Dresser Trap Rock, Inc. | The Hardest Rock For All Your ...
About Dresser Trap Rock. Established in 1914, Dresser Trap Rock Inc. continues as one of Wisconsin's oldest industries. The company name originates from the kind of rock being crushed on loion: trap rock, which is a dark, finegrained igneous rock. Known as one of North America's hardest rock, trap rock is actually altered basalt, or ...