Utilize the input text as a context reference, choose the right relationship between Mozal and Maputo from the options. Options: product/material produced, manufacturer, distributed by, industry, position held, original broadcaster, owned by, founded by, distribution format, headquarters location, stock exchange, currency, parent organization, chief executive officer, director/manager, owner of, operator, member of, employer, chairperson, platform, subsidiary, legal form, publisher, developer, brand, business division, location of formation, creator.

The BHP Billiton Mozal smelter, for example, consumes two-thirds of the electricity generated in Mozambique but employs only 1,070 people at its plant in Maputo and 3,500 downstream, with jobs ranging from catering to sewing uniforms, according to its own figures.

Answer: headquarters_location