We ran serveral buckets of black sand through this muchine over 3 days. It recovered the smallest specks of fine gold from the beach sand. There were some smaller casting rough spots at the middle where we needed to take a file to it and smooth out to get better dropping of the finner specks into the catching cup. However, the frame and braces all bent slightly from the weight of the sand. The concept is great and you will like it's recovery rate.