Surplus Ore Potential as a Scarcity Indicator for Resource Extraction

Summary The importance of increase in the scarcity of resources can be assessed using different approaches. Here, we propose a method that is based on the amount of extra ore mined to assess the importance of the extraction of resources. The surplus ore potential (SOP) indicator quantifies the extra amount of ore mined per additional unit of resource extracted by applying log‐logistic cumulative grade‐tonnage relationships and reserve estimates. We derived SOPs for 18 resources (17 metals including uranium and phosphorus) with 5 orders of magnitude difference (between 4.1 × 10 −1 kilograms [kg] of extra ore per kg of manganese extracted and 5.5 × 10 4 kg of extra ore per kg of gold extracted). The sensitivity of the SOP values to the choice of reserve estimates (reserves vs. ultimate recoverable resource) are within a factor of 3 of each other. Combining the SOP values with the 2012 global extraction rates of these 18 resources resulted in a 236 to 372 kg ore /capita surplus ore extracted. Iron, phosphorus, copper, gold, and aluminium were the largest contributors. The large variation in SOP values we observed between resources emphasizes the potential relevance of including resource‐specific SOP values to assess the contribution to resource scarcity by specific products and technologies.