A professional who controls equipment to produce alum liquor (aluminum sulfate) in continuous process reaction of sulfuric acid with powdered bauxite. Respnsibilities include:

• Notifies other workers to unload bauxite from boxcars into hopper of crusher.
• Starts crusher, mill, and conveyors to replenish storage supply of powdered ore.
• Observes flowmeters and turns valves to regulate flow of powdered ore, acid, and weak alum liquor into first digester in specified proportions to produce mixture of prescribed specific gravity and through other digesters where chemical reaction occurs and resultant aluminum sulfate liquor is settled and diluted to specified concentration.
• Tests samples from each digester, using hydrometer and thermometer, to verify specific gravities and temperatures.
• Turns valves to adjust flow of steam through digester jackets and proportions of materials fed into first digester to regulate temperatures and specific gravities accordingly.
• Pumps finished alum liquor into storage tank and weak alum liquors into settling tanks (thickeners) for recycling into process.
• Records temperatures, specific gravities, and flow rates of materials in operating log and level of alum liquor storage tanks on inventory records.