World resources of phosphorus

The geochemistry of phosphorus and the global distribution of its resources are reviewed. The concept of reserves and resources is discussed in view of recent price developments in the phosphate mining industry. A description is given on the application of a model called MIMIC (Mining Industry Model for Inventorization and Cost evaluation of mineral resources) for estimating the inferred global reserves and resources in different cost categories. Based on the size and growth rate of annual production, the inferred reserves can be estimated at +/- 20 000 Mt of phosphorus. This figure is in reasonable agreement with conventionally estimated demonstrated resources. Estimates of exploitable resources with the MIMIC model vary between 40 000 and 500 000 Mt with about 20 000 Mt in deposits containing about 14% P (70% BPL). The inferred reserves alone would satisfy current consumption for many hundreds of years. In this context, the historical growth rate of slightly less than 7% per annum appears neither exceptional nor particularly alarming with respect to the next doubling of the world population.