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Mount Carbon Metropolitan District Job No. 1-1107-6292-00 -2- records indicating that 20 tons of coal were removed between 1934 and 1936. The Bluebird Maps seem to include the workings of the previous Satanic and Sharon Mines. The Bluebird workings are mapped for more than 1,800 feet southeast along strike from the location of the shaft, shown on figure 1, attached. The workings are up to 950 feet in depth. five pit-like subsidence features were noted south of Alameda Parkway on the City of Lakewood park property in the southwest corner of Section 24. The pits are linearly oriented, generally along strike. The two southernmost depressions are thought to correspond to the locations of the Bluebird hoist shaft and portal. Evidence of surface workings of the Rooney-White Ash Mine is visible north of Alameda on the same bearing. No distress was noted in the Alameda Roadway. These subsidence depressions were the only ones noted on the parcel and are almost certainly related to the various shafts necessary to service the mines. No evidence of large-scale collapse of underground work- ings was noted, although some of the maps indicate that mining took place within 50 feet of the surface near Alameda Parkway. The theoretical subsidence trough profile on the parcel would start at the western edge of the coal seams in the Laramie and extend far to the east under the park property. The areas of maximum possible subsidence would be over the strike trace of the coals and for several hundred feet just to the east of the known depressions. The probability of mesurable subsidence to the west of the coal seam from mining within the seam is exceedingly remote. Any possible subsidence at the surface would be mast likely from the shallow workings of the mines and very much less likely from the deep workings due to bridging effects of deep overlying hard sedimentary layers and bulking effects as voids fill in from below. For example, subsidence expected from a ` :00 foot deep extracted seam would be much more than the same thickness of extraction much deeper. As further regards the alignment of McIntyre Street onto the park parcel as shown on maps supplied to this office, a further concern is brought forth. The mesa associated with the Chieftain Clay Surface Mine is quite steep-sided and during the spring of this year, a significant landslide mass has moved off the hill, nearly into the proposed alignment. We recommend that if the roadway is to pass close to the toe of the mesa, the mesa be cut back in benches to a safer overall slope. We have found that Alameda Parkway was originally built by the City of Denver as an access road to Red Rocks Park in the 1930's. It is doubtful if special considerations were taken in its design as it crosses the Rooney-White Ash However, it can be assumed that for a proposed alignment of a major atertial such as McIntyre Street to cross an area known to contain obvious subsidence features and subject to the most probable future subsidence, a very high level investigation would be recommended to show how the roadway could be built over the shallow workings and continue to be safe for travel. We are of the opinion that such a detailed investigation would be expensive and may