George Green, 1810-1872 "Pioneer - Shipwright - Landowner - Inventor"

George Green was an early buyer of land in New Zealand's South Island.  He bought lots of land.  Unfortunately for George, nearly all of his land dealings occured before the Treaty of Waitangi in 1840 and he spent many years attempting to have his purchases recognised by the New Zealand government.  George Green's biography can be found here and, since someone has already done the work for his overall story, I will concentrate on his invention.

By the end of the 1860s, Otago's gold rush was in full swing.  The gravel beaches of the rivers, mainly the Molyneux or Clutha, had been worked as much as the fluctuating water levels allowed and it was well known that the gravel and the gold extended under the fast flowing water.  

First attempts to safely dig the submerged river beds involved a spoon dredge.  This was a hoop on a pole, the hoop holding a leather bag which held the gravel scooped by the spoon.  This was usually mounted between a pair of pontoons to float it over the river.  Te Ara has an excellent depiction of the arrangement here.

Spoon dredges worked and showed that the gold was certainly there.  But they were cumbersome, dangerous and not reliably profitable.  Some outfits tried divers in suits on the river beds, guiding the spoons to the more likely places.  But, even weighted as heavily as possible, the divers were unable to cope with the strong river currents.  If only miners could dig the rich gold from the very bottoms of the rivers.



NEW DREDGE FOR THE MOLYNEUX. 

THE PATENTEE is prepared to enter into liberal arrangements with persons desirous to supply themselves with his new Patent Dredge for raising washdirt from the beds of auriferous rivers, or conveying water on or to the banks or slopes thereof for sluicing purposes. 

Full particulars can be obtained of his Agent, Mr. George Murray, Shamrock Hotel. Dunedin. 

GEORGE GREEN, Patentee.  -Otago Daily Times, 14/7/1871.

From an advertisement in the “Daily Times” it appears that a Mr. Green, the patentee of a “new dredge for the Molyneux” is prepared to enter into liberal arrangements with persons desirous to apply themselves with his new Patent Dredge for raising wash-dirt from the beds of auriferous rivers, or conveying water on or to the banks or slopes thereof for sluicing purposes. We wish him every success in the undertaking. The following are the particulars of the invention as taken from the same journal: —The vessel is sixty feet long, and is to have a flat bottom, square steam, and long sharp bow, so constructed as to offer the least resistence to strong currents. She can be deeply immersed when that is required, by the admission of water through valves in her sides, thus bringing her nearer to the ground to be worked upon. She is fitted with a divingbell of sufficient size to enable two men to be constantly at work therein, procuring and sending up wash-dirt. This bell is of a rhomboid shape, being sharp at the ends with convex top, and may be used with or without shifting weights, to be attatched as the bell descends, to counteract the buoyancy given by the supply of air to the workmen, and to be detatched as it emerges from the water. The dredge will also have a pair of paddle-wheels for the purpose of working a pump or pumps to convey water on or to the banks of rivers, for sluicing or any other purpose, and by a simple contrivance the paddles can also be used to warp the vessel from place to place when desired. We look upon this invention as likely to effect a complete revolution in river dredging, as the spoon dredges are notoriously inefficient, and all the present appliaucs for getting gold from the depths of rivers are, in the opinion of most practical workingmen, comparative failures, inasmuch as they cannot reach the richest deposits in clefts, seams, pools, and in the numerous bars in the stream. By Mr Green’s process, however, the men can go down onto the reef in any part of the river, and literally sweep the same with a broom, thus lifting everything to the most minute scale of gold. We learn from Mr Green that he has already entered into negotiations for placing at least two of his vessels on the Molyneux, and we wish them every success. Lithographic drawings are now lying at our office for inspection, as also at Mr. Hazlett’s store.   -Dunstan Times, 21/7/1871.

By reference to our correspondence column it will be seen that Mr Green, the proprietor and patentee of the new Dredge and Diving Bell, has, in response to a suggestion we made in a recent issue, now given fuller particulars as to the proposed method of working. This very careful and lucid description will enable the reader to form a better opinion as to the value of his invention than could be possibly gained before. It is almost a matter of regret that Mr Green has not already one of his machines in working order on the river. “Seeing is believing.” He has only to prove by actual experiment the value of his invention, and his just reward as an enterprising inventor will be most amply assured.  -Dunstan Times, 18/8/1871.

ORIGINAL CORRESPONDENCE

[We do not identify ourselves with the opinions that may be expressed by our correspondents.] 

PATENT DIVING BELL DREDGE

 (TO the editor of THE DUNSTAN Times.) Sir, —In a recent issue of your paper I observe some notes on my patent diving bell vessel, the writer of which suggested a few points for explanation. With your permission I now beg to supply the same. We will suppose the vessel moored over the spot at which operations are about to commence, and that the beach contains about six feet or more of surface tailings over say two feet of wash dirt. The first thing then to be done is to drop the bell within one foot of the surface of the beach. In the bell are two men, who forthwith commence to shovel astern one foot in depth of the material under the bell, after which the tailings require to be lifted to the surface in buckets or bags, and passed away astern, till the wash dirt is reached, which of course is sent up to the deck and dealt with for gold in the usual way. After all the wash dirt is collected the reef is then carefully examined and cleaned up, and here I expect the largest quantity of gold will be got. The area of the bottom of the bell is seven by six feet, and there will be no difficulty in working nine by seven feet to the bottom. Supposing this process to be thus completed there is an opening or paddock left of nine by seven feet. Now I propose to advance seven feet up the river, and repeat the same process, which will give me a paddock of eighteen feet long by seven feet wide. Therepon, instead of the tailings being raised as describe above, the men in the diving bell shovel everything into the paddocks astern until the wash dirt is reached. You will thus perceive that after an opening is once obtained, the minimum amount of labor only is required to deal with the tailings, as the same no longer require raising, but are shoveled into the paddocks astern. It will doubtless be said that the paddocks are likely to be filled up by the tailings always passing down the river; but I contend this will not ordinarily be the case, although it may be liable to such eventuality in times of flood, so are all the river beaches, but such difficulty is more readily overcome by my mode of working as it is only required to repeat the first operation and the work progresses as before. Another point not generally understood, is the bell passing through the tailings to the depth stated, say six feet or more. It has been suggested they would fall in on the bed, this could not occur by making the paddock double the size of the bell as already proposed. The fact is, the deeper the bell goes down the greater the protection afforded to it by the upper bank; for the bell is but five feet high, as soon as that depth is reached the current is absolutely passing over its surface. I say that my bell can work such claims with the utmost facility and clean up the reef at the bottom, which is more than any known method of working can accomplish, and I believe that any practical dredger can at once realize its importance in this direction. I would merely add that there is nothing novel in a diving bell excepting in its application to its present intended use. I have had upwards of forty years practical experience in diving bells, have personally worked in them and have to stake my reputation on their successful working, provided the gold is in the river, of which there appears to be no doubt, when I see your paper reporting dividends to some of the present dredgers of 40l to 50l. per man per week with the present inefficient mode of obtaining it. Yours, &c, GEORGE GREEN, Patentee.  -Dunstan Times, 18/8/1871.


Alas, for all Mr Green's ingenuity, he could not find a backer, for all that the gold was waiting there to be dug up somehow.  In this writer's opinion, the success or otherwise of Green's diving bell would depend on the strength of the river current over the river bottom where the gold-bearing gravel would be found.  I personally doubt that it would have worked.

There are only ten dredges at work, and the owners are extremely reticent as to their earnings — probably making just average wages, and nothing more. It is suggested that the river claims may yet be made to yield remunerative returns, if a good system of co-operative association is initiated, and some more effective machinery introduced than the spoon dredge; but there is an evident lack of local speculative enterprise. Many diverse schemes are propounded, but the great want is some bold and inventive genius to strike out a newav line of action. Mr Green's theory of the diving bell was not believed in, simply because miners are essentially believers only in what they see, and can actually test by practice. Any clever inventor who will experiment rather than theorise will meet with good support. As an evidence that at present dredging property is at a discount, fifth share in the Kearsage, lately belonging to a miner who was drowned in the river, was knocked down at public auction for £10, bought of course at less than its actual value, from the fact that just now few individuals care to invest in property yielding such uncertain returns.  -Otago Witness, 30/9/1871.

The diving bell principle was further developed and actually built as the submarine gold dredge "Platypus" - built and tried in Dunedin and now residing (or, at least, much of it) beside the museum at Middlemarch.  The story of the "Platypus" can be found here.

The profitable exploitation of the riverbeds - and, eventually, the ancient riverbeds near the large rivers - was finally realised with the invention of the steam-powered bucket chain gold dredge, built for Charles Sew Hoy in the late 1880s.

Southern Cemetery, Dunedin.