material streams

We are working on a project where there is not enough room for on-site separation, and the commingled waste will be picked up by the sorting facility. This facility will conduct sorting on their site post removal and will be responsible for tracking the diversion from the landfill by weight of materials. The sorting facility will also provide a receipt of project specific materials and weight of each project specific material stream that they were able to divert to their recycling partners. I understand that this is an acceptable approach for counting material streams. For instance if the sorting facility sends a 100 tons of concrete and 90 tons of metal to the same recycling facility, we should be able to count these as 2 streams? The recycling facilities, however will not provide project specific waste tickets.