A repository of task structures can reveal important latent knowledge about the development of a software system. Although approaches have been proposed to recover artifacts within a task structure, identifying relations that are relevant to a task remains a problem. In this work, we propose to detect "interaction coupling" from task interaction histories (i.e., records of when the artifacts were being used or modified in a task, as observed by the IDE), and use this information to mine patterns to aid in the comprehension of maintenance activities. In our case study, we found we were able to recover latent information about the development process; for example, our results suggest that restructuring is more costly than any other maintenance activity.