The milling process consists of using a milling machine to scrape off the top layer of asphalt to a specific depth. Once the asphalt is scraped off the remaining asphalt is swept clean and an asphalt tack emulsion is applied. Asphalt tack is a glue that is activated by heat. Once the tack is layer down a new layer of asphalt is paved over the milled surface, compacted and striped. All “millings” that are loaded into trucks from the milling machine are brought back to the asphalt plant to be made into new asphalt.