OUR BLACKSANDS

Otago Daily Times, Issue 22368, 15 September 1934, Page 10

OUR BLACKSANDS

TO THE EDITOB

Sib, —The writer for the last three years has tried to help the unemployed gold miners of Otago and Southland by informing them where we left alluvial gold, and—of more importance to them—where 1000 better miners than myself cleaned up the gold years ago at their own expense. In 1889 we tried an experiment to save alluvial floating gold in fine blacksand. Our run of boxes was 144 feet, the fall seven inches to 12 feet throughout, with coconut matting below ripples of steel bars rivetted to inch angleiron lengthways. In the last 12 feet box ripples were rivetted on crossways to form an undercurrent clear of the matting, where only blacksand and fine material could pass through. Stones and rough wash passed over the top. An old miner convinced us of our loss of floating gold in the fine blacksand. Three feet from the top of the last box he cut a slot eight inches by one inch level with the bottom, provided with a tin slide to adjust the outfall, which discharged on to a side table six feet by three feet, with a fall of one foot in six. On this table he placed coconut matting three feet from the end of the box. Each table was provided with a stream of clean water under pressure from a perforated pipe at the head of each box. This helped to settle the fine blacksand and floating gold. All side tables were washed up once in 24 hours into separate tubs without stopping work on the main run. The copper plate on the side table was renewed once a week. The result of this experiment for two months was a gold receipt for £6 19s. Gold at that time was valued at £3 17s per ounce. We considered we did not treat 1 per cent, of the blacksand that passed down the boxes. Wherever this experiment has been tried in public hydraulic companies or on up-to-date dredges, the writer has never seen as poor a sample as in our own claim. If it will pay to save blacksand our West Coast beaches are the places to be worked. —I am, etc., F. Daw. Oamaru, September 13.