Analyze the relationship between 'Mozal' and 'Maputo' within the context of the input sentence.
Options: headquarters location, platform, chief executive officer, distribution format

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.
headquarters location