Te Aroha Silver and Gold Mining Company, Limited. THE REDUCTION WORKS.

Te Aroha News, Volume VII, Issue 418, 9 November 1889, Page 2

Te Aroha Silver and Gold Mining Company, Limited. THE REDUCTION WORKS.

The establishment of the above works ia a matter of great importance to the whole of New Zealand, and in this aiticlo. we purpo-e giving 'a general description of: the works, and the processes in operation thereat, written in a style as far as possible devoid of all technicalities ; believing such will bo perused with very great interest by many of: our readers, both, far and near. Of course in this article it will be necessary to omit many details r both with respect to the various minesowned by the Company, and the reduction works, as these have already appeared from time to timo in our mining repoits, and to repeat such now would take up far too mufh space. Our object at the present time is to give a general, rather than a particularised, description of the reduction works. The quartz is conveyed in trucks from the mines by branch lines to tho ground tramway (constructed by Piako County Council, largely subsidised bv Government, at a 'co'.t of over £20,000), which extends up the Hill fora distance of about three miles, having three very steep selfacting grades. The ore whon it arrives at the b-ttery platform is discharged direct fiom the bucks on to ''grizzlies " or gratings ; the* bars of which are fixed two inches apart, and all ore sufficiently snvill d-ojn tlu'ouuh the grating into h"ppprs, and is fed from thence direct into the stamper boxes, l>y means of automatic self-feeding machine 1-',1 -', known as the ' Challenge.' The course ore pusses down over the i>r.itings re f fried to on to the ro< k bre ikcr p'atfonn,nt>d i« then fed direct into (he rock breakers (thiee in number, nil ' Blake's-* pitenl), and as it is discharged from these rnck breaker* i.s eonvoyud by shoots into tha Challenge ore fcedouito tho The rock breakers arc diivun from a line shift by means of an independent Pdlton water wheel of thiity horse power, and are capab'e of breaking fifty tons of quaitz each per day o!" twenty-four hours. The stamper^ are sixty in number, Foitv, constructed on the old principle generally in vogue in the batteiies throughout the Ilauraki goidfitild, weie erected several years ago, long before the present owners purchased tho property. Each of these stamps weighs about 8501b, and in working has a diop of about 10 inches, and are generally run at a speed of about 65 strokes per minute ; and are capable of reducing: about forty tons per diem (i.e. averaging about one ton to each stamper). The new 20 head of stampers are constructed on a greatly improved principle, and include a moi tar, patented in America by Mr Ho well, the Company's Manager ; also weigh about each 8501 bs, with a drop of 7£ inches, but are run at a much higher speed, viz.* 95 strokes per minute ; and are capable of satisfactorily reducing as much as fifty tons of quartz per diem (i.e. about 2^ tons each). These s f ampers are furnished with steel 'cams,' and Steel 'tappets' (or discs), and in the manner of construction are an immense improvement on the old style. By a very ingenious arrangement any one of these stampers, or any desired number of them, can be hung up without altering the speed in an} way or stopping the battery. This alone is a very gieat advantage, as with the old stampers, if it is debired to hang anj- one or more of them up it is necessary that the Battery be first slowed down, and even then it requires two men: to hang them up ; whereas, n boy with a piece of stick, made for the purpose, can connect or disconnect any one or more of the new twenty head of stampers with ease. The stampers are driven by two Pelton water wheels, of fifty horse power each ; one for each thirty head of stampers. Tho pounded quartz as it is forced through the gratings of tho stamper boxes passes directly over quicksilver copper plates ; upon which most of the free gold is retained, whilst the coarser particles, and all the sulphides contiining either gold or silver, escaping over these copper plates^ are conveyed direct to the concentrators, through iron pipes by means of a current of water. The gold and silver caught on the copperplates is cleaned up at intervals and Jreutcd in the ordinary way. The concentrators (twenty in number, viz., twelve for use in connection with the forty old style stampers, and eight for the twenty new stampers) are all of the kind known as the Frue's Patent Concentrators (or Vanners, as they are commonly called, owing to their peculiar side motion). These concentrators perform a most important work, viz., the separation of all base sulphides from the valueless quartz; and 'ganguo,' or earthy substances; nnd this result is attained by me-ins of: a simple and yet most ingenious arrangement, whereby the required motion, etc., is provided. The quartz being concentrated pusses over endless india rubber belts about 3£ feet wide and 28ft. long, revolving at an inclination of about 8 inches, and travelling round