A professional who operates one or more mixing machines to combine tar, asbestos fiber, asphalt, or similar ingredients to make roof coating and cement. Respnsibilities include:

• Starts mixing machine and pump and opens line valve to admit asphalt into mixing machine.
• Observes indicator or measuring stick and stops asphalt flow when specified amount has entered mixing machine.
• Dumps specified ingredients through well into mixing tank or starts conveyor and dumps ingredients onto conveyor leading to mixing machine.
• Reads ammeter to determine consistency of mixture and adds materials as needed, or visually determines when mixture has attained consistency and stops mixing machine.
• Draws off sample of mixture for laboratory testing.
• Turns lock bolts to open lines between mixing tank and storage tank, using wrench.
• Keeps record of batch made, including deviations from written formula.