THE GOLD DREDGING INDUSTRY.

Otago Witness, Issue 2368, 20 July 1899, Page 20

THE GOLD DREDGING INDUSTRY.

IN ITS PRACTICAL, ECONOMIC,

AND GENERAL ASPECTS.

(By Our Special Commissioner.) VIII.— THE MOLYNEUX RIVER. The. Earnscleugh No. 2 Dredge.

This company occupies the premier position amongst the dredging companies in Otago in so far as the possession of the most powerful and capacious dredge is concerned. The whole of the machinery works with a smoothness and precision rarely attained by dredges heaved, as they continually are, by the swell and fall of the current. The strain on the steel ropes reacting upon the winches fastened to the deck wrench and tug at the huge machine in a manner trying to its every nerve and fibre. The spider and the prey in its web is a poor illustration of a £3.0,000 fabric held captive by three or four steel wire ropes, not thicker than a man's finger, floating and surging upon a current like the Molyneux. THen there are the motions of moving machinery, hauling and pulling a constant load of 40 tons or upwards. The buckets, gripping a stone at the bottom of the paddock, causes a sudden lurch of the boat and as sudden a rise, keeping time and time with the rattle and clatter of cog wheels and levers, and yet with all the boat under your feet, though anything but steady, is firm and solid, inspiring the feeling of perfect safety, and after a little while of confidence.

The following details will convey something like, a faint notion of the strength evolved by the machinery put to good purpose for wresting from the Molyneux tile golden wealth so keenly coveted. The pontoons are 120 ft long,- and jbhe dredge measures 34ft over all. Upon the deck room thus afforded there are > placed engines of the latest design, fitted with all the up-to-date innovations, securing, the safety of the floating property and driving the ponderous parts of the mechanism. The engines work up to 112 indicated horsepower. What is the work required to move the buckets alone will be seen when it is stated that every set of Ihe connecting links weighs 3cwt. There arc 37 such links. This gives lllcwt. Then there are 37 buckets at Bcwt each, which is equal to 20 tons of travelling gear, that, is with empty buckets. When the bucket* are full this will be. more than doubled. This weight of 40 or 50 tons is kept going day and night at the rate of delivering 12 buckets per minute, every bucket containing 6^ cubic feet, which gives more than three tons of golden wash raised every minute, or 1440 tons per shift of eight hours, giving 4520 tons per day.

This quantity of wash is treated in two revolving screens, passing the sand and gold to tables having a superficial area of 520 square feet. The shaft working the buckets is driven by a Hotch leather belt 15in in width. The ladder is 65ft long, and can reach to a depth of 40ft. There is a 12in Tangye pump for supplying the two cylinders and tables with water. Two boilers placed side by side supply the motive power. The tailings elevator is capable of stacking the tailings 40ft high. The winches are fully up to date, and have special arrangements for starting. They are driven by a special engine, and give every satisfaction in the working of the boat.

The Earnscleugh No. 2 is also working ground which at one time was river bank and a cultivated farm, the loam having been removed by the same flood and in the same manner as in the case of the Alexandra or Chicago Company. The claim being a beach and river claim, the manager, Mr H. Downie, works the beach in the. summer and the river in the winter. Mr Downie, who is a qualified engineer, has proved himself a circumspect and energetic dredge master, and is assisted by Mr T. Wilson, late engineer in the employ 'of the Union Steam Ship Company. The whole of the ponderous machinery is so perfect in its construction that two men per shift are sufficient to keep the whole in going order day and night.

The company is a private one, and though the manager admits having done very well, and is still on good gold, nothing as to the gross yield was allowed to leak out. Parties who may be credited with knowing something about the inner concerns of the company estimate that the dredge must have averaged a handsome weekly return from their venture, the exact an'ount of which, is however not ascertainable.

The Earnsclettgh No. 1.

This dredge which, at the time it was builfc, was one of the wonders of the day, is now hopelessly out of the running, belongs to the same private party, and is well knowa to have got a power of gold in her day. The dredge also* worked wliat

was once dry land, and has turned over from 10 to 15 acres of ground, dredging to a depth of 22ft, and stacking up the tailings from 10ft to 15ft above the water level. The buckets are not more than 2| cubic feet in contents, and the machinery is long since out of date. The dredge at the time I was on board was undergoing a thorough overhauling. Boiler and machinery were all subjected to a searching investigation, a number of men being engaged in the work of renovation.

The Earnscleugh Company, which has been in existence for a number of years, is known to have obtained a considerable quantity of gold, and though they have extended the boundaries of their property further into the bank, would have, independant of that, many years of work before them. The measure of their success is, perhaps, best gauged by the new boat — that is, the Earnscleugh No. 2 dredge — placed upon the claim, which has cost fully £10,000. Such a step being taken by a. private party without calling in the aid of outside money shows the confidence the party have in their claim. Besides Uus there are many other evidences pointing to the output of the claim as being above the average of Alexandra returns even.

The most wonderful part of the story is that a great deal of the ground lifted had been gone over by dredges in times past, and payable gold extracted from it. The width of the ground worked, that is measuring at right angles across the course o? the river is 300 ft. It may be accepted as quite reliable that the ground turned over by the Earnscleugh dredges Nos. 1 and 2 will- pay to work again, in fact the real queiy being how many times over again ?

Messrs Downie and Wilson also hold the position as engineers on board the Earnscleugh Dredge No. 1, and it is under their supervision that the renovations upon No. 1 dredge are carried on.

General.

In the preceding article I had something to say on double and treble banking claims and the coining storm. That the storm has come and is about to burst there is plenty of evidence. My visit to the dredging centres fell in with the time when the monthly Warden's Courts are held. On his last circuit, ending at Roxburgh last Thursday, Mr Warden McCarthy granted in round numbers 100 dredging claims situated in the basin o'i the Molyneux and its tributaries. The whole of this, host of golden lures and promise is to be let loose upon the public, the few private concerns amongst them do not count for anything. This statement in itself should be 'enough to make intending investors pause before thej- select their particular "love." There is in this host a number of perfectly legitimate ventures holding out promises of success with more than average mining cer-. tainty, which, applied to other ventures than dredging in that line, is, perhaps, not saying a great deal.

Having committed myself to this statement the necessity of going a step further or of retracing is a natural consequence. However, I am not going to retrace, even at the risk of posing in the character of a Dcusterswivel. All such places where the valley of the Molyneux opens out into

Wide Open Basins such as at Cromwell, and the basin between Clyde and Alexandra, and again the wide expanse at Moa, Anderson's, and Miller's Flats, and the Avhole of the Manuherikia Valley are very favourable to the lodgement of gold in moderate quantities, which, if they do not come up to the sensations of the ' Kawarau, make up by permanent and- regular yield for what they lack in surprises, both pleasant and otherwise. Claims- situated in the basins mentioned may be regarded as safe investments, returning very handsome interest but no sudden fortunes, provided of course that the conditions of working them are favourable — no double or treble banking — and the machines employed are of a capacity and efficiency corresponding to the requirements of the ground to be worked.

All such places where the rivers and the valleys of the Molyneux and Kawarau contract into

Naiiuow Rock-bound Gorges may safely be marked as the site of rich and even surprisingly rich patches and disappointing blanks. These are the homes for gambling and speculation. Shares jumping up one day to a fictitious premium to fall next day as far below it. The Kawarau illustrates this phase of mining speculation, also the gorge from Cromwell to Clyde, and in a less degree the gorge between Alexandra and Roxburgh. Anyone wishing to go in for speculation and mine gambling, or wishing to make a quick rise and great returns for his money in a short time will find these places suited to Iks purpose, but he must take the risks that are inseparable from gambling of every kind.

These observations are founded and borne out by long experience. Every river, stream, or valley in northern and Central Otago confirms it. It does not apply to the Molynenx or Kawarau alone. There are good, sound reasons — scientific, geological, and others — for It. The investor is confidently recommended to act upon it.

IX.— THE MOLYNEUX RIVER. The Entkrpbise Gold Bredgikg Company.

This claim is a bank and river claim,

and has been worked for : four and a-half years with almost unvarying success: The claim is situated about two miles above Alexandra. This company is also a private one, the dredgemaster being Mr S. G. Luke, who came down from the Wakatipu to manage the dredge, and who has been in charge ever since. The dredge ranks .with, the old ones, and is totally out of date. At several stages of her existence she has been renovated in part, to keep her abreast with dredging progress, but- in spite of all this she has now dropped hopelessly behind the times, and I hear steps would have been taken long before now to her by a new and up-to-date boat "were there any chance of getting the work done with anything like reasonable expedition. However, in spite of being, far from a crack boat, she has done very well, as will be seen when it is stated that by last balance sheet she had paid 16s in dividends for the year covered by the balance sheet, and there have been years when she- has done much better. It is stated that altogether "the dredge has obtained upwards of 5000oz since the time of starting work, which is a veiy good record for a dredge of her calibre. For ' the year "to which the balance sheet refers she averaged 250z- per week, and there were 45 working weeks, the remainder of the year being consumed in repairs, etc. This is a very good average, and speaks volumes for the dredgemuster, proving him a careful and experienced manager, who understands his- ousine&s.

Mr Luke is an experienced miner of manyyears' standing, and as he has worked for a long time upon the banks of the Kawarau, he has a good idea of the conditions now under consideration. The Enterprise claim on the Molyneux has been worked for about half a mile wide, the whole of which was payable ; and, so far as the banks of the river have been worked, there is no abatement in the richness of the ground, Mr Luke finds that the gold runs in streaks, divided from one another by ridges of varying heights, which are "comparatively poor, the best gold being found in the troughs, where the wash is more stony and tighter than on the dividing ridges. The bottom is a soft clay and broken, rotten reef, easily cleaned up. This is the case generally upon the river, and it is accepted that the rotten reef will, at no great depth from the main bottom, harden in descent; until it corresponds with the rock outcrops at the surface upon the sides of the valley.

About 20 acres of the claim htive been turned over, the claim containing about 100 acres, some of which is high bank, measuring one mile along the course of the river. At the. present rate of progress it will take 15 years or more to work out' the claim, \and, as Mr Luke remarked, .then it can " be ,gone over again with a mew dredge,- and be made ' to .pay once more. The groumtas rough and stony, and, though difficult to»work, it is made to pay without any undue strain upon the machinery. The depth dredged averages from 30ffc to 3,5 ft, being deeper in the stream than in the banks ; hence the system which is generally followed by dredgemastcrs upon the Molyneux — i.e., working in the current of the river in the winter, when the water level is at a minimum, and attacking the banks in the summer.

The Enterprise is known as the dredge ""upon which Messrs Cutten Bros, made their experiments with the first elevators ever worked in connection with any dredge, and which has proved so eminent a success that without it dredging would not be what it is now. Although only four and a-half years afc work, a look at the machinery shows the progress that has been made in dredging affairs in that time. The company was registered in 1891, with a- capital of £3000, £2000 of which was called up. The gold produced for the period covered by last balance sheet was llOloz. The company has paid £3121 in dividends, and in. addition spent about £4000 on the present boat. The elevator has done good work, as is proved by the heaps of tailings which now flank the river bank.

The Ngapara Gold Dredging Company^.

This company, whose claim' joins the Enterprise at its lower boundary, is a private one, the shareholders comprising some of the most successful dredging men upon the river. The dredge was built in 1895. and has now been at work for three and a-half years.

Mr R. Ross, who is dredgemaster, and a shareholder in the company, pointed 'oufe how necessary it was to make improvements in the old dredges as >new innovations came out. Although the dredge is only three and a-half years old, quite an appreciable sum has been spent to keep the dredge up to date. This fact illustrates the rapid strides that are made in advancing the industry. The latest innovation in the Ngapara dredge was the elevator, which had become necessary in order to stack the tailings, in order to gain room for working the dredge. Until the elevator was put on there was some difficulty in working the high banks abutting on the claim. This has now been overcome, and the deepest, or rather highest, ground within the pegs of the Ngapara claim can now be worked with ease. As stated, the company is a private one, there being only six shareholders. The party, by a tacit understanding amongst themselves, keep their accounts from publication.

The dredge is a well-appointed one in every part, and is strongly built. The pontoons are of steel, and Mr Ross, the dredgemaster, speaks highly of them, inclining to the opinion that* steel pontoons are worth the advance in cost, which amounts to £300, over wooden pontoons. When it comes to taking the dredge to pieces, in order to shift to another place, the extra cost of steel pontoons would 'be almost saved. Steel pontoons give a; rigidity to the deck that no wooden ones can do, thus interfering as little as possible with the true and even working of the machinery, a desideratum that cannot be over-estimated in a dredge, hard and rough usage being inseparable from the work it has to <&v Another distinction in tbi*

dredge is that the connecting links are channelled, being made broader at their outer edges, that travel over the roller of the ladder and the tumblers. In this manner yvaa.r and tear is reduced in the links, *as tf'eil as in the rollers and tumblers, reducing- at the same time' the weight of the. linlis: \Tlie halyards, or gallows, for raising' 'issi jla^e/inff the ladder are also of steel. TJie steam winch is of extra strong . friild'," consisting of six double barrels and one single one. The friction wheel is of ingenious construction, and answers well .the purpose it is designed to serve. The boiler is partially sunk in one of the pontoons, which answers admirably, giving the boiler — which is an external fire one — the greatest possible heating surface. The gold-saving apparatus consists of a revolving screen 4ft in diameter, and tables fitted with expanded metal, cocoanut matting, and other appliances for arresting the gold. There is a 10-inch Tangye pump for supplying the cylinders and tables .with water. The dredgemaster is satisfied that his gold-saving appliances, though they may not save all the gold,- are as efficient for that purpose as any on the river. The elevator is formed of trays in place of the ordinary bucket, the trays having the advantage of shooting the tailings farther away than is done by the perpendicular drop from the bucket. The buckets, of four cubic feet capacity, are exceptionally strong. The engines are 14 h.p., and the boiler 16 h.p. The belt is furnished with grabs of the usual construction, and do good work amongst the big stones, of which there are a good many. , The engines, as well as the pontoons and nearly all the other machinery and gear on board, were furnished by the New Zealand Engineering and Electrical Company (Limited), and the owners express themselves highly pleased with the turn-out. Taken altogether, with her steel pontoons, compact and strong appointments in all her other divisions, the Kgapara dredge may be pronounced as, for her size and capacity, one of the strongest, if not the strongest, dredge afloat upon the Molyneux. . The dredge has been working three and a-half years, during the whole of which time Mr Ross has been in charge. In the time stated 15 acres of ground have been turned over, and as the claim of the company comprises 94 acres, a great part of which is bank, and fairly tall at that, the claim is estimated to last for 15 years to come— an estimate, • I should think, quite ■withrn the mark. Mr Ross, who is a duly qualified engineer, has had 16 years' experience in dredging, and his opinions on the subject, therefore, are entitled to respect. Broaching the subject of the course of the run of gold, he opined that the statement of the runs striking across the Molyneux had not been sufficiently proved. His own experience favoured the string of patches theory, and he instanced a case where he got 70oz out of a very small piece of ground, all round- which the ground was scarcely payable. Similar experiences were repeated in other parts of the claim, and there seemed to be no particular connection between the patches. On the score of the gold going into the banks on either side of the river, Mr Ross had not the slightest hesitation in expressing a decided opinion in the affirmative. 'At and in the neighbourhood of the claim the river and its banks have been worked to a width of from 600 yds to half a mile, measured at right angles, across the stream, all of which was payable. Like most dredgeinasters of lengthy experience, he was quite satisfied that the gold got even better going into the banks.

Mr Ross kindly showed me a sample of the gold, panned out from the mat, which, examined under a good microscope, had a solid, grainy appearance and good colour. Some of the pieces are entitled to be called coarse, and perhaps the bulk in weight is of that description, the really fine or dust gold making up the lesser quantitj r .

The subject of the gold and its extension into the banks is a matter of the greatest importance, in a practical as well as economic sense, and any information on this •point scattered here and there through these articles should be assimilated by investors. Pei'haps when the descriptive parts of these articles are completed something more will be said on the subject. The Golden Point Gold Dredging Company.

The dredge owned by this company is one of the latest additions to the boats afloat upon the Molyneux. Though not one of the most capacious, she is strongly built and has powerful engines. The engines are by Garrett, and are of 20 nominal h.p., working up to 112 indicated n.p. This dredge was designed by Mr Edward Roberts, and was built by Mr Thomas Luckie, of .Queenstown. The buckets, ladder, and elevator were supplied by the Dunedin boundary Company and Engineering Company. The winch is by Roberts, of Bendigo, Victoria.

There are two boilers, supplying a sufficiency of steam for all purposes and to spare.' The bucket ladder is 65ft long, and is capable of reaching to a depth of 40ft to 45ft deep, working at that depth with the same ease as at any higher point. The ladder is of special build and strength, a great degree of rigidity being attained.

Where the Golden Point dredge has the greatest advantage over other dredges is in the elevator, which is 70ft long, and is calculated to stack the tailings from 40ft to 45ft high above water level, so that there is a difference of from 80ft to 90ft between the level from which the golden gravel is lifted to that where it is deposited as tailings. This is moving in the riiht direction, and this difference doubled would probably mean the solution of the difficulty met with in working any — even the highest —banks upon the Molyneux. There is no reason for supposing that either power or strength' of material makes such an increase impossible ; so that after all we are nearer the solution of the difficulty than is generally supposed. The winch workiner the boat is by Roberts, of Bendigo, Victoria, and is a euueripr piece of mechanism, giving; great

satisfaction. The buckets are of 4£ cubic feet capacity, and of corresponding strength. Another item showing the strength of construction is that the pins connecting the links in the belt are 2in in aiamater — a thickness, I believe, not exceeded on any other boat on the river. There are two screens and two tables, giving about 400 ft surface area, treating from 60 to 70 tons per hour. All this work is achieved by 18 to 19 bags of lignite being burned every shift of eight hours. The dredge has only been at work for 14 weeks, and averaged from 260z to 270z per week, all stonnages inseparable from starting new machinery included. What made the start more difficult was the fact that deep and very' stony ground Tvas met with, which inevitably adds to the difficulties of starting new machinery.

The depth of the bank above water level averages aboufc 25ft to 30ft, and is amongst the highest attacked. There is payable gold all through, the gravel, so that it will be seen there is the incentive to devise some means of putting the whole of it, rising to 60ft or 80ft, through the screens and over the tables, the yield depending wholly 9ml solely upon the quantity treated. The dredge and machinery were built and furnished by the New Zealand Engineering Company, Dunedin, and the dredgemaster, Mr D. Bringans, speaks in high terms of the excellence of the work and the precision with which everything -on board works. The gold-saving apparatus is of the' usual description, only that there are two revolving cylinders, or screens. Expanded metal is used upon cocoanut matting, and Mr Bringans speaks highly of the satisfaction this arrangement gives. As he saves some very fine gold, he is qualified to speak with -no small degree of authority on the subject. Mr Bringans has been in the dredging line going on for 10 years, and scored a considerable degree of success in that profession. He feels quite confident on the subject of the runs going into the banks of the river, and takes a comprehensive view of the importance of the fact. In his opinion, the available evidence at the present time is quite enough to settle the question. Mr Bringans has evidently thought out the subject in all its bearings, and is of the opinion that an elevator ladder 150 ft to 200 ft long would work all the ground upon either bank of the Molyneux between Clyde and Alexandra. He also holds that there is nothing not feasible in such a project, and, so far as things have gone, his opinion is fully borne out. We have now dredges with elevators 70ft ,t, t long giving every satisfaction, and lands us'halfwav to the required mark. The dredge is lit with acetelyne gas, which is highly spoken of by the drcdgcmaster, being far to be preferred bofore kerosene.*