Asphalt milling machines have been around for over 30 years. Asphalt milling is the process of grinding up asphalt

Asphalt

Asphalt or , also known as bitumen, is a sticky, black and highly viscous liquid or semi-solid that is present in most crude petroleums and in some natural deposits, it is a substance classed as a pitch...

 that can then be recycled. The process came about because many streets were getting higher and higher on curbs, and therefore drainage of the roadway was becoming an increasingly bad problem. The first production milling machines were called Galions after their manufacturer, Galion Iron Works

Galion Iron Works

Galion Iron Works is the name of the company that build Galion brand construction equipment. World famous for their graders that shaped the roads of the world, a saying emerged that "All roads lead to Galion." They also manufactured rollers, cranes, asphalt millers and even riding sqeegees among...

. These machines resembled grader

Grader

A grader, also commonly referred to as a road grader, a blade, a maintainer, or a motor grader, is a construction machine with a long blade used to create a flat surface. Typical models have three axles, with the engine and cab situated above the rear axles at one end of the vehicle and a third...

s in shape and size. The difference was there was a 30 inches (762 mm) milling head where the scraper blade would normally be. The cutter drum was set into action by a rather large hydraulic pump.

Today's machines are much larger. They also have elaborate conveyor systems to reduce the labor of picking up the material from the roadway. With many new types of asphalt aggregates in use today the asphalt cold milling machines are often used. These new production machines are designed to tackle any mix design they chew into. Some of the larger machines, depending on the depth of the cut, can cut close to 15000 square yards (12,541.9 m²) a day, at 75 feet per minute.

Operating an asphalt milling machine requires specialized training. Typically newer machines require two or more people to operate safely and efficiently. The operator stands on the deck of the machine and controls most of the machines functions, while another person on the ground controls the depth of the cut and keeps an eye out for obstructions in the roadway such as manholes and/or water valves. Operators typically learn by on-the-job training, making the transition from operating on the ground to running the machine on top.

Diamond grinding of pavement is a process to work the surface of asphalt or concrete pavement.