Progressing process plant projects from studies to construction and operations requires process design work, preliminary engineering and metallurgical studies to prove up an economic flow sheet and plant layout. This work has a reliance on basic sampling, ore characterisation, and metallurgical testing to a standard that supports sound decision-making. Often overlooked and underappreciated is the role of collaboration and multidiscipline approach employing best practices and attention to detail play to maximise the economic extraction of metal. This paper will present examples of sampling practises often observed for copper development projects and compare these against sampling practises considered the best, with supporting evidence. Some of the benefits and pitfalls of domaining practises and tests used for comminution and flotation characterisation will be discussed for a selection of copper case studies. Copper projects developed by Sedgman using these best practises have demonstrated a substantial uplift in net present value (NPV) by domaining of ores by different comminution and flotation characteristics. The details of one such project will be presented that yielded a 27 per cent increase in the size of the resource and 29 per cent increase in project scale. The domaining also resulted in significant changes to the comminution and flotation circuit design, maximising the economic extraction of metal. A second case study details the importance of comminution and flotation sampling in combination with geospatial considerations. These considerations enabled a new operating schedule to be proposed which resulted in a 34 per cent uplift in copper production over the first four years of the project, significantly increasing the overall project value. The case studies presented demonstrate the importance of best practise with respect to sampling, ore characterisation, domaining and metallurgical testing to support the design basis, and technical and economic viability of copper development projects