Mount Morgan.

Te Aroha News, Volume V, Issue 215, 13 August 1887, Page 1

Mount Morgan.

The report of Mr John Macdonald Cameron, M.J\, a mining expert, upon the Mount. Morgan Gold Mining Company's property, has just been received by the directors. Tho Queonslander publishes a resume of tho report, from which we make the following extracts :•— Mount Morgan consists of an elevated rocky mass sparsely covered with gum trees. Its height from tho bed of the Dee creek has been reckoned at about 500 ft., and above the sea level at 1225 ft. On the south side it rises somewhat precipitously, whilst on the .south-east tho ascent can be made gradually along the slope of the spur until the summit is reached. A cursory inspection of the mount leads the visitor, be he expert or tyro in geologic or mineralogic science, into a veritable quagmire of doubt and wonder as to the one or the many causes that have operated in the remote past to produce such a veritable El Dorado as even the very small amount of present exploration has verily revealed it to be. Mr Cameron thinks the condition of things at Mount Morgan will bear quite another interpretation than that of the thermal spring theory, and he cannot acquiesce in the theory entertained by Mr Wesley Hall, the general manager, and Mr Roger Lisle, the mining manager, that the gold is derived from an oxidised mundic lode, the heat of oxidisation being such as to melt even the quartz, that subsequently water from below caused what they call a chemical outburst, during which the gold was precipitated along with the material that now forms the stalactites to be found in the rugs and cavitie3 of the mine, and that as depth is gained tho ore will be found in its normal condition. Respecting the assay values and of the assays of stone from the various zones of tho mine as performed at the company's property Mr Cameron says, commencing on the western side of the sandstone dyke, a mass of stone 18ft in width yielded 4oz of gold per ton ; then comes 4ft of argille-arenaceous material that, so far, has been found quite barren ; next to this there is Ift of the iridescent quartz, yielding ooz of gold per ton ; west of this we get 20ft, yielding 3oz per ton ; and again 50ft, some of which has yielded as high aa 360z per ton ; and lastly 2oft, yielding 2^oz per ton. In what is known as No. 1 drive, and at about 45ft from the southern entrance, there are merely traces of gold, and this condition of thing 3 continues until there is encountered a vein of purple oxide of iron about 18in in width, that Mr Lisle informed him yielded 17oz of gold per ton. This vein neighbors amass of tufaceousorcintery rock, permeated by a network of narrow quartz veins, the interstices of which are filled up by small angular fragments of rocky tufa and dry ash powder. This mass of rock ha* a width, as exposed in this part of tho drive, of about 30ft, and yielded by as3ay Hoz of gold per ton. It is terminated by a tine-grained and compact dyke of igneous rock about 16ft in width. Passing this rock wecome upon another auriferous group of stone, assaying from 6dwt to 2£oz of gold per ton ; and finally the drive ends in another igneous belt of compact rock. About 200 ft from the entrance of No. 1 drive, then upward, a shaft is being constructed, and from this shaft a crosscut has been driven which takes almost a semicircular curve until it ends on the northeast side of the mount. In this crosscut there is exposed a mass of tufaceous material 136 ft in width, containing a network of quartz vein 3. Fifty tons of this material, when dry-crushed and chlorinated, yielded an average of soz of gold per ton ; whilst some samples taken indiscriminately from it assayed as high as 30 oz of gold per ton. Mr Cameron quotes the remarks as to the quality of Mount Morgan gold made by Dr Leibius, director of the Sydney Mint, and says, "If 1 except the product of the Mezquital Del Ore gold mine in the State of Lacaticas, Mexico, I have never seen gold of such extraordinary fine quality. " In part four, Mr Cameron speaks of the old and new plant methods of ore treatment and calculation of yield of gold per man, and says :— -' For some time during the earlier career of the present company the ores were treated by the usual wet crushing and amalgamation methods, but it was discovered that considerably more than one-half the contained gold was left in tho tailings. With the view of obviating this loss, investigations were set on foot that resulted in the adoption of the chlorination process, with such modifications as were suitable to the chemical nature of the ores. Chlorination barrels, with their auxiliary leaching and filtering vats, capable of treating 800 tons of ore weekly, were subsequently erected, and the process is now being worked so successfully that upwards of 98 per cent, of the gold shown by assay can be extracted. It was further discovered that, in consequence of the almost microscopic fineness of the free gold present in the ore, a very considerable amount of it was washed into the sluices by the current of water necessary to wash the ground ore from the stamp head and over the amalgamating copper plate. To obviate this, recourse has been had to dry crushing rollers, and whilst I write four sets of these are in course of erection. There is also boing erected about midway up the mount, and in close proximity to the ore-way from the tunnel, additional crushing and chlorination machinery that will crush and otherwise treat 1000 tons of ore weekly." He estimates that taking the ore to be treated as only capable of yielding the amount per ton shown by the lowest assay of samples from the southern front of the mount— namely, 2£oz of gold per ton, when both tho old and now works are treating their maximum weekly amount, there would be a yield from the old works of 800 tons of crushed ore, and from tho new works of 1000 tons, making together 1800 tons ; and these yields for a period of 52 weeks would amount to 93,600 tons, each ton yielding 2£oz, or a total of 224,0000z of gold per annum. Mount Morgan golds readily sells at £4 4s per ounce ; hence, 234 5 000ozwould yield £982,000 ptorling. "If," he says, "we deduct from this amount the cost of quarrying, carrying,

crashing 1 , and chlorinating, which when the new arrangements are completed ought not to c- ceed 40s per ton, or £156,000 for 93,600 tons, there would thus remain a net profit of £795,600, which, on the present nominal capital of the company, would be equal to about 79^ per cent, per annum. In the paddock attached to the old crushing mill there is stored an enormous quantity of auriferous stone and savel tailings. It was impossible for me either to weigh the stone or tailings, but I content myself with giving the manager's data. The former amounts to about 30,000 tons, and the latter to about 25,000 tons. It is further asserted that these 55,000 tons will yield not less than soz of gold per ton. If these data be reliable, and I have no reason to doubt they are, there now lies in close proximity to the old mino and chlorination works an amount of stone that ought to yield not lesa than £1,000,000 sterling neb At the present rate of working, about 15 months will have elapsed before the last of this ore will have passed through the chlorination barrel ; but notwithstanding this we cannot forget how quickly time passes, and what unforeseen and incalculable delays are incident, particularly to the manufacture and erection of mining machinery. Experience has shown that ore can be transported by an aerial tramway for any distance under one mile for a little over Id per ton." Mr Cameron then makes some concluding remarks with respect to the work recommended to be undertaken at the mino on the site selected for the new works ; and the abundance of wood and water ; area of the property owned by the company ; and in a final paragraph says, " The vastness of the mass even now exposed is absurdly beyond even an approximate computation ; but are we justified in thinking that this state of things will continue ? So far as my observations went, I could see no limits, though, doubtless, there is one in the same sense as there is a limit to all things, and in this connection I may again quote the Government geologist, who says, < But the amount of auriferous stone at present in sight is enormous, and there is no rashness it believing that it extends over a large area, and to a considerable depth.' With this quotation, in which I need hardly say I entirely concur, I conclude, for the present, what from a scientific as well as from a practical standpoint has been to me a most interesting, a most instructive, and a thoroughly enjoyable work."

AN IMPORTANT DISCOVERY. The Townsville Bulletin says :—": — " Quite a sensation has been caused during the week in Rockhamption mining circles by the announcement that excellent gold-bear-ing stone, assaying from Boz to soz per ton, had been discovered at a depth of 300 ft in the Mount Morgan claim. In our article on the ' Golden Mountain ' some time since, it was explained that a tunnel, known as the * Freehold Tunnel,' was penetrating the hill from east to west. This tunnel was advancing straight for the centre of the mountain, which would be reached in about 900 ft. At this spot the tunnel would have a vertical depth of 300 ft from the top of the hill. The golden stone has been found in the tunnel 360 ft from the outlet, or 640 ft distant from the centre of the hill. In all probability this 640 ft to the centre is all equally rich stone, and how far such ore will extend to tho west of the central point has not yet been discovered. This find is of immense importance, as it must quite treble the amount of stone known to be payable, and goes to show there is no diminution in the value of the stone as depth is attained."