Laserfiche WebLink
JAMES A.BECKWITH <br /> FONTANARI OBJECTIONS AND COMMENTS/SNOWCAP BOND APPLICATION SL-1 I /PG. 2 <br /> The Study Area contains valuable basaltic material located to a depth of 50-60 ft. <br /> below the surface. The amount of rock (including large boulders) limits the surface use to <br /> seasonal livestock grazing and wildlife habitat. Snowcap's Permit and Reclamation Plan <br /> acknowledges these established uses of the Study Area. <br /> B. SL-11 concerns lands with a history and continuing presence of subsidence. <br /> It is well known that, in room-and-pillar mining, the collapse of tunnel roofs due to the <br /> removal of pillar support during retreat mining causes surface subsidence. Room-and-pillar <br /> mining including retreat mining was performed in the Study Area for well over one <br /> hundred years.' This occurred in the Old Mine Workings (pre-1980) and New Workings <br /> (1980-2000). Collapsed tunnels from both mining eras exist beneath the Study Area. <br /> Surface subsidence (tension cracks; voids and depressions) have been present in the <br /> Study Area for nearly as long. Mr. Jeff E. Magers of the United States Bureau of Mines first <br /> noted tension cracks on Tract No. 70 In 1981-85.2 (Magers Report; Pg. 12; Figs. l 0-11) <br /> Those cracks merged or evolved into one tension crack 200 feet long and up to 9 feet deep in <br /> 1991. (Id.) By 2016, this massive tension crack again evolved into a continuous line of deep, <br /> major sinkholes. DBMS' recent August 2018 inspection revealed the continued existence of <br /> these sinkholes on Tract No. 70 as well as the presence of new and additional sinkholes in <br /> both the northeast corner of Tract No. 70 as well as areas south of the 2016 sinkhole line. It <br /> further revealed sinkhole lines along the western wall of the canyon on the tract's eastern <br /> border. This latter area has suffered significant slumping in years past, with more current <br /> slumping creating a bench 75 feet below the canyon's rim. This slumping is above an area in <br /> which, in 1992 Powderhorn Coal Company recorded a lengthy north-south line of collapsed <br /> tunnels. (Fontanari Exhibit 2) <br /> As another example of the presence of subsidence, on Tract No. 71 surface water <br /> migrated through the old Mine Workings and into the South Portal via surface sinkholes <br /> bordering two subsidence depressions in 2014. Inspection of Tract No. 71 in 2016 revealed <br /> the continuous existence of these two large depressions, as well as numerous sinkholes <br /> bordering the edge of each depression. Those findings were reported to DRMS in October <br /> 2016. DRMS' recent August 2018 confirmed the continued presence of both the depressions <br /> 1 Coal mining beneath Tracts Nos. 70 and 71 began as early as 1888: when J.P. Harlow and <br /> George Crawford first obtained a Coal Certificate and U.S. Patent for the southwest corner of <br /> Sec. 341, T 1 OS, R98W. (Fontanari Exhibit 3) Local historians refer to the "Harlow Mine" as <br /> the pre-cursor of the "Roadside Mine". The 1980 GEx Mine Map locates the original Harlow <br /> Mine adit, or portal, at the north end of this plateau. <br /> Surface Subsidence over A Room-arid-Pillar Mine in the Western United States; Jeff A. <br /> Magers; United States Department of Interior; 1993 Hereafter, referred to as "Magers Report". <br /> A copy of this Report is contained in Tab 10, Snowcap Application. <br />