Submitted By Mike From Surrey. Thanks for the post Mike.
As I am a firm proponent of Sample! Sample! Sample! I wanted to do a simple test to see if I was losing any gold through dry classification. I dug 4 buckets of unclassified material for my test.
This first photo shows the 4 pails, 2/3’s full.
The second photo shows the dirt being classified down to 1/2 inch.
This third pic shows the material after dry classifying to 1/2 inch.
I then proceeded a step-by-step process of classifying the material:
1.) First dry classifying the material down to 1/2 inch.
2.) Wet classify down to 1/4 inch with bucket classifier and pan.
3.) Wet classify further to 1/8 inch.
4.) I hand panned down the 5 gallon pail of 1/8 inch minus.
5.) Then I washed all the 1/2 inch plus material left over from the dry classification.
6.) I panned the dirt from the dry classified material.
The results actually startled me. There was gold in every pan! What startled me the most was the gold left on the rocks after dry classifying to 1/2 inch. The lesson learned here is if dry classifying (obviously wet classification is preferred, but not always possible), do NOT through your rocks away. There is gold on them. While not a lot of gold was found on the dry classified rocks, when you consider how much material you move in any given day, it adds up.
Keep on digging and have fun!