Show ELECTRIC GOLD DREDGE OF THE CONREY PLACER WRITTEN FOR THE MINING REVIEW the conrey placer mining alining company at ruby montana has in commission three gold dredges 0 operating pe rating in the flat at the mouth of alder gulch madison county state of montana this gulch is historic for the arge amount of gold extracted by the pioneers in the sixties and later two of the conrey company dredges are operated by steam one having first started in 1899 the other in 1902 since then the art of dredging in corn com act auriferous gravs has advanced so uch and the practice so thoroughly established on safe mechanical lines that much thought has haa been given to the perfecting and cheapening of the operating Ineth methods in california it is the general practice to use electric power but this has been slow of adoption on the cony rey prop property erty owing first to the belief t that hat the character of ti the ae ground presented difficulties that could be next dredge with electric machinery using a supplemental steam heating system for the colder months this third dredge is of the single lift sluice box type it was built entirely from designs made by the owners the hull is feet long by forty eight feet wide giving it probably as much if not more area than any other dredge of its kind ever mr J i emarl N 4 N A general view of the dredge nearly completed et more readily with the steam power and d second to the need of artificial heat both th fil the water and air for operation in the e winter inter months of such a severe clite which it was thought could be provided more satisfactorily and efficiently by the e condensation and radiation of a steam plant it K was decided however to equip the built it is eight feet deep and thoroughly trussed for all the known strains the ladder way or well in the center of the forward part and in which the bucket chain and ladder ladde r work up and down is 64 feet 9 inches by 7 feet 3 inches the ladder is feet from center to center 0 of f tumblers it is of br bridgework I 1 idge work construction built up of ingles angles a lattice truss and a plate bottom connecting the lower ends of the side flanges this bottom or cross plate serves the double purpose of strengthening the structure and providing a trough for some of the slop and spill of the buckets to return to the point of digging under the water the bucket chain is of the open con necked type at present with forty one buckets and forty one space links the bucket complete with manganese lip and sheet steel hood weighs 2600 pounds the space link weighs about 1400 pounds they are all fitted in the back eyes with manganese circular bushings and connected together with high carbon steel pins of 5 inch diameter the upper tumbler is 6 sided fitted with manganese wear plates and bearing on a 16 inch nickel steel shaft the center line being thirty one feet above the lower deck on this shaft is suspended the ladder so that its inclination is constantly the same as that of the chain on the ladder are twelve steel rollers 12 inches in diameter the lower tumbler is also 6 sided with face plates and flanges of manganese it is keyed to a nickel shaft 1314 IS inches in in diameter the ends of which run in a capped bearing continually filled with oil or grease the material excavated is elevated over the upper tumbler dropped onto a steel dump sheet where it enters a revolving grizzly or screen this screen is of half inch boiler plate and is 18 feet 2 inches long by 61 inches inside diameter lined throughout with manganese wear plates there are numerous openings 41 by 6 inches and 6 by 7 inches through which the smaller rocks and finer dirt pass to the sluice box underneath the grizzly is set flat but fitted with spiral angles to drive the large sizes to the discharging end where they are dropped onto inclined shoots that convey them to either side of the dredge it is also banded near each end by a heavy locomotive tire each resting on and between two manganese car wheels the shaft on one side also carries a gear which meshes into the train that is finally moved by a 10 h p type T F westinghouse induction inducil on motor the sluice on the upper deck is 28 feet 10 inches long by 62 inches wide lin edwith lined with hungarian riffles fiffles rif fles made up of angles and spring steel liners the long sluice on a separate pontoon feet is feet long and 66 inches wide also lined with similar riffles fiffles rif fles near the lower end is a set of closely spaced bars with an opening in the bottom of the sluice itself permitting a portion of the finer material to be carried into an undercurrent or auxiliary sluice 54 feet 6 inches long and 13 inches wide and lined with wood riffles fiffles of the same type the main ion long sluice is supported by an angle iron structural trussing the whole attached to the boat by a steel adjustable tongue the connection of the sluice itself being cir circular culat with a pure gum packing fitted between specially designed cast rings to prevent leak or spill the flume is swung side to side in the pond by means of three quarter inch cables attached on the pontoon to a manually operated double drum winch and to suitable anchorage on shore in the well way also is provided a set of bars through which the drippings droppings drip pings and slip pings from the bucket chain pass to another sluice box at the forward part of the dredge provided with necessary riffles fiffles rif fles the dredge is swung side to side in the pond by means of three quarter inch cables attached to one end to the forward part of the deck and leading out to a shore sheave whence they return to the dredge and connect to a reversible friction type winch propelled by a 10 h p type T F induction motor of westinghouse make the dredge is held to its work by the mooring line system this consists of a heavy framing at the rear on which sets the steel mooring head revolving on a double ball bearing and equipped with four sheaves for the lines these lines are anchored at the corners of a square about feet apart the two forward lines are 1 chesin in diameter one end being fast ened to the mooring head itself thence running out to a sheave near the anchorage and returning to pass through the mooring head sheave to a large four drum winch on the lower deck this winch is equipped with the necessary brakes friction clutches etc weighs about forty five tons in all and is operated by a 30 h p type P westinghouse motor the two stern lines are one inch in diameter and are fastened on one end to the log anchorage thence running through the mooring head to the winch when the boat is to be moved ahead after a cut has been taken out the stern lines are slacked off and the head lines pulled in the latter also serve to hold the buckets to their work and the system gives an elasticity for hard digging that is not allowed by the spud method the power for the digging is transmitted through a specially built h p type F westinghouse induction motor capable of per cent overland and a stall of pled to a 50 h p type 0 westinghouse motor one 14 inch worthington horizontal volute pump coupled to a 75 h p general electric motor the total capacity is about gallons per minute the current is alternating 60 cycle 3 phase transmitted from the power plant on the madison river thirty five miles at a voltage of then stepped down to 2200 volts for use aboard the dredge for several of the smaller motors it is then further stepped down to volts and volts for the lights the power is brought onto the dredge by means of a heavy insulated cable two inches in diameter supported across the water on a chain of small pontoons pon these latter also serve as a gangway in the pilot house are arranged the controllers tr for the various type F motors in addition to the operating levers brake wheels etc the switchboard is also there being of five marble panels equipped with e V 1 0 7 5 ap P 7 F 7 za on e buckets being fastened on the ladder of the dredge three minutes it is set on a structural strut connecting the mooring head with the bearings of ahe the upper tumbler it is pinioned to a specially designed miller slipping friction the 7 inch shaft of which is geared to a 1012 lo foot shaft carrying a pinion which meshes into the 13 foot main driving gear on the tumbler shaft this large gear is of the split hub and run type and weighs eleven tons there is also provided an auxiliary brake on the friction shaft the ladder is suspended by means of two linch l 1 inch lines working through a double tackle and connected to a marion hoist propelled by a 75 h p type IV P westinghouse induction motor equipped with magnetic brake to wash the gravel there are one 10 inch worthington horizontal volute pump coupled to a 50 h p general electric motor one 12 inch morris centrifugal pump cou necessary voltage ampere kilowatt and recording meters all of westinghouse make the dredge has a capacity of about yards per month if not more and operated continually on the three shift basis it commenced digging on sept 12 1906 the gold is fine flaky and floury and is caught by the use of quicksilver freely sprinkled in the sluices |