With critical minerals firmly on policy, investment and industrial agendas, attention is turning from strategy to delivery. Technologies are being advanced through field trials, pilots and demonstrations, supported by corporate, strategic and public capital. Yet technical validation is not evidence that a technology will scale, attract customers or become financeable. It establishes performance under defined conditions. Bankability requires more. Drawing on experience investing in early-stage technologies across the mining and minerals value chain, from exploration and extraction through processing, refining, recovery and recycling, this paper examines what must be proven beyond technical validation for a technology to scale. The route differs materially by technology. Exploration platforms, sensing and equipment technologies, processing routes and first-of-a-kind refining projects require different validation pathways, commercial models and forms of capital. There is no single critical-minerals scale-up model. What is consistent is the need to solve a material problem and create sufficient value to justify the cost, disruption and risk of adoption.