Data mining is much more than simply building statistical models from large collections of data. In particular, this paper records a core task of mining as exploring through the space of models that are built in a data mining project. The idea was first introduced through the concept of multiple inductive learning (MIL) (Williams, 1988, 1991) and further developed in practice as mining the data mine (Williams and Huang, 1997). Many data mining advances that have since emerged have further developed the idea: multiple modelling, ensemble learning, bagging and boosting all help the data miner explore different ideas and look for different insights in modelling. In this paper we review these ideas and a number of data mining projects that highlight the significant role played by mining the data mine.