A practical localization technology for underground drift networks—such as those excavated in the practice of underground mining—has yet to become commercially available. This paper focuses on the problem of mapping GPS-deprived underground environments with the eventual goal of using these maps for navigation. Recent industry-directed work in the creation of a landmark-bounded occupancy grid mapping tool that combines odometry, scanning laser data, and sporadically placed passive RFID tags is described. Unlike other work, the suggested approach holds the philosophy that precise localization of the actual landmark locations is not necessary; rather, landmarks serve as a global means for partitioning the map. Successful field experiments were conducted in two underground environments, with the results used to conduct a basic analysis of the described method. © 2012 Wiley Periodicals, Inc.