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Clutha River Suction Dredge a Failure

simon		Posted : Saturday, 20 October 2012 11:21:42 AM(UTC)
Rank: Gold Ingot Groups: Registered Joined: 7/01/2011(UTC) Posts: 789 Location: Central Otago Thanks: 33 times Was thanked: 239 time(s) in 150 post(s)		unfortunately i don't think that suction dredge ever had any luck on the clutha. when i first saw it i thought of the similar one at maori point. it could reach the bottom and i think they found the bottom very clogged with immovable boulders in hard pack. now the joke is they need consent to remove it from the river to run any mods or to remove fully. http://www.odt.co.nz/reg...redging-operation-ceases
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ccam26		Posted : Tuesday, 23 October 2012 10:56:31 PM(UTC)
Rank: Gold Flake Groups: Registered Joined: 3/05/2010(UTC) Posts: 16 Location: dunedin Was thanked: 2 time(s) in 2 post(s)		anyone know what sort of recovery system they had on it? im guessing it could be that that has let them down or hydrolic issues again. the suction nozzle from what ive heard is on an arm and has a huge range of movement and a camera attached so they can see what is going on also a large grab/claw arrangement for shifting large rocks

icemaneli		Posted : Wednesday, 24 October 2012 10:29:26 AM(UTC)
Rank: Gold Flake Groups: Registered Joined: 5/09/2012(UTC) Posts: 19 Location: Darfield Thanks: 1 times Was thanked: 1 time(s) in 1 post(s)		Sounds like what happened to the grey river dredge, originally set up as a suction cutter but didn't handle the large boulders in the gravel too well and the whole company ended up being sold for way less than start up cost. It then was converted to a bucket ladder dredge and continues to work today (i think). Maybe they will try something similar in this case.

kiwijw		Posted : Wednesday, 24 October 2012 7:12:40 PM(UTC)
Rank: Gold Ingot Groups: Registered Joined: 28/03/2010(UTC) Posts: 1,152 Thanks: 92 times Was thanked: 658 time(s) in 324 post(s)		I think you will find that the Grey River dredge is no more. JW

garrymac		Posted : Wednesday, 24 October 2012 9:35:53 PM(UTC)
Rank: Gold Nugget Groups: Registered Joined: 3/03/2011(UTC) Posts: 84 Location: dunedin Thanks: 26 times Was thanked: 26 time(s) in 19 post(s)		Originally Posted by: kiwijw I think you will find that the Grey River dredge is no more. JW The truth may never be issued in public, but the dredge has been plagued with problems since the day it tried to get in the water-- electonics-- hydraulic---systems--and tailing build up.. More money needed bigger suction pump. A lot more could be said but not here

fastangler		Posted : Wednesday, 24 October 2012 9:45:29 PM(UTC)
Rank: Gold Nugget Groups: Registered Joined: 1/10/2010(UTC) Posts: 37 Location: christchurch Thanks: 17 times Was thanked: 14 time(s) in 9 post(s)		the grey dredge is still working away near blackball,went past it every week while i was up moonlight. i heard it relocated to ngahere a few years back,i dont no the whole story but i do know that its still on the grey

Lammerlaw		Posted : Wednesday, 24 October 2012 10:13:50 PM(UTC)
Rank: Gold Ingot Groups: Registered Joined: 24/05/2011(UTC) Posts: 1,721 Thanks: 72 times Was thanked: 579 time(s) in 396 post(s)		A great pity that it has not panned out for the guys as it is great to see people being rewarded for giving it a go - as for the consent to remove it or modify it - that is a farce and an indication of the police state we have become. Those guys should have the right to remove it as they see fit and to modify it within reason with a minimum amount of problems - any consent costs should be kept to a minimum, maybe the cost involved in checking her over to ensure that it remains within the bounds of the specifications consented - in other words it is not changed from a machine that handles 'X'cubic meters per day to one that handles '100X' cubic meters per day. I think that the more sophisticated a machine becomes the more likelihood there is of system failure and especially so when it is required to undergo extensive stress such as moving and processing large amounts of material some of which must surely place stress on the machinery such as when it encounters large boulders which jam the suction nozzle or the bumping and shuddering of larger rocks coming up the intake. To deal with the stress that such a process must invariably place on the machinery it would have to be very robust. A pity - I was hoping that they would have the best of luck but actually did think that they might not achieve the success they expected so I am not surprised that it has failed. In my opinion they might have been better off working an area with smaller rocks and boulders and an area which had not previously been worked - such as the Glenore site. There has to be plenty of virgin sites which could possibly be worked...IF the criminal system allowed it. .

prich385		Posted : Saturday, 27 October 2012 10:49:57 AM(UTC)
Rank: Gold Dust Groups: Registered Joined: 10/10/2012(UTC) Posts: 4 Location: Dunedin Was thanked: 7 time(s) in 4 post(s)		The problems the dredge encountered where the following: 1) Large ammounts of black sand that requires modifications to the sluice system. This was especially true when the dredge was moored down from Pinders pond for a number of months. 2) Depth of the river in some places meaning that the dredge could not recover deep sediment and hence gold bearing material 3) There were some problems with the morring of the dredge due to the currents within the river, meaning access to some parts of the river basin was difficult. There were also a number of days that the river levels were higher than normal due to the warm winter and start of spring. In the later stages of the operation the dredge was going to be moved further towards millars flat as it was thought the river bottom was more uniform. This area has beeen dredged very aggresivley in the past. The operation was postponed not long after this.
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Golddigger7		Posted : Sunday, 28 October 2012 10:57:01 AM(UTC)
Rank: Gold Ingot Medals: Groups: Registered Joined: 6/09/2012(UTC) Posts: 252 Thanks: 1 times Was thanked: 46 time(s) in 35 post(s)		Hey Lammerlaw Sorry but I have to correct you, we aint a police state, were a mafia run state :)

dredgey		Posted : Sunday, 28 October 2012 7:17:20 PM(UTC)
Rank: Gold Flake Groups: Registered Joined: 24/10/2012(UTC) Posts: 11 Location: Takaka Thanks: 1 times Was thanked: 2 time(s) in 2 post(s)		Originally Posted by: simon unfortunately i don't think that suction dredge ever had any luck on the clutha. when i first saw it i thought of the similar one at maori point. it could reach the bottom and i think they found the bottom very clogged with immovable boulders in hard pack. now the joke is they need consent to remove it from the river to run any mods or to remove fully. http://www.odt.co.nz/reg...redging-operation-ceases Maybe the consent is to build a ramp? they had alot of trouble launching it got bogged badly, i would say they will need to construct some sort of a ramp to pull it out. hopefully these guys get it sorted and back in the water still plenty of gold in there... somewhere lol They had numerous problems as expected with a new machine after getting the mechanical issues sorted looks like the recovery system wasnt functioning properly. maybe they need to keep it simple and use a traditional sluice with hydraulic riffles instead of the centrefuges and whatever other methods being used?