'Threshing floors' in the Bible

And they told David, saying, Behold, the Philistines are fighting against Keilah, and are robbing the threshing-floors.

Then the iron, the clay, the brass, the silver, and the gold, was broken in pieces together, and became like the chaff of the summer threshing floors. And the wind carried them away, so that no place was found for them. And the sto