BRITISHCOLUMBIA DEPARTMENT OF MINES HamHERBERT ANSCOMB, Minister JOHN F. WALKER, Deputy Mini:;teer " BULLETINNo. 15 " Hydraulic Mining Methods Compiled by STUART S. HOLLAND ,194:2 This Bulletin is in large parta reprint from United States Bureau of Mines Information Circular 6787 VICTORIA. R.C. : Pho-offset by CHARL~SF. BANPI~LD.Printer to the King's Most Excellent Majesty. 1042. Page EXTRACTING GOLD FROPIAMALGAM ....................... :........................................ :...................................................................................... 58 Heating ............................................................................................................................................................................................................................................ 68 Retortiag ................................................................................................................................................................................................................................. 69 S E P A R A T IO N OF PLATINUM~GROWSEPARATION OF i%ETALS PROM GOLD 73 BIBLIOGRAPRY 75 . ii . ILLUSTRATIONS- Page Figure 1 Diagram for solvingKutter formula to determineflow of water in open channels or pipes ............................................................................................................................................................................... 10 Figure 2 Weir for smallstream ....................................................................................................................... 16 Figure 3 Flume for hydraulic mines. ." .............................................. :.............................................. 20 Figure 4 Air vent for pipe-lines. ............................................................................................................ 24 Figure 5 Chart showing loss of head in pipesdue to friction. ................................................................................................................................................................. 2% Figure 6 Ilydraulicelevator. .................................................................................................................................. 33 S luice-box construction. 41 construction.Figure 7 Sluice-box Figure 8 Types of riffles. .......................................................................................................................................... 50 Figure 9 Ap?aratus for retorting amalgamand quicksilver. ............................................................................................................................................................... 70 PHOTOGRAPHS- Facingpage Plate I A. A storage dam at the outlet of Germansen Lake 6 B. A diversion dam on the ditch-line of German:;en VenturesLtd. .............................................................................................................................................................. 6 Plate11 A. A flumebuilt on a trestleacross a steepslide. 7 B. Control gates at the end of the ditch at th,a intake to ,the penstock at Bullion Mine. ........................................... 7 Plate I11 A. A baffle box to check the water velocity at thebottom of section of flume having a steep grade. ....................................................................................................................................................................... 26 B. A section of 24-inchpipe-line leading from the penstock at CaribooCottonwood Placers Ltd ............................................................................................................................................................................................................ 26 Fa cingpage Plate IV A. The pressure box at the Bullion Mine. .............................. 27 B. Part of the main30-inch section of the Bullionpipe-line showing the founda- tion -supports........................................................................................................................................ 27 Plate V A. A No. 1 giant at a small, operation. .......~ 34 B. A No. 7 giant and a No. 4 in the No. 1 pit ofGermansen Ventures Ltd. ........................................................................................................................................................... J.................... 34 Plate VI A. Two giantssweeping gravel in a hydraulic pit. .............................................................................................................................................................................. ...... 35 B. A'hydraulic pit withone giant feeding gravel to a shortlength of sluice- boxesand a secondmonitor stacking thecoarse gravel at the end of the ' boxes ........................................... :.................................................................................................................... :.......... 35 Plate VI1 A. The No. 1 pit at Germansen Ventures Ltd., Germansen Creek, B. C. 36 B. The Bullion'pit, on thesouth fork of the n Quesnel River. ..................... :................................................................................................................ 30 Plate VI11 A. Boulder-clayshowing the irregular assenblage of boulders in a compact clay matrix. ................................................................................................................................................. 37 B. A cave at the headof a hydraulic pit showing the large masses into which the boulde r-clay breaks. boulder-clay 37 Plate IX A. Wood block riffles in a small sluice- flume. .................................................................................................................................................... :...................... 48 ~.. B. A largesluice-box paved with. wood blocks wedged together byblocks in the interstices ................................................................................................................................. 48 Plate 'X A. A 3-footsluice-box showing the load ofgravel and boulders dropped when the water was turned off. ............................... :......................................................................... 49 - iv - \ Facingpage Plate X B.- A 30-inchsluice-flume showing a central groove worn in the wood block rj-ffles after considerable service. ................................................................ ....... 49 Plate XI A. The &footsiuice-fiurne at the Bullion Mine pavedwith rai.1 riffles ................................................................... 52 B. Cross-section of the Bullion type rails ................. 52 Piate XI1 A. Looseningup the sand and gravel packed betweenblock riff1.e~. ................................................................................................ 53 ' B. Undercurrent tables at the end of the sluice at Cariboo Cottonwood Placers Ltd. :................. 53 Plate XI11 A. The endof a sluice-flumeshowing longitudinal andt:ransverse rail riffles followed by anunder- 'current grizzly niade from3-inch shafting,then a shortsection of transverse rail riffles at the end - rjf the box. ........................................................................................................................ 56 B. Handlingboulders in a hydraulic pit with a gin-poleand a handwinch at Harvey CreekMines Ltd. on Nigger(Pine) Creek .................. 56 Plate XIV A. Drilling a iarge boulder with a Jack- hammer in the hydraulic pit at Spanish Creek ............................................................................................................................................................................. 57 B. Block riffles at the head of the siuice- box lifted preparatory to making a clean- up. ......................................................................................................................................................................................... 57 Plate XV A. Clean-up at Germansen VenturesLtd ........................................ 60 B. Cieaning up the goid in 'the 'bottom of a sluice-box to remove as much black sand as possiblebefore scooping up the gold into a pan. .................................................................................................................................. 60 Plate XVI A. Cleaning bed-rock by hand .................................... :................................................ 61 B. Retorting amalgam from the clean-up barrelover a blacksnith'sforge ............: 61 -v- When placergold was first d.iscoveredin British (Columbia much of the gravel was mined'bymethods other than hydraulicking. Subsequently,however, with the working out of rich shnllow .Z;rav- el, extensiveyardages of lower grad.e gravel were left which under favourableconditions were minedby hydraulicking. Th.is typeof rniningproduces the largest proportion of placer gold :at $resent. Placergold was discovered j.n theProvince at ar ,earlydate so tht in the well known distriots most of thecreeks have been prospectedand worked wherever possible, leaving the mre unde- sirable and lower gradeground for subsequentminers. 611 the rich ground that is known has been, or is being,worked. In the Sast,failure to sample and properly estirnate the available yard- age of placer deposits has resulted in a tremendouswa,ste of money and effort. k largeproportion of placer operations have failedbecause the gold in the gravel was insufficient