LAMONTE'S SMELTING FURNACES.

Te Aroha News, Volume III, Issue 119, 12 September 1885, Page 7

LAMONTE'S SMELTING FURNACES.

The following information respecting the above, as furnished by Mr H. A Gordon, Inspecting Engineer Mines De partment, New Zealand, in his report on the various machinery at work ia Victoria and New South Wales for th< treatment of ores, will be read with interest : — " The Probert furnacV is made on the same principle as the Pacific, only it is? made in several segments, and instead of the water-jacket being closed at the top it is open, thus allowing the steam that is generated by the heating of the water in the jacket to escape freely, The furnace that is erected here is circular in form, but the new furnaces that are now being ma le by the Mort's Dock Company at Sydney, are oval-shaped, like the Pacific. The reason for vhis is that, in a large circular furnace the tuyeres for the blast have to project beyond the inner edge of the furnace, and thus beco*nes more liable to get burnt or damaged. There is likewise a slight difference in the circular iron flue, which, in this patent, projects horizontally irom the top of the furnace into the chimney, having condensing chambers or recesses and down-oasts to collect the oxides, which goes away in fumes. This flue differs from the flues in the new furnaces which the Mort's Dock Company are constructing, the flues in the new furnaces being below the opening where the ore and charcoal are fed from the mixing floor. The lead well or bath at the bottom of thj furnace is capable of holding about five tons of molten metal, and the quantity of ore that the furnace is capable of smelling was expected to l>e 60 tons per day. However, Mr Hurley informed me that 25 tons was as much as it hud averaged since it had been at work. " It may be well to state that in order to establish the superiority of this furnace Messrs LaMonteanH Kahlo enteied into an agreement with this company to erect one of their furnaces and work it for three months continuously, giving a guarantee that it would smelt GO tons of ore per day and save 90 per cent of metals found by assay, before being paid for it. They have, therefore, an independent manager, Mr Steams, fio.n America, who is conducting the smelting and refining operations, and if the results are equal to the guarantee, at the end of the period agreed on the company will take over the whole plant. I subsequently learned that the furnace has given evny satisfaction, with the exception *-hat it does not smelt the quantity of ore as guaranteed ; but this was owing to t! c water-jacket being too Bhort ; but they were supplying a longer one of the same length as all 0 their new furnaces are now made, and there is every reason to believe thatj whon this new jacket ia fixed anil other improvements ina<h', it will do the work guaranteed. I was likewise informed that this process gave about from 95 to 96 per cent of the metals ns per assay, which is satisfactory. The cost of the LaMoiite fttrnaces, -rea<ly to attach ,all connectioi.s with blast an.i wate'r-pipi>s ; in Sydney i 9 about £750 for a furnace that will smelt '25 tons of ore per day, and £9 0 for dne that will smolt 45 tons } b- 1 if the, whole of the machinery be inclu ed f >r the, latter S'^ml , furnace it will c<efc from £4000 to, £5000:' " The refining wbrks consisVof , r«ve»'« beratoiy furnaces,' in. which are- placed; large '\ ypels,^ himn|> eWUroh* pkefeiV .fiauioc : filled rujiYi'wi fcb : ,;,;UMtJfyuk : *s£&

bars of tutttoliriiur.llfflT^UKiltiug funmco are put mto 1 the cupels uh I roasf.vl until all the lead ah I bnsi> nytids arc oxidised. •»nd i)iithiii£r i.ut iUo jjrpdi^nft -net d loft. The fntnos from tln'Se furnaces pass through, a flue, ,\vn<M % <"k" k a squall jVt of sfuam is insisted, 'At the junction witli l!ie chimn -v, which <i«'»nd uim-s tiie i'uuius •mil causes the load to bi» deposit^ in the bottom of tho chiuiuVy as litharge. When sufficient roasting lias been done which takes about four hours 60 loxidizp all the base metals, there is a hole bored with a brace and bit from bolow into the bottom of the boned ust cupel until nearly through. Afterwards a trolly with moulds placed on the top is run in below the cupel, and the hole, pai tly bored, is then tapped with a rod punch, and the precious metal ran into ingots fit for market. " The minimum cost of the smelting process up to the time I visited these works was a trifle over £2 per ton with the Probert furnace, and between £2 and £3 with the Pacific It must, ho.r«ver, be remembered that this is the lowest cost for any week that the furnaces were at work, the maximum cost being nearly £4 per ton. The difference iv cost appears to be thai the Probert furnace is larger, consequently smelts more ore, and only requires about the same number of men to work it. However, Mr Hurley contemplatos, when all the improvements he is now making to the Pacific are completed, he will be able to treat the ore for about £2 per ton. This company has smelted about & tons Cfcwt of silver from the commsneement of the year to the 20th of March, the ore averaging 45ozs par ton.