There are other methods that are now emerging. In the Philippines they are using Borax with the flux method. I don't know if this method will work in Guyana. Guyana like Alberta and Montana has flour gold now near the surface. The larger pieces of gold near the surface are gone. Dug up by miners in the past. Only deeper gold mining can now get larger loads of gold and only large companies with capital can go deep. I calculated a small size gold mining operation in Guyana not using mercury will take at least one million us dollars to get started. Plus money to sustain the operation until you find gold. You better find gold in the first six months or else you going belly up and stormborn will have to piggy back you back to Georgetown.