THE GOLD DREDGING INDUSTRY.

Otago Witness, Issue 2373, 24 August 1899, Page 18

THE GOLD DREDGING INDUSTRY.

IN ITS PRACTICAL, ECONOMIC, AND GENERAL ASPECTS.

(By Our Special Commissioner.) XXIII.— NASEBY. Failing to get across Station Hill from Macraes to Hyde and catch the Naseby ; coach there, because no horse was to be had for either love or money, and for the same reason I could not get to Dunback in time to meet the up-coach to Hyde, it was necessary to retnrn to Dunedin, via Palmerston, and make for Ranfurly by the Otago Central, and thence by coach to Naseby. The next morning, therefore, at 6.40 a.m., I was at the Dunedin railway station, took my ticket for Ranfurly under the promise (advertised time table) of the Government to be delivered safe and sound at Ranfurly at 1.50 p.m. the same day. Owing to delays of one kind or another — presumably on account of a usedup engine — the train did not reach its destination until 3.10 p.m., or one hour and twenty minutes late. The distance between Dunedin and Ranfurly is 85 miles, so that the train, having beeil eight hours and ten minutes in transit, came near making ten (10) miles an hour. What was even more remarkable was that the driver ( of the Ranfurly-Naseby coach came near doing equally well, covering the nine miles in little more than an hour. It appears that the Otago Central is afflicted with slowness all round. Slow in construction, its trains are slow, and its time is late. This might be all right so far as the Government are concerned, bub what about the traveller who makes his arrangements upon the Government time table. In my case I had arranged for a conveyance to take me to Kyeburn, thence to Naseby. This falling .through meant the loss of a whole day to me, because the train was one hour and twenty minutes late. Arriving at Ranfurly at dusk, worn out by a protracted railway journey, you have to climb into an open trap, packed with passengers as a barrel is with herrings. There is a, nine-mile journey to Naseby before you. Snow had fallen thickly during the preceding night, and was lying several inches deep upon the ground. On the barren open flats were herds of cattle without shelter or cover, looking for the shrivelledup grass amongst the snow. At last Naseby was reached, when it was just light enough to note pleasantly-laid-out gardens, in which pines of several species prevailed. Their branches gracefully drooping with the weight of the snow, and standing upon rising ground, made a very effective picture. ISaseby is one of those instances of mining centres illustrating the permanence of alluvial mining in Otago. If dredging has up. to the present nob been so successful as in so many other places in Otago, it has been plainly shown that the cause is not the absence of the gold, but that it occurs under conditions that are not favourably to dredging, as will be shown presently,. The town, has in its surrouadiasc

hills, gullies, flats a wealth of aoriJeW ous wash, well suited for sluicing and elevating, that easily rivals for richness and permanence any dredging field in. New Zealand. Somewhat tardily the present Government have recognised the obligations imposed upon them as custodians of the national golden treasures of inland Otago, and £12,000 was voted for the construction of a reservoir for the conservation of storm water. The dam is a gigantic undertaking. It is to be 70ft high, and is calculated to contain when completed 600 million gallons of water. The retaining wall is 100 yards in thickness at the foot, and is sunk 20ft below the surface. It is constructed of earthwork, faced with stone. At the present time about 30ft of the embankment is finished, but work was interrupted by the late frosty weather and snow. Although only partly constructed, already 300 million gallons of water have been distributed to miners, who, but for the water, would have lost the time and gold this amount 'of the element represents, giving a slight foretaste of the promise the work holds out when completed. It is estimated that the dam in its complete form will bridge over the whole of the dry season, which may be taken at an average as' equal to two months every year. The contents of the dam when full, and after every other source or artificial supply has been exhausted, will give all the miners at present upon the field a full and regular watersupply for six weeks of 24 working hours per day. The site of the reservoir is exceptionally well chosen, and is at an elevation to distribute the water by the town, and Government water races, thus commanding the whole of the Mount Ida goldfield. This undertaking is one of the most judicious any Government has ever taken in hand. In the first place, it is a good and safe investment, and may " even be called a. profitable one, as the water will be eagerly competed for at the rate of 30a for a week of six working days of eight hours per day, which would not only mean good interest on the cost of the work, but would pay, besides the Interest, a surplus for refunding the original sum invested. In the secoud place, the increased water supply will give a corresponding increase of employment, and make mining at Mount Ida less intermittent, and consequently more remunerative, than it is at present, Avith an interruption of several months in winter, and again several months in summer with the drought. Even with the supply from the reservoir so far as ib has been constructed, the demand for water was greater than the supply, and it will ba remembered last year was an exceptionally wet one. The reservoir will fully double the present supply by the Government race, without any additional expense for maintenance of either race or reservoir. In the third place, the water, should mining ever become extinct at Mount Ida/ will come in for irrigation purposes. What the reservoir means for Naseby has been strikingly, illustrated during the past season, when the supply from the partly-finished dam made a very sensible impression upon the trade of the place, and it is fair to argue that further increase in the water supply will produce a proportionate increase in the number of miners employed, and by so much enhance commerce. The work is of such importance and magnitude as to entitle it to be looked upon, not as of local importance only, but as a work of national significance. The Nasebt Dbedging and Hydraulic Sluicing Compant (Limited). This is the first dredging venture started near Naseby, and was a success, though owing to various circumstances the dredge belonging to the company has been idle for some time. As the title implies, the company carry on sluicing as well as dredging. Owing to the great elevation of the Naseby • mines water is scarce, and therefore a valuable commodity that has to be economised. After all the water has been lifted out of the main creek for hydrauli eking, a small stream collects lower down the creek, which would not give sufficient pressure , for hydraulicking, and this the Naseby * Dredging and Hydraulic Company decided to turn to account by putting a. dredge upon " the creek. The dredge was built and has ; now been on -phe ground for about 16 months, out of which* she has worked only little better than seven months' actual working time. Ib was found after 12 months' intermit- ' tent work that the amount of golcl obtained by dredging did not at all compare' favourably with that obtained by elevating. The gold occurred on a hard, rough Maori bottom. The wash itself was very hard, and when raised it was found that the revolving screen was not adapted for saving the gold. After some of the shareholders had visited Waipori to inspect the gold-saving appliances in use there, the screen was condemned, and a box, 70ft long and 4ft wide was put in its place, and did much better Even with all this expense, the returns did not at all come up to those of the elevating process. The following statements will be read, I feel sure, with the greatest interest by all concerned in dredging, as well as by those engaged in hydraulic elevating During the last 12 months the dredge has worked 190 aays of 24 hours per day? winning £2283 worth of gold, at a cost for o°, a nV vages ' and ofcher running expenses of £1292, to which must be added £700 for repairs to the dredge. Without counting },^ T ' the P rofifc on the transaction . was £991. Adding the repairs and interest on the capital invested, there is no profit. For this amount of gold about seven acres of ground were turned over. One acre of ground worked by the hydraulic elevator was turned over in about the same time, giving £1195. To get this amount of gold it took £623 for wages, water rent,

etc., leaving a clear profit of £564 for the : acre elevated, as against £141 per acre dredged, not including anything for repairs. It may be stated that the ground dredged and that elevated was of equal value, prospecting from sgr to 6gr per cubic yard. This exposition of affairs throws a strange light upon dredging in comparison with hydraulic elevating. Although there is a way of accounting for the discrepancy in the yield of the two processes, it does not make the case any better for dredging — that is, of course, under the above unfavourable circumstances. Allowing that a certain amount of gold was lost by the box as well as by the screen of the dredge, there is something like a loss in gold of £400 per acre dredged to be accounted for, and that cannot be done in any other way than oy assuming that gold equal to that amount has been left upon the bottom, which the dredge could not get. To get this amount by working the dredged ground over again by hydraulicking would absorb fully that amount, so that, virtually, about £400 per acre of the seven acres dredged, i making a total of £2800, was irretrievably lost. ! With this very plain fact before them It is not surprising that the directors ; should decide to give up dredging and go back to hydraulicking. • When it was stated above that the dredge ; had cost £700 in repairs for seven months' work, the expense must not be charged to any fault in the dredge, its construction, or • the material. The repairs were simply ■ owing to the hard nature of the ground, as they consisted exclusively of wear and tear . upon the buckets and other running gear. Although, in point of fact, the dredge paid more than working expenses, and gave every satisfaction so far as workmanship and material is concerned, I believe I am justified in saying that the dredge, having undergone a thorough overhaul and being an first-class working order, tho directors i ihave decided not to continue dredging on I Qier present site, intending either to shift her to some eligible spot, or else dispose : of her altogether. j The dimensions of the dredge are : Pon- ' toons 70ft long by 24ft wide, depth sft, •with a well 4ft wide. The ladder is 42ft ' long, with buckets of three cubic feet capacity. The winches are after Out ten t Bros.' patent, as is also the elevator. Messrs A. and T. Burt built the pontoons, which are of hardwood framing and kauri planking, and supplied and fitted up all the machinery and gear on board, with the exception of the engine, of 12 nominal horse- < power, and the boiler, of 16 horse-power, both of which are by Ruston and Proctor. The cost of the dredge was £3250. Messrs •A. and T. Burt ran the dredge for a month, , guaranteeing all repairs that might occur for a month after her completion. The Naseby Dredging and Hydraulic Company, though a registered company, is composed of four or five principal shareholders. The above extended notice is j •made because a great deal of misconcep- ■ tion concerning the dredge and its doings lias got into circulation, reflecting upon the j company, as well as upon dredging in general and upon dredging at Naseby in particular. Besides this reason, the experience of the Naseby Dredging and Hydraulic Company is of the greatest interest to miners gener- ' ally. First, there is the fact the company proved that a dredge was capable of turning over one acre per month of actual working time, while it took the elevator nearly one year to do the same amount of work. Say that the ground worked by the elevator was twice the depth of that turned over by the dredge, the capacity of the dredge as compared with the hydraulic elevator stands as 6 to 1 in favour of the dredge. This, strangely enough, is almost equalised by the returns of the work, for we find that the ground operated upon was worth 6gr per cubic yard when worked by the elevator, and that, according to the above statements, ground of the same quality gave only l£gr as the dredging result. This exposition of the case gives a strange insight into the loss of gold in dredging operations, where the conditions of the bottom are unfavourable to the dredge bucket cutting into and removing the gold with the layer or bottom upon which it rests. The success scored by the elevator over the dredge is very easily accounted for. Very simply and .plainly it is so, because the elevator allows the bottom to be cleaned up perfectly, scarcely leaving behind a spec, and certainly not such a number of them as to affect the success or otherwise of the work. At a first glance the loss of gold by the dredge is excessive, but upon reflection it discloses most valuable information on the action of the buckets upon the wash, when dredged. In the present instance, the case is made much more remarkable by the fact, that the ground was shallow, and the chance of losing the gold was much reduced. In a high i.up,u p, where the buckets stir up the ground pi oportionately more, the sinking of the irol 1 to the bottom is much more favoured (.ban where the depth is shallow. Jn the case under consideration the depth

never exceeded lift, and fell as low as sft. The contention that in the case referred to, the condition of the bottom was a_hard and rough one, cannot affect the argument advanced — namely, that the loss of gold by dredging is much greater than is generally accepted or admitted. Perhaps with an improved water supply the Naseby Company may see their way , clear to rework the ground dredged by the : elevating process, and give the result to the public. However such a test may turn out, so far as things have gone the dredge has proved conclusively that a hard Maori bottom is most unfavourable to dredging, and the same is equally true of hard rock, all of which has long been well known ; anJ no miner, who has ever tried to lift gold-bearing wash out of water with a shovel, off even a moderately hard rough bottom, but knows the difficulty of the pi'ocess, and it is the same with the dredge bucket. But for all that the extent to _ which loss in the case of the latter is carried will be a revelation to most miners and dredgers. Another item disclosed by the Naseby Company's experience is that the revolving screen is not all powerful as a gold saver. In fact, this company is not the only one that has made that experience. Of the seven or eight dredges on Waipori, there is only one using the screen, all the other parties prefer the sluice box elongated for ' dredging purposes. What makes this the more striking is the fact that the majority of the parties are private ones, chiefly composed of old miners, and that they should prefer the box to the screen tells a tale that t 1 may well be taken heed of. Mr A. R. ' Edmonds, dredgemaster of the Jutland Flat dredge, Waipori, who has a good knowledge of gold-saving appliances and their action, has erected the most complete goldsaving plant that I saw in my tour, including a table, but no screen, and expresses himself satisfied that at least as much gold can be saved by a properly-constructed box as by the screen and tables. The screen can ; be of use only where the gravel requires I to be broken up, or where the wash is very ; clayey. The chief objection to the screen is its cost, and the cost of its transport to all places where access is difficult, and in most such localities it certainly is not worth . the cost. SPEC GULLY. This locality, at some little distance from \ Naseby, is favourably spoken of by many miners of the neighbourhood as being easy to work and rich in gold from a dredging i point of view. The depth of the ground is from 17ft to 20ft, with more or less goid from top to bottom. The wash resembles that of the Waipori and Tuapeka rivers in , nature, and is also totally different from ' that in the Naseby main gully. XXIV.— NASEBY. The Naseby dredges, it must be admitted, have not been the successes it was antici- ! paled they would be. As has already been stated the chief reasons are the shallowne«s i and the hardness of the ground. Both j these objections may, to a great extent, be •! overcome by dredges especially designed for i such conditions. What reason can there be , to try and work to make it pay, ground 6fO or sft, and even oft or 2ft deep with ladders 50ft and 45ft long. This state of things is so preposterous, that, were the thing not an actual fact of which anyone can convince himself, the person making such a statement might be looked upon as demented. It is perfectly true that all ground varies in depth, and that a dredge, placed upon any ground whatever, must be prepared to bottom the deepest i»iriimJ met with. This variation in depth, however, is limited to very trifling oscillations. It i is a well-known fact that every gold-bearing ' stream, carrying gold upon the main bottom, lias in its bedrock an even and regular fall. Occasionally there may be sudden rises, but they are exceptions so rare that they may be taken as examples that prove the rule. The same is much more the case with a false bottom. It is not necessary to go further into the matter. All that has been .said is self-evident, and how it is that dredges are not bujlt to suit the shallowness of the ground they are intended to work is one of those things " no fellah can understand." It is equally absurd to expect a ladder 20ft long to bottom ground 40ft deep, and as it is to make 4ft or sft deep ground pay with a ladder 40ft or 50ft long. It is on this rock, together with the hardness of the bottom, that most of the Naseby dredges got wrecked. Although dredging at Naseby at the present moment is under a cloud, the importance of the industry is fully recognised. A company known as The Exterfiuse Dredging Company, have just completed an up-to-date and powerful dredge to work some ground a little more than one mile from Naseby, where the company hold a one-nacie claim. The company, though floated ip Dunedin, is chiefly composed of Naseby men, which ought to be enough to prove that there are those who still have faith in the cullies

and flats of the Mount Tda goldfields as dredging ground. The ground here is much easier to work, and is deeper, carrying more ; or Ics gold from top to bottom, is about 17ft in depth, and is altogether of a different formation from that in the Main Gully at Naseby. The company, therefore, start under most favourable circumstances, ■with a fair promise of success. The dredge had just 'been completed at the- time of my visit to Naseby, and will be in full going order in a few day? 1 . A preliminary tiial made with the machinery proved that everything Arorked with perfect satisfaction. The designers of the dredge are Cutten Bros., A. and T. Burt being the builders, supplying all the machinery nr.d gear on board, with the exception of the engine and boiler, which are by Ituston and Proctor, and are of 10 h.p. and 14 h.p. respectively. The name of the dredgemaster is Mr Adair, who also acts as engineer on board. The dimensions of the boat are : Pontoons, 60ft long, by 24ft overall. Their depth is sft, the we'll being 4ft wide. The ladder measures 36ft, and is capable of dredging to a depth of 20ft, and over. The buckets arc of 3£ffc capacity. The winches are after Cutten Bros.' design, made by A. and T. Burt. The elevator is by Cossens and Black. The cost of the boat of £3500. The gold-saving apparatus is a revolving screen, 20ft long by 3ft 6in in diameter, with steel step tables. KYitfBURN. _______ The drive from Naseby to Kyeburn, I am likely to remember for a long time, were it only for the price of buggy hire and a boy to drive. The distance is about six miles. There are tivo dredges pt vovk at the Kyeburn, and a third ci.t i:-' V'ng idle some distance up stream. Ac <• <Yi",g to position and surface indications, the Kyeburn should be ideal dredging ground, and so there is proof it would be were the wash deeper. With no more than 2ft and 3ft or over sft and 6ft of gravel to work, and frequent big stones upon the bottom, which, of course, are much more frequently met with in shallow than in deep ground, for the simple reason that more ground is gone over in a given time in shallow country, the dredgemasters have anything but a rosy time of it. Other drawbacks operating against the chances of success are the price of coal, and at present the frost. Tin? Kyehurx C4old Dn edging Company. ', This company was registered in September, 1897, with a capital of £4000 in £1 shares. Actual work was started about two years ago, and a considerable quantity of ground .has been turned over since then. The ground, though fairly loose, is stony, but very shallow. The bottom is a soft Maori bottom, and were it not for this fact the dredge would have been • a most lamentable mistake, for the ground in places is only 2ft deep, and as the draught of the pontoon is rather more than 4ft, it is often necessary to scoop up the bottom to allow the dredge floating room. The dredge, T learn, was bought at a comparatively low price at Blacks, where she had been struggling for some time with j difficult ground, which proved too much for | her. She was bought by the company, who ' lost no time in transporting her to her | present site, and started work with her i about two yours ago. Up to the end of 1898, according to the published statements, the company had .spent £5041, against a gold account amounting to £1390. Since then the financial position has not been much improved, the company still being some £600 or £700 to the bad. This was the first dredge to start work upon the Kyeburn. The holding is 100 acres in extent, and measures one mile along the course of the creek. The dredge had been laid up for some time through the breaking of a shaft, which i snapped off as if cut through with a saw, ' for which the frost must be blamed. Work has been started again, and everything, but for the frost, works well. The dredge was designed by Mr E. Roberts, of Dunedin. The 10 h.p. engine and 16 h.p. boiler are by Marshall. The winches are also after Roberts's (Dunedin) patent. They are small and light, but answer their purpose very well. The pontoons are 56ft long, by 24ft over all. The ladder is 35ft long, and the buckets are 2£ft capacity. The gold-saving apparatus consists of a revolving screen and tables, furnished with matting, weighted by expanded metal, etc. Mr J. Bennet is the dredgemaster, and having had 14 years' experience in dredging the company may rest assured that their interests are well looked after, and, being evidently a man 6f a practical turn, he is the right man in the right place. He is hopeful of getting into deeper ground before long, which will of course have a salutory effect upon the returns. The present face is taken about three chains wide, | which, however, does not include the whole width of the gold run. Stones are both large and plentiful, some that cannot be brought up through the bridle of the ladder, are buried in holes excavated for them in the false bottom. The Mount Ida Gold Dredging ComI pany. This comDany. which is also a public

and registered one, has a 100-acre holding I below the Kyebifrn Company's claim. The | diedge is a new one, and started work only in September last. The returns vary with the depth of the ground — that is to say, they are better -where the ground is .deep, and have run up to 18oz per week. The ground has prospected up to 3grs per cubic yard. Here, as in the Kyeburn Company's claim, the chief trouble is the shallowness of the ground which often is only 3ft or sft in depth. Stones too cause a good deal of bother, and occur up to a ton in weight. The dredge is comparatively a cheap one, having cost £2900, which is partly accounted for by low cost of cartage, being near Eanfurly Railway Station, and the economical construction of the pontoons, which are 60ft long by 24ft over all, with a depth of 4ft 6in, the well being 4ft wide. They were built by Xnewstubb, of Port Chalmers, and are of hardwood framing and kauri planking. The ladder, which j is 36ft long, was made by the ■ New Zealand Electric and Engineering Company (Stevenson and Poole). ' The buckets, of 3£ cubic feet capacity, are by J. Sparrow. The engines, of 10 h.p.. and boiler, of 14 h.p., are by Marshall and Sons. A. and T. Burfc supplied the winches after Cutten Bros.' patent. The elevator, which has been recently fitted up, is by Cossens and Bkck. All other driving gear and machinery is by A. and T. j Burt. The plant on board the dredge -was j fitted by Knewstubb, of Port Chalmers. The • dredge is built after the designs of Cutten ; Bros. The revolving screen is 17ft long, j with a diameter of 3ft 6in, by New Zea- • land Engineering and Electrical Company (Stevenson and Poole), and with usual tables fitted up in the prevailing manner with matting, etc., forms the gold-saving apparatus. Mr Walter M'lntosh, the dredgemasler, has had to battle with many difficulties. The wash is hard and stones are frequent. To the general trouble has to be added the j frost, which has already caused the cams in the main wheel of the bucket di'ivmg-gear • to break, and also accounts for tl:e slip- | ping of the belt, the rollers freezing in the ' gudgeons. There having been much j severer frost since the time of my visit, j it is probable that work may have to be j suspended for a time. j j Mr M'lntosh has scored as high a.s 18oz per week, but about half that amount is the average output of gold, which is just sufiicient to clear working expenses. The face is taken from 3 to 4 chains wide. whi«'h is, however, not tne width o.f the gold, as- payable, prospects can be got on ' either side of the working ground, the gold j appearing to extend even 'nto the banks j on either side of the creek bed. If this ; should be t-lie case, there irf a long lease j of life before the company. = The third dredge in the Kyeburn, spoken of above as idle at present, is an ancient lelic, dating back to 1883 or thereabouts. She has been shifted quite a number of times, coming from Alexandra to the june- I lion of the Fillyburn with the Taieri River, . near the Rock and Pillar. From the Filly- i burn she was taken to the Little Kyeburn, j where, after some months' work, it was j found that the ground was too shallow to i be worked at a profit. A company has been formed to work the ground at the junction of the Fillyburn and j the Taieri. A fully up-to-date dredge of i such calibre as to reach a depth of 30ft, or if need be more, has been contracted for, the material for which is now arriving upon the ground, so that it may be anticipated the dredge will be at work some time during the next autumn months. Before closing with the Kyeburn a word may be added on working shallow ground. That the parties concerned in placing | dredges upon such shallow ground as that I at the Kyeburn did so under a great risk j is plain, but it is less easy to understand how it was that they did not proportion the ladder to the depth of the ground. It may not yet be too late to put on a shorter ladder, which would work the ground to far better advantage than the present long one, and do so at a great reduction in fuel and ; wear and tear of machinery. In any case, j the mistakes made must be held up and , serve as a lesson for the future, so that they ( may not be repeated. • j