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Memo to Boulay Jumbo Mountain Landsliding page 7 valley, the Division has repeatedly expressed a concern regarding the possible reactivation of ancient, historic and modern landslides by subsidence during mine permit review. This same concern is commonly expressed by land owners and the public. The Division has included permit conditions requiring every mine with mapped landslide deposits above projected subsidence to monitor the stability of known landslide deposits to determine whether any reactivation were to occur. The Bear Mines and the West Elk Mine were both required to monitor known landslides adjacent to the town of Somerset. while these landslides subsided several feet no landslide translational reactivation has occurred. The Orchard Valley mine (Bowie #1) was required to monitor known landslides in Stevens Gulch and adjacent to its Portal facilities. None of these landslides evidenced reactivation. These same requirements have also been placed on underground coal and hardrock mines in other areas of the State of Colorado. To date, while they have been subsided, none of the monitored landslides have evidenced any reactivation. At the same time, every one of these mines has continued to evidence landslide occurrence, both in and outside subsided areas within the permit and adjacent areas. The North Fork Valley of the Gunnison River has evidenced periods of extensive landslide activity, in response to abnormal meteorological conditions, specifically during 1983-1984, 1993- 1994 and 1996-1997. I anticipate that if the El-Nino related precipitation is significant in 1998, it will be an active landsliding period, as well. Based upon this experience, I conclude that subsidence does not appear to have been a significant determinant in the reactivation or initiation of landslide activity in the North Fork Valley. Land Use Implications of Landsliding The Jumbo Mountain north slope landslide complex is transected by the boundary between Gunnison and Delta Counties. The county line appears to bisect the Muffler Rock landslide scarp. To determine the County land use designations for the property in question, Mike Boulay of the Division contacted the Planning Directors for both Delta County (Ms. Barbara Ball) and Gunnison County (Ms. Joanne Williams). In Delta County there are no zoning requirements or land use designations. However, there are special zoning districts, but none of the Mautz property is located within any of these areas. There are no zoning designations in Gunnison County either. Joanne Williams determined that the Mautz property is designated as an "agricultural use by right" in Gunnison County.