Wish I had a $ for every kilo of REEs I have put back it the rivers and pits in Sierra Leone. Or better yet wish I had stockpiled them. Main focus was Gold and Diamonds, there was no Market for the REEs (the dirty) after you had extracted the fine gold. To process it further and extract the powder gold was too expensive (cost of chemicals etc:)and would DESTROY the REEs. The need for most mining companies to produce and become self financial as soon as poss is a must. It was profitable for companies to pay me to dredge and mine for Gold in SL when it was $300.00oz and they never thought it would hit $500.00.
Let me put it this way, Remove the OVERBURDEN,(goes straight back into river) and then PROCESS the TOP SANDS and GRAVEL down to CONCENTRATES with the SLUICE,( light materials back into river and HEAVY MINERALS in lower box and Sluice. Clean Sluice and Lower Box, Transport to land, (usually by boat) Dry, Pick or extract gold and stockpile REEs.
VARIABLES:
DEPTH of WATER.
PUMP HEAD.
DEPTH of OVERBURDEN and TYPE.
SKILLS.
USE of LOCAL KNOWLEDGE.
WEATHER.
Doone seems to have a wide and accurate knowledge of this company and the area they are in.
The short answer would have been YES, YES, NO.
Hope this is HELPFUL
Dredgemaster