2019-10-22_REVISION - C1981041 - Laserfiche WebLink

Home Browse Search

,LAMES A.BECKWITH FONTANARI OBJECTIONS AND COMMENTS/SNowCAP BOND APPLICATION SL-1 1 1 PG. 10 In 1996, Powderhorn incepted its Mine Dewatering System. This is a critical element of the abandoned tunnels under Tract No. 70. Unconsumed mine water was stored beneath Tract No. 70 as a "sump" and then released, first through outflow 002 and, after 2000, then through Outflow 016 (located in Fontanari Tract No. 23). This history is undoubtedly the reason for at least three major surface subsidence expressions shown on Mr. Eldridge's 2018 Updated Survey. (Fontanari Exhibit 17.) First, during the 2018 bond release inspection a single line of rocks, running east-west across the plateau and down its eastern slope, was noted. This is an area where in years past GEx hired Fontanari to bulldoze over a surface tension crack. (Fontanari Exhibit 18.) This is not a former roadway, as has been previously suggested. The photographs clearly reveal only one crest, most likely created by bull-dozing earth into each side of the tension crack, and rocks piling on top. There is no indication of another crest of rocks (or a depression caused by vehicle tires) parallel to this crest, which would be the standard indicator of a roadway. Notably, the line of these rocks goes straight to the water hole found in Subsidence Event G, below. Second, a line of sinkholes was first cataloged by Fontanari in 2016 along the same line as Mr. Magers' 1985 "six stress cracks." (Fontanari Exhibit 19.) They are shown on Mr. Eldridge's 2016 Plat and his 2018 Updated Plat. This line of sinkholes runs east-west across the plateau and down its eastern slope. (Exhibit 9.) Mr. Hernandez tested the slope sinkholes, finding them to be 24 inches or more deep. Mr. David Fox, P.E., and water engineering consultant to Fontanari, tested the plateau sinkholes, finding one at 24 feet deep. (Fontanari Exhibit 20.) Third, another stress crack, coupled with a line of sinkholes, was found southeast of the second line of sinkholes. (Exhibit 9.) These holes were also 2-3 feet deep and situated not far from the crest of the plateau's slope. This line of sinkholes was not found in Fontanari consultants' April 2016 inspection of Tract No. 70. It was found only in 2018. Subsidence Event G 1 Tract No. 70 Central DRMS' last transect was of the smaller plateau in the northeast corner of Tract No. 70. On this tract Mr. Magers had installed four subsidence rods as part of his "D Line," all of which appeared on Mr. Eldridge's 2016 survey plat. On August 16, Messrs. Hernandez and Bowles found and logged two new sinkhole lines. (Fontanari Exhibit 21.) These sinkhole lines were not present during the April, 2016 site inspection by the Fontanari consultants. On August 24, 2018, Fontanari agents revisited the Subsidence Event locations. An additional sinkhole was found along the Haul Road at the location of Subsidence Event G. The previous night there had been a rain shower. Surface water flowed downslope and into this sink hole: which measured at a 3 feet minimum depth. (Fontanari Exhibit 22.) The hole borders a large borrow pit, (id.),but the water flowing into the hole did not reach that pit.