small area of thinly laminated purple rhyolite under the microscope this rock is seen to be in large part a glass in which there are a few crystals of quartz and ortho ielase clase its relation to the granular rhyolite described above was not definitely determined ter mined though it appears to be a down faulted rock and is presumably younger I 1 than the granular rhyolite basalt basail the basalt on the west flank of mount bidwell is a perfectly fresh greenish black porphyry that weathers dull brown the few cheno crests are quite large and well developed the groundmass is composed of andesite pinkish gray almost colorless olivine and magnetite named in the order of decreasing abundance on the road from high grade to branley about one eighth of a mile south of the pine creek fort bidwell road crossing there is a small exposure of black volcanic glass obsidian which shows columnar structure structure the various flows described above have a low eastward dip being part of the tilted fault block that forms the warner mountains the faults along which this block has been raised are on the west side of surprise valley and the east side of goose lake valley along the goose lake valley fault the vertical movement iwas was relatively greater than along the surprise valley fault which resulted in the structure of the region visited there is some evidence of minor faulting near the summit of the range and it seems probable that there is a rather large fault about three miles east of the goose lake fracture no definite evidence of this was seen as the writer spent most of the available time at the mines there is however lio wever a strong suggestion of such a fault in the f abrupt rise in pine creek canyon at that point and a series of cliffs in the south branch of pine creek the of the high grade district took place along the minor fractures near the summit of tile the range rock piles the so called rock piles of hh hi ig gh grade hill and the north slope of discovery hill are as the name implies piles of angular talus blocks up to six feet in longest dimension this talus in some places is twenty feet thick but is usually five to ten feet the principal veins so far disclosed are near these piles and prospecting for them is rendered difficult on account of the necessity of moving so much loose material these accumulations of talus are the result of differential weathering the rock of which they are composed is highly rhyolite which weathers much less rapidly than the ordinary unaltered rhyolite this unequal speed of weathering has resulted in the disintegration of the surrounding softer rhyolite leaving knobs of the more resistant rock the action of the freezing of water in the small cracks penetrating the rock has split off the large angular blocks the depressions around the base of some of the piles are to be explained by the fact that much of the disruption of the knobs has taken place when there was deep snow on which the blocks have fallen when this snow melted it dropped its load in an irregular fashion in most of the talus piles some snow can be found throughout the year evidences of there was a small glacier in the main fork of pine creek between high grade hill and yellow mountain which carved the steep north slope on yellow mountain and formed the low moraines mo raines which have dammed cave and lily lakes the ice did not move far so that practically all the material in the moraine is angular angular there was also a much smaller ice field in the south head of pine creek west of discovery hill which formed the basin now occupied by south lily lake the seems to have been restricted strict ed to the western side of the warner mountains in this vicinity as there is no evidence of ice erosion in the valleys of either sunset or evening star creeks ore deposits types there are three rather distinct types of ore deposits in the high grade district CD 1 veins in granular rhyolite with some replacement of the walls 2 veins in andesite 3 veins and replacements in glassy rhyolite the veins of the kind first named yield the largest amounts of ore gold cold alloyed with some silver is the valuable constituent of the ore and in all places so far opened the gold occurs free minor amounts of copper silicate and a little carbonate were seen in the veins in andesite origin and general features of the veins the development work in the district consists largely of open cuts and shallow shafts so it is not possible to draw final conclusions it appears however that the of cfall a 11 the types occurred at about the same time the solutions came up along fractures partly filled with brec breccia cla especially in the rhyolite areas the principal veins occur in nearly east west vertical fissures though north south and north west southeast fractures are not unknown the was accomplished by hot siliceous solutions carrying gold silver iron and potassium which altered the wall rocks near the fissures by the addition of potassium to form quartz and rock in practically all the veins movements have in places crushed the ore and produced gouge which though seen in places between the wall and the vein quartz is commonly found in the quartz where the wall rock was too tough to fracture the clay gouge of almost every vein constitutes the richest ore showing a secondary downward concentration of gold from the parts of the veins that have been removed by erosion veins in granular rhyolite occurrence and development the veins in granular rhyolite are found on high grade hill on alturas alburas ridge and the north side of discovery hill in all these places the granular rhyolite has been more or less particularly along zones of cia tion the result being that the rock has become exceedingly hard on high grade and discovery hills this hard altered rhyolite has weathered into the so called rock piles the veins of this type are usually associated with these areas though there are some veins in un rhyolite in these veins the best ore occurs in shoots which pitch east or southeast on the veins at medium angles the yellow jacket vein shows most clearly the character of ore from the zones in this fracture there are ten inches to two feet of breccia partly cemented by quartz and some with small open cruses lined with clear quartz needles the light colored bands near the edges of the rhyolite fragments contain and a little pyrite the dark bands that come next are stained by iron oxide outside of this the first materials deposited in the cavities are irregular light colored bands which are generally quartz but in some places show crystals of adu Iaria as well clear white quartz was the last mineral deposited in the process of tio ii the gold occurs as very small part particles in the dark and light colored bands between the altered rhyolite and the white comb quartz it is rather light yellow and apparently contains considerable silver the sunshine vein cuts rhyolite breccia but the ore consists of milky white to gray quartz and which has been crushed and later clear glassy quartz needles deposited in the brec breccia cla the mountain view vein was not studied but it is said that the rhyolite it cuts is not though the ore contains wall rock with quartz I 1 on the cliffs between tl the ie two heads of 0 evening star creek there are several prospects in granular rhyolite some of 0 which show no veins the rhyolite is iron stained and is said to assay fairly well in gold over a width of several feet these areas are arc all near fissures and this may possibly be somewhat similar to that seen in the walls of the modoc vein which are said to be gold bearing for several feet from the fissure the development of this type of deposits is more extensive than that of any of the others but it has been scarcely sufficient to show more than the general features or of the veins A few of the more important workings are described below modoc mines the modoc mines co owns the south half of section 36 town 7 4 01 at 4 A 41 W 01 J five foot face of ore in the sugar pine mine of the ft bidwell cons mining co high grade california ship 48 north range 15 east with the exception of the last dollar claim in the southwest corner of the section the country rock under all this ground is granular rhyolite with the exception of a few small areas of obsidian the crest of high grade hill is a rock pile in the early part of august 1912 the principal development was a 60 foot shaft with short drifts at the 50 foot level in the northeastern part of the ground though p there were several |