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View Full Version : Dewatering a pit?



geowizard
09-01-2012, 11:17 AM
Everyone that has operated a mining operation knows there is no shortage on "mining consultants". All of the neighbors want to come around offering free management advice!

Ok, so, who has all of the solutions to all of the mining problems in the world?

Well, a couple years ago, while pondering the many options of suction dredging, it became apparent that a closed pit would offer immediate solutions to most of the issues with suction dredging. A large closed pit offers manageability of water in the sense of having a settling area and organizing flow from intake to settling area - back to intake.

- Geowizard

overtheedge
09-01-2012, 04:43 PM
Visibility could become an issue.

One possibility if the pit has enough surface area is to trough the tails water to the far end and use some sort of dike system to make a serpentine recycle circuit. Perhaps blue tarps hung like set nets.

You are exactly correct about solutions geowizard. Sometimes it takes a collaborative effort and some outside-the-box thinking to find a possible answer. That is the great thing about forums like this. Info was in short supply back in the 70's and 80's.
eric

thegoldgopher
09-01-2012, 08:30 PM
Two things: On the first season of Gold Rush, they had a pit type situation, and they had a problem with the intake being buried by silty mud. I would have put it on a pontoon arrangement in the center of the pond, which is what I think they did. Second, when I built a trailer mounted recirculating water sluice, I used a 110 gal. or so galvanized stock tank for a recovery tank for used water. After so many runs, particularly when we hit clay, the dissolved silt became a problem by turning almost gelatinous in nature. Might a pit do the same thing after a few times of the entire volume being recirculated, and the various very small particles stratifying?

geowizard
09-02-2012, 05:41 AM
Not all silt is created equal.

Silt that is primarily organic can "have a life of it's own" so to speak. Muck as it is commonly referred to is bad news for a mining operation. It is usually stacked and replaced when surface remediation takes place. Silt that is inorganic i.e. fine shale material will settle and not become gelatinous. I will dewater the pit and use the Bobcat to stack the silt that has settled which formed a mud flat. Run off and seepage that comes in clear, refills the pit and mining continues if suction dredging is the option.