From the following website: http://www.sctrails.net/Trails/how-to/tools.html
A mattock is a sturdy grubbing tool with an adz blade that can be used as a hoe for digging in hard ground. The other blade of a mattock may be a pick (pick mattock) for breaking or prying small rocks or a cutting edge (cutter mattock) for chopping roots. Mattocks may be purchased with head weights ranging from three to six pounds. For heavy work, use at least a five-pound head. Handles are generally 36 inches long, a good length for almost all trail work. The head should tighten on the handle as the mattock is swung, but sometimes it loosens and slides down the handle. To keep the head in place, put a small sheet-metal screw into the handle just below the head. The handle can be removed for ease in packing.