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Pa yc 2 Roger Funston March 12, 1980 As referenced in the Federal preamble disco, ion of section 817.124, owner- ship of structures or Sands does not relieve the legal requirements of protecting the surface en vironment. 1:he .:rppli.rant should indicate the potentially affected structures on map IV-l, or any other appropriate map of his choice. The applicant should then detail, in conformance :ri.th the requirements of 784.20, whether theae structures will be materially damaged. If such damage is anticipated to occur, the applicant wi.Ll have to describe in detail har he intends to mitigate that damage. At a minimum, I anticipate that this requirement will pertain to the structures that comprise Cmpire Village, located in close proximity to one of the areas of past subsidence indicated on map IV-I. 2) In at least two Zocations within the revised application, the applicant observes that he reserves the option .`o Jmprove uoon his design, if operational experience warrants carne. I agree whole-h•eartedly with this intent. In order to justifu amend.men(:s to the approved mine plan, however, accurate data will have to be provided. The application states; "Empire seecifically reserves the right to demonstrate through field data to be gathered in connection with pZannecl subsidence, that mini.ny under streams and renewable resource Zands can be accomolished with no material damage upon the surface, surface water sustems, and the groundwater systems". (ZV-84 8) In ordez~ to accompZ.ish such a demonstration, however, an effective monitoring program will be necessary. The applicant proposes the installation of a monitoring network consisting of 14 elevation stations, indicated on map :(V-1. Ne proposes to survey these stations every six months after the commencement of extraction in the immediate area. This pr. o; ram will produce valuable data dealing with ground surface suhs:denee occurrence. I fear, however, that it will not produce data of sufficient detail to ;;arraat amendment of the permit. I recommend to the applicant the adoption of several sets of nronuments installed in Linear cross section lines above entries and i~anels to be extracted during the early segments of tii~~ mine plan. This would allow careful observation of vertical and horizontal movcr,.ents. Furthermore, the proposed six month frequency of observation may proves to be inadequate. Observation on a higher frequency, perhaps monthly, :could allow observation of possible oscillatory movement with much greater detail. Such a program, conccntr,:'~:rq on several limited areas of interest, should alloy the collection of much more conclusive data. In addition, any structures identified within the areas to be undermined, should be monitored to assure the vali?.'ity of the applicant's predictions concerning material damage. ~.'.O~~OSED f~'T'!E WASTE pI Z,C STABZLZZ}' The revised application contains a response to m_y earlier memoranda's ruestinn=~. The responses indicates the applicant's intent to obtain (cont'd)