I have used one somewhat like the one in your picture. You simply hook one or two horse to it with a single or double tree. Use a handle in back to set the angle of dig and have the horse step up. Once loaded angle the slip back to carry the material to a stockpile. At the stockpile, angle the slip down so that it catches and the horsepower will flip it effectively dumping the load.
In my area thes things are being sold as lawn ornaments for rustic/fancy homes at a good price.