Space is a different environment from any that we have ever experienced on earth. On earth certain things can be ignored or discarded and they will simply be reabsorbed by the world until a use is found for them. Living in space doesn't afford the luxury of waste. As new industries and products are created that use the resources of space they must take a comprehensive view of how to use those resources.
Space mining will be one of the first to experience the need for total resource utilization as it will be the one of the first product-based industries in space. (satellites are a service-based industry)
Not all of what is mined from asteroids will need to be dropped to earth to be used. As it stands now the only thing worth dropping are the precious metals. But some of the other useless minerals will likely be turned into spacecraft, and large asteroids may be hollowed out to be turned into ships or space stations. But these processes are energy and engineering intensive. Another way could be created that would be used to create space real estate. All the left over materials could just be thrown into a pile with a little glue.
Masses of land could be built, with very little effort, from the debris left from space mining. From that, settlers and organizations could set up habitats on the bodies. These large bodies could have the benefit of special configurations and orientations. they could be built as large disks which can always face the sun, allowing access to a large energy source. They could become space docks. They could even be used as resorts.
This post post is meant to draw attention to a use for the useless. Space mining will have waste. When an asteroid is stripped and ground up, many of the minerals will not be worth saving or transporting, unless a use already exists.
This is simply a heads up that one man's waste is another man's resort island.