SAVING FINE GOLD

Otago Daily Times, Issue 215, 28 August 1862, Page 6

SAVING FINE GOLD

We talte the following remarks, respecting the - spring of gol i, from a letter,' by Mr. Carpenter, 1 wJiWb appeared in the Argus.— -'.'lt is admitted by j all who have had experience in the reduction of t quartz that gold is lost. But the question that arises I is, Whnt are tlie causes of the loss 1 They are thrse, " and are threefold :—lst. If the quartz b not reduced fine enongh to disintegrate it from the gold. 2nd. t It' the means adopted for saving the gold will not ' a-rest the escape of the fine or attenuated particl 8 which the wakr holds in su."3])ension, 3rd. The gold I contained in the sraenical and sulphurous pyrites, ! which cannot be extracted from the latter by "either washing or amalgamation. Various processes have been. ti ied, both at home and abroad, with a view of doing away with the us; nf quicksilver, but none have been f uud tosuccied. Tin ore U disseminated throughcit the gu gu.^ it :'s assccta'ed with in a very minute elate of division. It is obtained, after the proc- bj of stamping (the tin stuff "in Cornwall is crushed much finer than any of our quartz), by a series of washing; and ere a great deal of it is fit for th« «ui'king furnace, it has to be deprived of some uuneral» similar to ours — arsenical' pv rites, called mundic by the miners —which is dona b.v roasting them by a reverheratory or calcining fuiiu.ee. I have^ alluded thus briefly to the treatment of tin ore, in onltr to show that the same means ail >ptcd to separate it from its matrice may be sac-ce-^itaUy employed for the purpo-e of saving go!d, or uj rd f specially in obtaining and preparing the subBt uicea the latter is associated with for the process of nii.alganiation. Being desirous ofinakitg myself un-di-j>tood a** well as p >*«Kible, I cannot do better than d«.s-;ril<e t'ne method which, if adopted, would ensure tb,- extraction of a great amount of gold that is being lot. We will commence with a parcel of quartz wjghing KKJ tons, which v.c will suppose eontans 1 ton of pyrites, the latter containing some 25 ounces ol god. Firstly, the quartz must be r-jduc dto that »t:oe of division which wiil ensure the disintegration of all the pyrites. Secondly, the pyrites must be 4e;>arated from the quartz by wa hing by a proper contrivance. This can be readily effected, as the bj «"aic gravity of the pyrites w so much g: ater than that of the quartz. Th'udiy, the p> ritesi being separated from the quartz, the next htep will hi to deprive them of the tulj hur and ai-vc-ni'; which enveloj>e t!u gold. Tiii* is done by pricing about tea cwt. of the p.rites iv a revebera-to-y furnace, when the charge must be kept well >t*.rre J, K> a* to be aiwavs ex pacing fr<^*h surfkees to ti. • action of the hett, which at Hrht should not exe< jd a dark red c«k>r; when the charge cea*es to ti.rowr oil' • ens t volume* of vajior, the heat can be iaciwsvd t-> a bright rtd color; and as hoon as the Uitiu-H rei-e to I*- dsi-a^m able, t'uc charge in finished h'.A ran I* withdrawn, if jt ha* beea we!l aJtendt?! to it will t*r in v Cuu: s'ati of oivUion ; if the routrarv it will U« in cake*; tbea- mint be reiuced to a l« w.ler, and agaiu submiited to tlie eddning proe .i J'V.iirthly, the pyrites c-n In- placwl in the b.,.-rtl with quicksilver, t> be umalgumated. The b.-ireUii nude to revolve about cigliteen revolutions \,i t minut *, and continue d-»iug w> fjr tome eighteen ii'in*; tlic coatciit* ut th-j barrel to Ihj kept in a th-ckihh iquil, a,j a* Vt ensure tbeir bv-I ig ti: night well into contact wiih tiw mercury, emm beam taken to k«tp the latter u> ithr. 1 a>a well aw,irv tiu»t Mmieof the pr.jc<.t>ii»:s I i aye dt-*. riled utk in ut>e, but I rt-^rtt to fctate they ar-in g.n*rat very imjic-rf. tt'y und^rstool. I have at vaxiuu*. times made num-rous experiments with •ju iriz Uti> in*."« l and 1 frar w**ie 1 to give publicity to M<;.it; of the rrHulu they w».uld scarcely t>e *.T»-dlte<l. | As the on-2 lam abjut to give cm be corrob >ratMl by i'i-jfehAor Tiiiuy, i,( G'.n-zon', 1 liave no hesitation in iri'iUKit. The owiiit of ttie *arg«-st crushing will in tL< Ikti'liio .i'w.rict bnmg.-rt t«e some tarliiiffs to tost. In t:i«ii<as/ 1 iun>l. •aiioiib^.-.-ifisay; :.f»ww.trJ» »e»ting il\. accuracy of* thov. : a>■ tv.s by'mixiug the wioui -•ai ijifci tn-.'t i\i-T, an I bikini; an averajie one : the re- ?•■{' »f my • .tp rim. :,l i,, Uu'v cisc showed a yield of 'At/., lhiv. ■>. to the : tu. It i> inipws.<ib!e tliat th«; r.-ij.itfd^l f.m find a tiner field fjr the inve-itment for hi iii«ti»-\ ibrtn in n>iiiiu«r. or in the ?xlp.*-\'v><\ of g'>! i from the t w'i'eh now iie about H*-i» mmv h*-. 4 ps of ri! .bi»ii. V/ithia the List f.-w yearn at ioue, ■\\\ the rtlu^.- sui'i tli-brut from the old uiines, thai had Mia King ;ilx>ut like kj much worthies matter fur ii.! Ny yrai-.-. Ixtfurr, }i.%h b-?en worke^J over aad leave 'ri—e ppifira.