632-030-0023 Aggregate Mining on High Value Farmland in the Willamette Valley (1) For the purposes of this rule, the following definitions apply: (a) “Significant aggregate resource” means the average minimum depth of aggregate, determined by rule of the Land Conservation and Development Commission, that is required for a local government to find that the aggregate resource is significant pursuant to a statewide land use planning goal that protects natural resources and conserves scenic, historic and open space resources. (b) “Substantially all” in the context of this rule means; approximately 90% of the significant aggregate resource anticipated to be available for excavation at the time an application is submitted to DOGAMI, or approximately 90% of the significant aggregate resource actually found within all or a specific portion of the approved excavation area. (c) “Thickness of the aggregate layer” means the depth of the water-lain deposit of sand, stones, and pebbles of sand-sized fraction or larger, minus the depth of the topsoil and nonaggregate overburden. (2) This rule applies to the following: (a) Applications for new operating permits when all of the following circumstances exist: (A) The applicant proposes to mine an aggregate resource, (B) The proposed mining operation is located within the Willamette Valley, (C) Excavation for the proposed mine will disturb high value farmland composed predominately of Class I and Class II soils; And (D) The area where the proposed mining operation will be located has been listed as a significant aggregate resource site by the local government with jurisdiction and the listing is based in part on the thickness of the aggregate layer pursuant to the rules of the Land Conservation and Development Commission OAR 660-023-0180. (b) Applications for amended operating permits for mine sites where this rule is already applicable, or where the amendment proposes to expand the excavation area onto land not already approved for mine excavation when all of the following circumstances exist: (A) The applicant proposes to mine an aggregate resource, (B) The proposed mining operation is located within the Willamette Valley, (C) Excavation for the proposed mine will disturb high value farmland composed predominately of Class I and Class II soils; And (D) The area where the proposed mining operation will be located has been listed as a significant aggregate resource site by the local government with jurisdiction and the listing is based in part on the thickness of the aggregate layer pursuant to the rules of the Land Conservation and Development Commission OAR 660-023-0180. (3) An operating permit for a mining operation subject to Section (2) of this rule must require the operator to excavate substantially all of the significant aggregate resource, except in any of the following areas: (a) Areas designated as buffers or setbacks established in the operating permit, (b) Areas needed to meet sloping requirements in the operating permit or reclamation plan, (c) Areas where aggregate removal is limited by other operating permit requirements or permit conditions that are imposed to protect health, safety, or the environment; And (d) Areas where aggregate removal is limited by the requirements imposed under the regulatory authority of a federal agency, local government, or other state agency. (4) Before the Department issues a new or amended operating permit subject to Section (2) of this rule, the applicant must demonstrate to the satisfaction of the Department that the applicant has the mechanical ability to comply with the requirements established in Section (3) of this rule. An applicant must demonstrate mechanical ability to comply with the rule by providing the following: (a) A detailed plan describing the equipment, techniques, and order or sequence of mining operations that will be used to complete the excavation of substantially all of the significant aggregate resource except where excavation is limited as provided for in Sections (3)(a) – (3)(d) of this rule. The plan may be based on geotechnical borings, geophysical surveys, direct observations, or other methods acceptable to the Department; And (b) Include a detailed contour map showing the proposed geometry of the excavation area following the removal of the significant aggregate resource throughout the mine site prior to the placement of any proposed reclamation backfill material. (c) The plan required under Sections (4)(a) – (4)(b) of this rule does not require the applicant to address the excavation of aggregate below the depth of the significant aggregate resource. (5) The Department will not approve partial or final reclamation, including final closure of an operating permit subject to this rule, unless the operator has demonstrated compliance with Section (3) except where excavation is limited as provided for in Sections (3)(a) – (3)(d). If any portion of the excavation area is proposed to be backfilled as part of the reclamation plan, the permittee must demonstrate to the Departments satisfaction that the significant aggregate resource has been removed in compliance with Section (3) of this rule prior to the placement of any reclamation backfill material. Documentation of compliance with Section (3) of this rule must be submitted to the Department for approval prior to the Department considering any partial or final reclamation including final closure of the operating permit. The documentation must demonstrate, to the satisfaction of the Department, the final excavation depth throughout the mine site, including individual mine cells, and removal of substantially all of the significant aggregate resource in compliance of Section (3) of this rule. Documentation may include but not be limited to: (a) Post mining bathymetric surveys, excavation logs, or other documentation of adequate resolution and precision acceptable to the Department, in cases where mining resulted in a water filled excavation pit; Or (b) Remote sensed data, topographic surveys, or other documentation of adequate resolution and precision acceptable to the Department, in cases where mining resulted in a dry excavation pit. Statutory/Other Authority: ORS 517 Statutes/Other Implemented: ORS 517.825 History: DGMI 1-2021, adopt filed 09/20/2021, effective 10/01/2021