Cone sumps 1

[ruble3]

We are investigating using cone sumps ( rather than trditional cleanwater/dirty water decant sumps)- the plan is to divert the water to the top of the cone, and clear water decants off to the clean water sump- the 'fines' will settle to the bottom of the cone & will be drawn off into'slime cars' - has anyone experience with measuring the density in the 'draw-off' pipe- can the density get so thick it won't flow into the cars ? the material isn't flowing so I don't think a nuclear gage would work but not sure what else might be out there- looked at Solatron but don't know if that would work either? weightometers on side of cone like a measuring bin?

 

[CanuckMiner]

A couple of years ago I worked on a cone settler design for a mine in Northern Manitoba. The design there drains the slimes periodically to a batch tank which in turn feeds (pumps) the slimes to a filter press. The filter press "dries" the solids somewhat and the filter cake is conveyed to the ore bin.

Pressure transducers were located at the bottom of each of two settling cones. These are used to measure the approximate average density of the fluid above (i.e. calibrated for water, then the data was extrapolated for the solids content). When the conditions were right (i.e. approximately the right overall density), a pinch valve at the bottom of a cone would open, and a nuclear density gauge is used to measure the density of the slimes as they pass. If the density drops below a setpoint (i.e. too thin), the pinch valve closes before delivering a full batch.

The system is reportedly working well (commissioned a couple of months ago) when they remember to add new bricks of floc at the top of the cone. I imagine there would be (and will continue to be) some "teething pains" as they adjust the pressure/density setpoints to suit their duty.

Incidentally, I had heard that they did indeed plug one of the cones because the slimes thickned too much and wouldn't run without a bit of "incentive".

Cheers,
CanuckMiner

 

[ruble3]

Thanks Canuckminer- I think I know exactly which property
your refering to- are the 'cones' steel or just excavated in rock& shotcreted? Our plans( as far as I know) are for
an excavation & shotcrete- they plan on using a pd pump at the bottom of the cone, and pump into a car or large bin- if we just use a shotcreted excavation I guess I won't be able to use transducers-I had mentioned the filter press but I think the $$ might have scared them, plus with the cone, the feeling is the water will be clean enough our pumps can handle it
Can you keep in touch- will probably have more questions!
Thanks

 

[CanuckMiner]

The pressure transducers I was referring to are on the draw off pipe (above the pinch valve location) so I think you could use a similar arrangement.

The cones were excavated as alimak raises and then fabricated stainless steel cone bottoms were installed at the raise bottom.

The total installation was indeed pricey, but the Owner had a project manager who really pushed for it. As you know, slimes handling is always an issue at a mine but it usually isn't possible to present an economical case for a capital intensive system (even allowing for labour costs, LHD maintenance, etc.). One added feature of putting the dried slimes back into the ore circuit is that IF the slimes grade, there is a tangible payback.

How will a pd pump help at the bottom of the cone? Won't gravity pretty much be doing the work to fill your car/bin?

If you have further questions, ask away and I'll do my best to respond.

Cheers,
CanuckMiner

 

[ruble3]

Canuckminer: I'm not sure why the pd pump at the bottom of the draw off pipe- I assume becuase the original layout didn't allow for access directly under the pipe- I'll ask the engineering outfit if we really need it or not- I thought we were going to put in steel of some kind at the cone bottom ( stainless or whatever but doesn't sound like it)- I think they are planning on excavating & shotcreting- being in maintenance and not 'operations' I would think over a number of years the shotcrete would deteriorate? I'll have to ask
thanks for your input