Show i GEOLOGY OF DELAMAR NEVADA J W neill in M mining i s I 1 n g a and nd scientific press the de lamar mines are located in the meadow valley range about thirty miles by wagon road from calientes salientes Cali entes the rock formation is quartzite up tilted and dipping to the north and east on an incline of 30 degrees the quartzite is cut by three porphyry dikes which strike approximately east and west and by another porphyry dike which strikes approximately north J W NEILL C E and south with the strike of the quartzite beds and dips at an angle of 68 degrees to the west the ore bodies make at the intersections of the two major east and west porphyry dikes and the north and south porphyry dikes this latter has been the seat of profunda fissuring and this movement has fractured the tite of the sour rounding country on both sides producing two parallel fissures which are similar in strike and dip to the black porphyry fissure itself the east and west porphyry dikes are approximately feet apart at the nearest point and at this point the black porphyry which is the main north and south fracture cuts through both porphyries ries in relative age the east and west porphyries ries are probably the younger the quartzite is most profoundly shattered in the neighborhood of the corners of these three porphyries ries and in this locality the mineral solutions which have followed the fissuring have entered the communized comm united quartzite and have been most active the result has been the production of numerous ore zones which filled up the corners where the north and south dike has crossed the east and west dikes thus today these well known ore shoots have been developed in six of these eight corners and the other two corners give promise of producing equal results in the future the diagrammatic sketch herewith shows the relations of the several por phylies and fissures just it is not drawn to scale the known ore shoots are indicated in their respective corners and the empty corners are indicated by in two of these corners recent exploration has proved the existence of good ore bodies it is pertinent to state here that the material of the porphyry dikes no matter how much decomposed or how close to the ore bodies does not carry pay values these ore bodies have evidently been mineralized through the openings at the corners where the dikes make heir crossings and the quartzite which hale bat been broken into more or less small pieces has been re cemented by the mineral solutions into a compact mass of silica thus forming boales bodies of extreme hardness these ore bodies have had great areas in places over feet square and are developed from the surface to the sometimes on the foot wall side of the dike but without any well developed walls to the ore deposit itself further than this at least two of the parallel or fissures have developed ore bodies and one of these promises to be of very great magnitude and importance this is shenew the new hogpen hog pen shoot which lies to the south of and or feet away from the other and older ore bodies it is from twelve to eighteen feet in thickness and several hundred feet in length on the strike of the fissure and is of peculiar interest and importance aside from its com PLAN re poor EIL L U CIL I 1 IQ N E noa VE IN SHOOT Z W la 17 ea ld V J foot lev level ea and are now being developed below this level in addition to these shoots of ore in the quartzite there are several known shoots developed on the main black porphyry dike and partaking of the nature of regular fissure vein Tore shoots dit fering only in that the quartz quart jle adjoining the porphyry has been mineralized to a greater or less extent sometimes on the hanging banging and mercial value which is great as evidencing the fact that he ore bodies will make in the fissure in the ane quartzite away from the black porphyry itself the april fool mine has been developed on another series of fractures which are are parallel to the main black porphyry fissure and they resemble to a marked degree the ores produced produce 4 in the recently discovered hogpen hog pen shoot of the de lamar the ores of the quartzite bodies are peculiar in that they show no evidence to justify their commercial character it is a and often glassy mass of quartzite which under the microscope shows that it is very largely a readjusted or at least a cemented re quartzite the gold contents in these ore bodies is contained in exceedingly minute form practically never visible to the naked eye or in the pan but has yielded readily to the treatment by cyanide in the upper levels particularly in the of the black por considerable native tellurium has been found and strange to say this mineral is almost barren in gold which is contrary to local belief but this mineral has been associated with some of the richest ore bodies in the mine and is an indicator of the origin of the told gold from tel lu rides in some places in these tel eurides of gold have been found and it is probable that the gold throughout the mine has been and is more or less in this form in the new hog pen shoot the ore diff differs ers from the old parts of the mine in that it is more stained with iron and yields considerable gold to amalgamation which the old mine did not do the ores of the april fool fissure system are stained with iron oxide and moreover carry considerable silver values thus differing from the de lamar mine in this mine in several places the iron pyrites has been found in small patches i where it has been protected by a clay gangue Other otherwise wiser the ore is oxidized to the depth of 1100 feet and at this depth the values are still of commercial grade differing from both the de lamar and april fool mines the ores of the magnolia i group occur in a porphyry dike at the contact with quartzite these ores differ in character from the other two mines in that they are heavily stained with manganese and show a heavy peri percentage of free gold and contain silver values which usually average in the neighborhood of an ounce in silver to a dollar in gold development on this property has followed this formation to a depth of feet and the promises of the future are bright from the surface of all these properties very rich ores were taken out and much of it shipped by wagon to milford and thence to the smelters shelters sm elters at salt lake these ores abounded in free gold and to this fact the development of the camp is largely due the treatment of the lower grades called for the piping of water and building of mills the efficiency of the method employed viz cyaniding cyan iding is vouched couched for by the fact that fully 90 per cent of the meal values were extracted the camp has produced a gross valuation in the neighborhood of and of this fully one half has been in dividends which is certainly a very large proportion the present consolidation of interests under one company and one management manage menti with the enlargement of mill facilities and bh cheapening eapen the handling through the introduction ot of electric power will result in a renewed activity and renew a large production the plans now perfected will result in an outputs output this supposed to be worked out camp in the neighborhood of to per month |