International Atomic Energy Agency inspectors employ several safeguards measures to ensure only declared operations are occurring at a gas centrifuge plant. One safeguards tool, environmental sampling, can help quantify the materials present in a cascade and gas centrifuge plant. The sampling results can be compared with expected values to determine if the concentrations found are reasonable. In this paper, a methodology is presented for determining the operating envelope of isotope enrichment and material throughput that can be achieved in a reduced throughput cascade. The effects of feed material and centrifuge performance and optimization are studied.