MINING.

Otago Witness, Issue 2265, 29 July 1897, Page 18

MINING.

THE EISE AM) DEVELOPMENT OF l>R£l*tiifftt IN OTAGO.

(By Ouk Roxburgh Cokkispondent.) ' VII. Tbe Ngapara dredge is owned by William Milne and party, and works about one mile above Alexandra- on a beach claim, which is' 44 acres in area. Neighbouring dredges are the Earnscleegh No.' 1, Enterprise, and Chicago. At present work is being carried on a considerable distance frcm the river, but tbe party intended, at the time of my visit, to work their way out into the river for tha winter. The river .here takes the shape of a huge basin, and mutt be nearly' three-quarters of a mile from bank to" bank. Being a private s'company, the returns are not published/ but they have been frequsntly reported to rea«is 90oz a week. Sixty and seventy ounces a week have also been mentioned. The dredge was 'built by the New Zealand Eogireering and Electrical Company, who have been for tome time past; very bu»y with dredging contracts on the Ciutha, Nevis, &c, and work was commenced in September 1835. The men working the dredge are mainly shareholders and old dredge hand*. Tha pontoons are of steel,- and the principal dimensions are:— Length, 75ft; beam overall, 32ft 6in ; depth. 4 t 6in ; width of well, 4ft 6in. The ladder is 54ft long, and on the bucket belt there are 30 buckets, each three cubic feet in capacity, and discharging at the rate of 13 a minute. The poppet head is much higher than the average, and enables the revolving screen to be placed sufficiently high to ■ dispense with * tailings, elevator. The chute _pUces the tailings leveral feet above water level. A centrifugal pump supplies the weter for the tables, which discharge into another semi-circular-chute. The dredge is supplied with ma up-to-date steam friction winch with seven barrels. Tbe winch is driven direct; fiom the boiler, wh : ch works at a pressure of 1001b. The engine it vertical, surface condensing, 12- horse power nominal, and tha motive power • is transmitted from it to the top tumbler shaft 1 opes on pulley wheels, the large one being 7ft in di*meber. The dredge underwent repairs in the beginning of May, and h*s since been working well with good returns. CLYDE DHEDGIXG COMPANY. In dealing with this company I will .give, first, a description of the dredge withexpentes ; then particulars of the gold won, together with ft history of the company since inception. The- dimensions of this dredge, known as the *• Moa," are as follow : — Length', over 90ft ; width of beam, 27ft 6in; depth, aft 6 :t, forward .sft ; width of ladder way, sft 6in. * The hull U very substantially built; of timber, and the frames are of hardwcod, plunked with kauri, red pine being also used in some parts. The gantry is very, strong, and consists of posts 10In by 12in, fixed at an angle of 70deg witk the deck, and braced by tie rods fixed to the bow. To prevtnt "hogging," four hog pos's, 28ft higb, snd of lOin by 12in timber, are placed vertically in the pontoons 30ft from tbe stern ; and there are four timilar posts tte is me dittsDCo from the bow. They are braced diagonally, and stayed from the top with iron rods, If in in diameter, with union screws. They serve another purpose in carrying the tailings elevator,' which may be raised or lowered by a winch at any time while the dredge is working,* The elevator is also supported from the stern by two timber stays Bin by Btn. The boiler is a Cornish multitubular one with tapered shell, and works on an average at . 1201b to the square inch. It is 14ft long, witb » 2ft smoke box, and is sft in diameter. The funnel is 35ft high. The maker of the boiler was Mr R. &: 'Sparrow, who also supplied the winch, tcreeo, ladder, and other machinery. ' Th©' engine is horizontal,' compound, surface .condensing, 12-horse power nominal, or 50>-horse power indicated, and was made by Marshall »od Sons; --Qainsborough. The motive power it transmitted" by-Dick's patent belting through four spur wheels to tbejiop tumbler shaft. •The winch is six-barrelTfcsJ^ead line, ladder, and four, side lines), with brakeffnsa.the barrels. Tbe winch i» driven by ir vertical '"Marshall engine, ' with , two sin cylinders. The firfct motion is by bevelled' wheels, and the laifc motion is by worm gear with friction clu'ehes. There is also a hand winch for an additional tide line. The ladder is b7ft long, acd is at present down about 33ft or 34ft. There are 34 buckets, each containing three cubic feet, aud they are capable, iE running full, of lifting 80 cubic yards, or 120 tons of material, per hour. To prevent the sides of the pontoons being knocked about, two heavy chafing beams are placed one

each side of the well. The tumblers are "clad." The washdirt is discharged by the buckets into a 16ft revolving screen, of which 12ffc consist of performed plate* with fin holes. The screen is driven by beyelled wheels on a shaft at right angles to the second motion shaft. A perforated pipe allows a certain amount of water to play on the dirfe as it; passes through the screen. The fine material passes over the gold-savijig tables, which are on e*ch sid« of the eereeb, and placed athwartship, ■ The tables are each 10ft by 10ft, fitted with'cocosnut matting and expanded metal ; the return tables underneath have latitudinal ripples. Not much gold i* caught in the latter iables. There is »lso a "catch-all." Sluicing water is supplied by a 12in Tangye centrifugal pump. The tables are washed up twice a week, "Wednesday and Saturday, the top m&ts being taken up oftener. The tailings elevator is driven by belting off the counter shaft; and power spur whs eh, from the bottom tumbler. When working -\t full length there are 76 trays, but there are at present only 52. The elevator itaoks' to a height of 30ft to 35ft above the watar, bat it is nob used at present, as the current is sufficiently Strong to carry away the tailings, which are discharged into the river from the screen by a 16ffc chute. The poppet' heads, on which rest the top tumbler gearing &c, ara 9ft from the deck. The reason why th«-y are so low is that nob bo much power is required to pump the water. , Higher poppet heads are more in use. The working expenses per week are about £37, of which coal, at 14s per ton, amounts to I from £13 to £14. Seven men are employed by the company. The dredge cost somawhe-e ! about £4000. The co-t of production per oucce of gold was £2 16j 10£ din 189 S. The Moa was fitted up by Mr John Scot 1 ", who also fitted up the Ophir and lod dredge at Blacks, and lately he has been fitting up the Gofden Crown dredge at Waikais. Mr E. Roberts, a notable civil engineer of Dunediu, was, I believe, the designer of this dredge, and he asa prepared tbe whole of the detail drawings and specifications of the Molyncux hydraulic dredare. The Clyde Dredging Company was registered on May 17, 1895, with a capital of £4000, divided info 80 shares at £50 each, three being" , i.'su.°d fully paid up to the vendor. On April 3 the shares were quoted at £65 to £70 ; on June 11 they were at £45 .to £50 ; bat on July 17 they had riaen more than 100 per cent., tbe market price being £95 to £100, ex a dividend of £10. The dredge wss built on the company* claim ; at Mutton Town Golly, comprising 60 aerts, : but it has not yet worked the claim it was j built for. The Moa commenced to work immediately on the boundary of *;be Golden Beach hydraulic claim, and from November 16, 1896, to February 1897 won as much as £3800 worth of go.d. On January 6 the dredge, which had bean worked for 11 weeks by Mr Roberts, engineer, under a tribute arrangement, was taken over by the company, the agreement having expired. DoriDg the time the dredge was nnder Mr R'.berts'B management he oompleboly disproved S aU the statements- that wera current last year ! respecting the dredge's capacity for work. A large quantity of ground was turned over, | yielding over £1200 worth of Rold, and the depth dredged was between 25ffc and 30ft", while the stack of tailing* above water was 20ft high, and measared about 10 chains round. One statement made that 25 minutes were required to lift the ladder from the bottom was completely disproved, as it was lifted easily from a depth of over 20ft below water line into a position ready for chocking above the deck in smin 15«fc. On taking possession of the dredge it took Mr Roberta's men a few days to repair the damage done to the engine, which had apparently been taken to pieces by his predecessors and wrongly put together, thereby resulting in serious damage to the valve and valve jpiodles. Since then, however, go further trouble has been experienced. One shareholder* told me he thought Mr Roberts had saved the company £1000 by taking over the dredge, which was on the pjint of liquidation, being £1400 in dett. [L state the above on the authority of one of tbe shareholders,} Me Bringan* w»s dredgemaster under Mr Roberts, but he resigned shortly, after the expiration of the tribute agreement, and since I then Mr W. S. M'Callum has been in charge. i The latter was for some time engineer on j Crookston and party's 'dredge. Lowburn, and was also once engineer on the Roxburgh dredge. In May, when the dredge was repaired, the I shareholders at a general meeting decided to take the Moa down to the lower end of tbe ! celebrated Frenchman's Point, \»hpre it was known & portion of that famous lead was unworked. Mr M. Kit in nine years and a-ha'f took between £70,000 and £80^000 worth of gold out of his claim at this point. Several attempts have*een made sicce Kitt left to pick up the lead, but through varied circumstances were unsuccessful. The claim is known as the Grand Junction claim, and includes tho mouth I of the Mauuhecikia River and Batcher's Point. I think this claim is the one assigned to the company by Dr J. G. Hfde. The Clyde Dredging Company have at present under application a claim, 75 acres in area, expending from tha mouth of the Maouherikia River to the mou'h of Stockyard Gully, taking in all* the Pro.-pector's Point on tha east side noar tbe mouth of tbe Manuherikitv River and that portion of the Molyneux River extending from below the bridge down to the lower end of Frenchman's, and taking in all Frenchman's f Point. The Moa commenced operations on the Grand Junction claim on Taesday, Jane' 8, and on the following Saturday washed up for ♦6-'z7dwt. The next week's work resulted in a return of 1570z 9dwt Bgr, of wh'ch 89oz , lldwt 2gr were Won in three days. For the lieii; three weeks the returns were 107oz ldwt 6gr, llSez 4dwt 12gr, and 88cz respectively ; and on tbe VTth insfc. the wash-up was 78oz. For the 34 working days feoin June 8 to July 17 the total gold yield was 5900z 2dwt 2gr. of I the value of £2271 17s 4d, equivalent to £66 I 16s 4£d per day. I On March 24 the first dividend of £5 per share was declared, and £250 was placed to reserve fund. On June 24 another dividend of £7 10s was declared, and the reierve fund was

increased to £500. On July 12 the third dividend of £10 was declared, making in the short spac! of fnur months a total reimbursement of £18C0, or 45 pee cent, on the capital Needless to say. tbe excellent returns of the Moa dredge have caused quite a stir in dredging circles in Dunedin. Reverting to the success of the Moa on the Grand Junction claim, I tnke the following from the Dunsfcan Times of Jane 18: — "The chief topic during the week has been the splendid and immediate 6uceef-$ of the Moa vtorkiiix at the lower opening of Frenchman's lead. The returns were 45£oz for about five shifts af ber gold was first itcuck, and 89ioz for the three following days. The reason for so much interest heing taken in this dredge's operations is that so many of our old miners have worked in Frenchman*, and have seen the marvellous returns of this perhaps unequalled le«d. Ifc has always been an open and vexed qaeetiou whether the lead continued into the river or not, but the Mca hw settled all doubts on the subject. The value of this property has been estimated at from £4000 to £40,000, according to the temperament; of the Valuator. The find is infcerebting. because it proves that, given dredges of sufficient power wnd capacity, suitable portions of the river in the gorges may now be worked, the drift overcome, and our river made to yield up its treasure?. Bat large dredges will-ba required, even larger than the Mo&. Another poiDt of interest ia that, although a. rock and boulder bounded claim, no large stones have yet been lifted by the Mo», proving thab though the sides of a river may ba rougb, it is' no reason to conclude that the bottom or bed of a river will necessarily be unworkable. Of coarse there is a limit to the possible working of tab gorges by dredges, yet we confidently expect to see at; no distant date many suitable cites in the gorges dredged with satisfacbory rcults. Ib is hard to realise that/ such a property h is remained so long at our doors undeveloped ; but ib mutt be remembered thnt modern dredges ha.ye, with rheir big buckets and b ; gh elevators, bub recently euiiblod miners to cope successfully with difficulties which prestnb themselves in working this claim, and we must not raenly condemn our minirg predecessors for lack of enterprise or want ot ' savvy.' '•' THE VICTORIA DREDGE is a comparatively recent veisel. and was firsb thß properby of -a private *party, but ib has been purchased lately by, I ucd9rstand, a public company. The dredge was origin a 1 ly built as a currentwheeler to work a claim in the gorge near the Fourtean-mile Beach, bub she never went down there. The pontoons are 84fb long, and each 7ft 3in wide ; ladder way, sft 3in ; length of ladder, 49ffe. At present tbe dredge is bsing converted into a steam one. The company have bjughb si first-class Marshall 12-horse power boiler and engine, and Mr Cutten is fitting up tha dredgu ac Sandy Point, where ib • sank some time ago. The dredge, when completed, . will be taken up to what is known as the Central Otago cla<m, near Clyde and it is thought that she will soon pay for heraelf on fchi- claim, a3 the company is small and the dredge 'as-bought cheaply. Tbe old .rreufc waeels were 22ft in diameter, and had each 14 floats. Afsaming the current to travel from flve to fix miles per hour, it was estimated that thefe wheels developed 15-horse power. The wheels revolved seven times a minute. Ths buckets each hold two cubic feet, and were estimated to raise about 48 cub:c yards per hour. The method of washing the dirt is by screen and babies. THE EUREKA NO II is another large steam dredge, and commenced work abauS 12 months ago. The owners are Messrs Leijou, Magnus, and Steel, who also own the Euceka No 1, and the claim is situated a little higher up the river than the Golden B'fach claim. The motive power is generated in one of Pajne's boilers, which works at a pressure of 1251b to the square inch. The engine is a Marshall 14-horse power nominal, and the wiuch i» a barrel winch with friction gear, driven eff the first motion shaft. A long screen is used to wash the dirt, and the tailings are stacked by •n elevator with 75 trayi "driven from the boifcom tumbler. There are 35 backets, each holding tbree cubic feet, and two grab-hooks with shoes. The dredge is capable of i>isirg 84 tons per hour. The timber pontoons are 94- .'fc long, 24 ft ia beam, and sft in depth, and the well is 4ft 6in wide. Hog-pofts have been erected to prevent " hogging," and also to carry the gays for the elevator. In eight mouths th : s dredge won £3449 worth of gold, and is reported to be doing very well at the present time.