Show mine mi ne and mill ma 11 of bannack gold mining company BY WILL C HIGGINS bannack mining district in beaverhead county montana dates its early history back into the sixties when placer mining for eor gold made that section famous the world 6 javer ver bannack was among the first placer gold discoveries to be made in montana and its its diggings produced many mili millions lons in the precious metals before the quartz lod lodes esthe the erosions ero from which without hardly a question of doubt formed he placer deposits in he e gulches b below e I 1 0 w were ere discovered the ledges which furnished nearly twelve millions in placer gold so far recovered being located on what is now the holdings of the ahe bannack G gold 0 id mining company the property of the bannack gold mining Oom company pany composing the golden leaf lea group of eight lode claims besides in interests ter in placer claims jests Mill sites w ag a g 0 n roads ditch and water rights is located near her ber of prominent engineers after which the present organization was perfected john F cowan president W C ebaugh secretary and treasurer G T hansen managing director the other directors being W S mccornick and B binnard the company is capitalized at shares of 1 each main office kearns building ing the cyanide system of treatment which without a question of doubt will be one of the most perfect and up to date cyanide plant installed in this western country the first unit of this plant which should be in ill running order by the fifteenth of the present month will be of tons daily capacity with foundation and power for double this capacity V te T S e R rna a 41 ax A K 7 1 4 t at x nife 1 0 r 5 5 7 4 the priscilla tunnel bannack gold mining co the ane or of twenty three miles west of dillon the county seat of beaverhead county the nearest shipping point from bannack is grant twelve miles distant a station on oil the pitts burgh gilmore railroad which connects with the oregon short line at armstead it is now only a few months ago that the golden leaf group was taken over by lithe lahe bannack company after exhaustive tests and examinations had been made by a num salt lake city since its incorporation the company has been actively engaged in ill the performance of exploratory work in the measuring up of great bodies of good milling ore left standing by prior owners who mined and shipped on only ay high grade ore years before milling methods had attained such a state of perfection and it has also been occupied in in the c construction 7 of a milling plant involve elsewhere in this article the milling plant together with equipment and flow sheet is fully in a report on the companas comp anys proper property ty recently sent to stockholders general manager mans hansen says say s in part geological formation the map of this district shows that the ore bearing formation is in the shape of an all irregular ellipse and follows the zone of contact between limestone and syenite the entire center of the ellipse is syenite outside of which ev grything ery thing is lime with isome beds of quartzite from every direction from the mine the country is covered by this vast body of cretaceous creta cious limestone of unusual thickness as proven by the openings in the mine as well as by the great bluffs above grasshopper creek these beds at one time apparently formed a vast tableland but later through erosion were broken down to the present appearance of a low range of hills through these lime str strata ata in late geological time there was intruded a mass of syenite from one and a quarter to one and one half miles in diameter around the edges of this syenite is formed the irregular but well marked vein on which the claims of the company are located the contact of the lime with the clenite made almost ideal precipitating conditions for gold especially in the presence of the iron sulphides sulp hides which with a gangue of lime quartz quartzite and altered syenite make 4 1 4 iv 7 C a A type of permanent ore chute construction in connecting raises bannack gold mine up the vein filling some of the higher points of the lime have been protected by the overlying quartzite notably the top of the hill above the claim in general the width of the vein varies v aries considerably as must be expected in a lime contact in some places it narrows down to a foot or two in width and then within a short distance opens up to thirty or forty feet across contrary to the general rule the best ore is usually in the widest parts of the veins there are many eaves caves in the lime which are often filled with shipping chipping ore in general the ore makes in the lime the ore for the most part is very soft it varies in color from dark red through all shades of brown and yellow due of course to the oxidation of the original iron sulphides sulp hides in the vein in some places however the filling is all a rotten quartz with but little stain although the ore is so soft that but little blasting is done in the vein proper the ground stands exceptionally well there are many old in the property which have stood without caving for many years it is not unusual for two miners while drifting to pick down and load twenty tons of vein matter during an 8 hour shift in some places the vein matter is slightly harder as in the north end of the golden leaf where a considerable body of harder iron has been encountered this condition is indicative of good ore below in shipping ore A large tonnage of 0 shipping ore has been removed from the property estimated at over which must have hav e been of excellent grade for the remaining dumps are small and for many years the rich ore was hauled by ox teams to salt lake city leaving in the mine large reserves or the lower or milling grades 0 of f ore A while the gold as stated usually occurs along the contact between the limestone and the syenite it also makes out into the bedding planes of the lime and along fissures f which traverse the mineral formation along this contact formation the mines have now been opened by feet of workings to a depth of feet showing the ore to occur in shoots th alfe e high i grade bodies in lengths of from fifty to feet and the milling ore bodies of much greater extent the ore is thoroughly oxidized and is generally very soft the bodies varying in i n size from four to thirty feet in thickness and averaging about ten feet there is no water in the mine which favors the solidity of the enclosing wall rock and makes very little timbering necessary and there being no hoisting except for the ore below the main mill tunnel level together with the fact that fully one half of the ore can an be mined without the use of powder makes the cost of mining proper very low not exceeding 1 per ton including development the tonnage in sight in figuring the tonnage technically in sight in the property the irregularity of the workings makes the results of the usual calculations more or less approximate but on the other hand so much exploratory work has been done and so many ore faces disclosed that estimates of reserves are more likely to be under than over the true tonnage up to june 1st ast last it was 3 ively figured at ton tons 0 of t 1 C 10 gold value per ton ready for in y at that time all ore had been de devoid melode 8 lt 1 through the mining of high grade con de quent ly the averages shown wn had b e 1 stripped of all higher values 01 1 the priscilla tunnel the main vork 14 ing adit has been driven feet to abe tl contact at an elevation of binet ninety Y feet a aw to creek level the point of intersection I 1 0 fj this tunnel with the contact is feets feet i low the surface the highest point of the th contact on the surface will be feet a nye alov the priscilla tunnel A body of ore nisei alt feet wide by feet long was developed dev elope on this level all car samples during thil thi development averaged per ton we have raised through this ore forty fe feet et anji an sunk sixty feet the grade is increasing with depth we will continue sinking t i water level which according to indic indication atio s aw aw 0 4 not 14 41 41 flume portion of the power system bannack gold mine will be fifty feet below creek level or lh feet below the priscilla tunnel level working raise through solid limestone cos CO the priscilla tunnel with the golden leaf j in tunnel and priscills pris k laid in the new track has been tunnel golden leaf foot level waa ivallas tunnel and the 36 foot level and the tan the nels straightened where ne necessary ces sary rad 1 workings have been connected b by y ore I w waste a ste chutes the mine is ready for oper for t i oil in the golden leaf there is a large d fo ady dy 1 of disintegrated white quartz through deshich de which we have raised feet it averages h fa IG 61 per ton at the top of the thomas in line we have opened up tons of ore ive ve raging 5 per ton in the thompson katope isope we have opened a face of high grade opre re P three feet wide assaying per ton rave ye have not determined the extent of this W shoot dhoot in the corkscrew raise we have r riven ninety feet through an from few chich chich car samples gave an average of 70 1 er ton in the jacobs six feet of d ore k re assays essays per ton in the 11 line ine the green raise has developed an ore boot hoot feet long having an average width yf f eight feet and an average value of 1720 allis his development is in virgin territory be I 1 ond the old workings and is an encourage ig 9 indication of what we may expect in ur portion of the contact A I 1 abw ew on the foot level of the X iden bolden leaf shows a width of twenty two beet et and averages 1120 per ton in the 11 I 1 unction there is a body of ore twenty feet kide de exposed for a distance of feet n i length with backs of feet in the opper the silver the hand laft haft the huber the springfield laft haft and the mizpah tunnel we have open CL 1 up large bodies of ore which grades well IT bove the averages shown by the original es serves erves in all development we have kept rec ds of ear car samples of the ore taken from ie e mine to our ore storage dumps these chimples amples are representative and have averted 1540 for all ore to date the management estimates that in the ine workings there are tons of ld id ore in sight ranging in value f from rom 6 to 12 per ton while since being taken ver mgt by the present owners new ore t to 0 the extent of tons has been placed in ight averaging all the way from to to the ton in addition to these known nn ages mr hansen says we are work ig on ten new ore faces which are develop g grap rapidly idly this estimate of tonnage concludes he ie report does not take into account any re e below the present priscilla tunnel level this level and the level of tho the eek there is ninety feet of depth and this art of the property may be expected to pt it in sight at an early date at least anther ather tons of ore as a result of the developments now under way ore reserves tre re at present four years in advance of he ie mill mining developments and costs will not be in excess of 1 per on we should have no difficulty in mainlining graining gla an average mill heading of 10 per el on starting june therefore we an cipale a net profit of per month sar r 30 per cent on the capitalization per blenum annum mining probabilities are ed and earnings will increase with the natural growth of the enterprise the cost of doubling the mill capacity will be 11 since the sending out of the report above quoted frona from a has been sunk from the priscilla tunnel level to a depth of feet without reaching water level the being sunk the entire distance in an oxidized ore of excellent value on the fifty foot level in the a crosscut has been run a distance of feet in a northeasterly direction all in ore and without exposing either wall of the vein the priscilla tunnel is the main working tunnel for the handling of ore practically all distribution of timbers and handling of waste being accomplished through the golden leaf and wallace tunnels above the workings above the priscilla tunnel are connected to that tunnel with heavily timbered large capacity ore chutes which extend from top to bottom of the mine effectively connecting for cheap operation all of the levels and opening to immediate operation the various ore faces which are now available |