PUMPS
underwater gold mining uses pumps to suck material to the surface and separate it through sluice boxes . Although somewhat effective , the method has drawbacks including restrictions on production because of lack of pump power and capabilities , lack of versatility , and environmental impact concerns .
The lack of pump power and capabilities largely stems from the type of pumps used . Most operations use centrifugal pumps deployed in an ejectorjet setup , which allows the pumping system to move large solids without clogging and destroying the pump . A conventional centrifugal pump has a small tolerance between the impeller and the volute , limiting what can pass through the pump without getting clogged at the impeller .
Additionally , the constant bombardment of abrasive solids on the impeller affects the tolerances . As a result , the pump suction significantly decreases . In many operations , the equipment is pumping at a rate of about 5 to 10 % solids versus water , and the heavier gold will often fall out of suspension because of lack of suction power .
Another option does not involve a centrifugal , positive displacement or vortex design , but instead an EDDY Pump hydrodynamic pump that uses fluid dynamics . Undersea gold extraction operations are greatly dependent on weather conditions . Wave conditions often make it too dangerous for divers to be in the water or for excavators and dredges to operate . Also , there are large restrictions on the depth of dredging — mainly 10 m or less .
Eddy Pump says its Subdredge “ state of the art dredging system , is unique to the market and is changing how companies mine for gold and perform sediment removal . The dredge pumps that power this unit are also available for slurry transport dredge projects .”
The Subdredge is a remote operated submersible dredge that can be powered hydraulically or electrically with pump sizes ranging from 4 in up to 10 in with production of 306 m 3 / h . The Subdredge can be equipped with an umbilical that allows for it to operate remotely at distances of up to 305 m or greater from the operator . The Subdredge is “ ideal for dredging applications that call for great depths , precision dredging , and unmanned operation .”
All Eddy dredges use its industrial pumps , which are non-clog pumps designed for high solids pumping applications . It says its “ patented pump technology outperforms all centrifugal , vortex and positive displacement pumps in a variety of the most difficult pumping applications .”
Eddy Pump technology uses the principles of a tornado to create a synchronised eddy current , which it says is “ the most highly efficient high solids and high specific gravity pump on the market . This translates to the ability to pump higher percent solids of material and capture the heavy specific gravity gold .”
The submersible dredge uses high-definition cameras and acoustic positioning integrated into a real-time kinematic GPS that allows it to operate virtually blind . The equipment also offers more mining time in all weather conditions . IM