Laserfiche WebLink
-42- <br /> monument grid network and a high-resolution cross-grid monument network above <br /> the 5th North Panel off the 8th East Main. This panel will be fully extracted <br /> during the second and third years of the five-year permit period. Data from <br /> this monitoring network will be utilized to verify the subsidence prediction <br /> within the permit application. Subsidence on the order of 4 feet is predicted <br /> to occur above the panel being monitored. <br /> The appli cant was requested to make several amendments in the Division pre- <br /> liminary adequacy review. CWI subsequently has proposed amendments which <br /> have remedied several of the deficiencies satisfactorily, as described below: <br /> 1. In the original application, CWI proposed a semi-annual monitoring <br /> frequency for its subsidence monitoring program. Rule 2.05.6(6) (c) (i) requires <br /> quarterly surveying with semi-annual reporting of the survey results to the <br /> Division. Further, CWI stated in the original application that monitoring <br /> would cease when it determined that no further subsidence would occur. At <br /> the Division's direction, CWI has amended the application to conform with <br /> the quarterly required monitoring frequency (see page 178, Section 2.05) , and <br /> to continue monitoring until such time as CWI and the Division concur that <br /> no further subsidence will occur (see page 180, Section 2.05) . <br /> 2. The proposed quarter section. corner type subsidence monitoring monument <br /> grid network, while it is a worthwhile program for overall observation and <br /> is encouraged, was not judged sufficient to verify projections of angle of <br /> draw. For this reason, CWI was requested by the Division to install a high- <br /> resolution cross-grid type network of monuments above a panel to undergo <br /> total extraction early in the mine plan. CWI has proposed the installation of <br /> such a monument network above the 5 North Panel off the 8th East Main (see <br /> Map 28B) . This network consists of monuments spaced at .1 times the average <br /> depth of overburden above the panel and arranged in a cross-grid pattern to <br /> allow observation of axial and transverse angles of draw. This panel is <br /> believed typical of panels to be developed in this mine plan in that it is <br /> oriented roughly north-south- and is overlain by steep topography (see cross- <br /> section on Map 28B) . <br /> 3. The applicant was requested to utilize a monument construction capable <br /> of resisting normal traffic and climatic extremes (frost-heave) . Because of <br /> inaccessibility, CWI has requested approval by the Division to use a simplistic <br /> rebar monument. CWI believes that because the panel monument system is on a <br /> South facing slope that frost-heave will not disrupt the monuments. Further, <br /> CWI has stated it's willingness to install additional bedrock anchored monu- <br /> ments to serve as a cross-check to determine whether the monument design is <br /> resisting frost-heave disruption for approximately one year prior to <br /> extraction of the monitored panel. To assure completion of this proposed <br /> program to determine adequacy of the monument program, the Division has <br /> developed the following stipulation: <br /> THE OPERATOR IS DIRECTED BY THE DIVISION TO INSTALL THE MONITORING NETWORK <br /> SHOWN ON MAP 28B ABOVE THE 5 NORTH PANEL OF THE 8TH EAST MAIN PRIOR TO <br /> NOVEMBER 1, 1981. IN ORDER TO DETERMINE THE ADEQUACY OF THE SIMPLISTIC <br /> MONUMENT PROPOSED FOR USE IN THIS NETWORK, THE APPLICANT SHALL INSTALL <br /> APPROPRIATE BENCHMARKS TO ALLOW QUARTERLY MONITORING OF THE MONUMENT <br />