Abstract: The disclosure is directed to a grab bucket suspended from the cable of a hoisting means. The hosting means includes a first reversible motor drive means to raise and lower the grab bucket and a second motor drive means is associated with the grab bucket for opening and closing the bucket. Pursuant to the invention, a slack line limit switch is arranged and configured to detect a slackening condition in the cable as when the bucket reaches a pile of material. Upon said slackening condition, the limit switch operates to stop the first reversible motor drive means and to start the second reversible motor drive means to commence the closing of the bucket.