MINES DEPARTMENT.

New Zealand Herald, Volume XXXII, Issue 9927, 17 September 1895, Page 6

MINES DEPARTMENT.

MR. GORDON'S ANNUAL REPORT. The annual report of the Department of Mines on the goldfields of New Zealand for the year ending 1894-5, made by Mr. H. A. Gordon, F.G.S., which is now to hand, is a voluminous document, and at the same time most complete, containing close upon 300 pages of printed matter, and being freely illustrated with sketch maps and drawings of various types of improved . gold-saving machinery. The subjects are classified under the following 1 heads : —" Subsidised ■ Roads and Tracks," " Roads Constructed by Direct Grants," "Prospecting Works," " Schools of Mines," •'Water-races," Gold Mining," Quartz Workings," " Alluvial Mining, including Hydraulic Sluicing and Dredging," " Explbrations in the Urewera Country," " Coal Mining, including the Origin of Coal Formations,"" The Cyanide Process ; of Treatment in Connection with Gold Saving," " Experiments by W. Skey in the Solvent Properties ot Ores in Cyanide Solutions," " Patents Applied for in Connection -with Gold Mining," ." Petroleum, " " Cinnabar Deposits," "Examination Papers recently used in Mine Managers' Examinations," and "Statistical Tables • showing the Class and Value of Works Constructed." It would of course be impossible to deal at length with any of these subjects in the columns ot a newspaper. * All that can be done is to glance briefly at some of the more important to this particular locality. " FINANCE. The statements of account chow that the expenditure for the construction of roads and tracks for the year ending 31st March, for the Auckland goldfields, was £914 7s 4d, the liabilities on authorities being £1801 0s lid. The expenditure for roads constructed from direct grants was £4137 19s 4d, liabilities on authorities being £6652 2s' sd. The expenditure and liabilities on authorities issued in subsidies to prospecting associations and parties of miners, recommended by the local bodies wer? expenditure £890 12s 9d, and liabilities on authorities £1538 12s 7d. THAMES SCHOOL OF MINES. As to the Thames School of Mines the report goes on tostate —" Notwithstanding the great depression there has been in mining in the Thames district last year, and the decrease of the number of men employed in the mines, the attendance at the school has been, on the whole, satisfactory, the average number of registered students last year being 35, in lieu of 40 for the previous year. The total number of individuals attending the school and science classes were, however, considerably less last year than for the previous one, the average number being 68, whereas for the former year there were 90. Mr. Park, however, states that for the present year 35 students had been registered for the first time, of which a large proportion has come from different parts of the Auckland district beyond the limits of the Thames goldfiold. This shows that the teaching at this institution is appreciated by those residing at a distance, as well as by the residents of the place." The report of Mr. James Park, the director of the school, which is embodied in Mr. Gordon's report, points out As an encouraging and pleasing feature of the past year, the large number of senior students who obtained remunerative employment in different capacities connected with mining and metallurgy; indeed, so much was this the case, thst at the end of 1894 he had not a single certificated senior student available for employment in response to battery owners requiring competent men. As showing the confidence which the mining community reposes in Thames students, of the fifteen cyanide plants in operation in New Zealand, no less than nine are in charge of his late students, and in most of the others Thames students were employed as metallurgical assayers and assistants. WORKING TESTS. A considerable number of working tests, treated at the school, are given. Of these, the following are some of the most important Monowai: Four separate parcels of ore were treated. No. 1 give 3oz Odwt 12grs of gold, and '28oz 14dwts 17grs of silver to the ton, value £14 5s per ton; No. 2 gave loz 2dwts 16grs gold, and 9oz 9dwts lgr silver to the ton, value £5 5s per ton ; No. 3 gave 12dwts 14grs gold, and 6oz 16dwts 3grs silver to the ton, value £3 0s 7d per ton; No. 4 gave loz sdwts 4grs gold, and 13oz 19dwt 18gr silver per ton, value £6 la 6d per ton, the extraction in each case being respectively 87, 84, 72, and 68 per cent. 'A ton of ore from the Hit or Miss, Furiri, showed a total value of ore as follows: —15oz2dwt llgr gold, 13oz 13dwt llgr silver, total value per-ton £61 15s, the percentage of recovery being'94'7. A-parcel of ore from the Broken Hill mine showed an average value of loz ldwt gold and lloz7dwt22gr silver to the ton, the value being £5 6s 2d per ton, the percentage of recovery boiug an average of 76 per cent., "a very satisfactory result." A parcel sent by Fisher Bros., of Punga Flat, Thames, showed Boz Odwt 4gr gold and soz 16dwt 3<*r silver per ton, value £32 12s per ton. Halt-a-ton of pulverised ore from the Grace Darling showed the following assay value 6dwt 7gr gold and 3oz lldwt 15gr silver, total value £1 10s 6d per ton ; a second pared showed 15dwt 3gr gold aud 3oz lldwt 15gr silver to the ton. value £3 5s lOd per ton. From the St. Hippo a parcel showed 2oz 15dwts 10 grs gold and 3oz 6dwts 12grs silver per ton, or £11 5s 9d value per ton, this was reported to be a most valuable ore, and the test showed that its bullion contents could be most successfully treated by the cyanide process. From the Alpha mine the assay was loz 15dwts 7grs gold and 19oz Sdwts 4grs silver per ton, value £9 per ton, a second Tot for the same mine showing value £9 3s per ton. ($' ' THE UREWERA COUNTRY.

Having dealt with the operations of the year in the various districts, which have been dealt with in the report of the Minister of Mines already published, Mr. Gordon goes on to deal with the Urewera. Country, of which a geological sketch map is published. The account of the tour made through the country is very interesting, but little is said as to there being prospects of gold in any large quantities. POTASSIUM-CYANIDE SOLUTIONS. Considerable space is devoted to the subject of extraction of gold and silver from ores by potassium-cyanide solution, 'and Mr. Gordon observes: — The attention of men in all the mining countries in the world has been given to this solvent, and especially South Africa, where the gold found there in the auriferous conglomerate is in a very finely divided state, and particularly well suited for extraction by this means. The gold obtained from the auriferous lodes in South Africa is not taken from the quartz, but is found in a free state, cemented to the small pebbles of quartz, which now form as hard a substance as if they were all in one solid body. The cyanide-potassium solvent ha,3 been very successful in treating ores found at Kuaotunu and in the Ohinemuri district, by reason of gold being found there in such a minute form. If the gold were in coarse particles in the stone it would have to be pounded into a fine dust before the cyanide treatment would be successful; and even in the ores found at Ohinemuri, where the gold is in a specially fine divided state, some of the particles are so coarse that the cyanide does not dissolve them in the time allowed for treatment. Hitherto experiments for improving the cyanide process nave been practically stopped, owing to the fact that the Cassel Company possessed patent rights for the use of cyanide in all its compounds for the treatment of auriferous and argentiferous ores found in any part of the colony. There was no benefit accruing to any one making experiments with a view of ascertaining the possibility of making improvements in connection with this process, as such improvements were of no direct benefit to the person making them, the Cassel Company still claiming the royalty." Mr. Gordon commends the pamphlets published by Mr. J. S. Maclaurm, of the Auckland Unversity College, to anyone using the process, and an elaborate report on the experiments made by Mr. W. Skey, analytical chemist, Colonial Laboratory, is annexed. A paper is also given on electrical precipitation from cyauide solution with plans of the plant used for the process in Transvaal mines. COAL. In respect to coal, Mr. Gordon reports as to the work done in developing the coal fields of the colony. Speaking of the coal deposits in the North he says th'ere is no doubt, when once the Waikato is in direct communication with the Thames Valley, ; that the output of coal in the Waikato mines will be greatly increased, for although the coal is inferior to that in mines further north, it will be landed at such a price that 3 mining companies can afford to use a larger quantity of this class of coal, which pro-' bably will make it more economical than using a better class at a higher rate. The remainder of the report is devoted to descriptions, specifications, and plans of patents for mining machinery, granted ; examination papers, and matter of debate, etC. v-mmmmm—mm-mmmmm—mmmm