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Individual APP Applications Individual APP Applications Best Available Demonstrated Control Best Available Demonstrated Control Technology (BADCT) Technology (BADCT) for Facilities other than other than for Facilities Wastewater Treatment Plants Wastewater Treatment Plants Vimal Chauhan Vimal Chauhan 1 October 21, 2010 October 21, 2010

ARIZONA MINING GUIDANCE MANUAL BADCT (Publication # TB 04-01)  Process of selecting BADCT in accordance with A.R.S. 49-243.B.1.  All permitted facilities shall utilize BADCT in the design, construction and operation.  A.A.C. R18-9-A202(A)(5) requires that an APP application include a description of the BADCT for the proposed facility. 2

BADCT Selection Process Overview  Use demonstrated discharge control elements • To demonstrate BADCT, a facility must be evaluated in terms of: 1. Discharge characterization 2. Siting 3. Design, construction, and operation 4. Closure and post-closure 3

Determination of BADCT  Key concepts of the manual are: • BADCT must be determined on a site specific basis. • No single technology or group of technologies can be mandated as appropriate for all discharge control systems. • NOTE: The Demonstrated Control Technologies (DCTs) presented in the BADCT manual are simply alternatives. • Monitoring is generally not regarded as part of the BADCT design. 4

The BADCT Process  BADCT determination process involves deciding whether to use: • “Prescriptive” approach Or • A site specific “Individual” approach  Both approaches have the same goal of preventing, or minimizing to the maximum extent practicable, the loading of pollutants to an aquifer. 5

Prescriptive BADCT Criteria  Objective: To simplify and expedite the permitting of conventional facilities by: • Minimizing required information gathering • Adopting an approved design • Limited information review • Limited negotiations 6

Prescriptive BADCT Criteria – cont.  The Prescriptive BADCT Criteria provides the following: • Use of a predetermined DCT as the BADCT design. • Simplified method to propose acceptable BADCT. • Generally conservative, hence minimizes the level of site investigation and engineering evaluations. • Based on the premise of minimizing any discharge beyond the engineered containment. Therefore, natural attenuation is not a consideration. 7

Individual BADCT Criteria  The Individual BADCT Criteria provides the following: • Allows evaluation of alternative discharge control (ADC) systems which combine site characteristics with DCTs. • Provides a method to utilize a site specific BADCT design. • Allows BADCT design to be optimized compared to the generally conservative Prescriptive BADCT criteria. 8

Prescriptive BADCT (Section 1.1.1)  Designed to be generally conservative for most site conditions.  Includes specific design criteria for many of the BADCT elements. However, engineering equivalents may be acceptable (see Table 2-1 of the BADCT manual).  NOTE: Engineering equivalents cannot rely on seepage attenuation or other geologic properties of the vadose zone as part of minimizing aquifer loading.  ADEQ may require specific supporting evaluations for the proposed element. 9

Prescriptive BADCT – cont.  Facilities eligible to utilize the Prescriptive approach: • Non-Storm Water Ponds (seepage or contact stormwater from a tailing impoundment, waste dump, process area, etc.) • Process Solution Ponds • Heap Leach Pads • Tailing Impoundments 10

Prescriptive BADCT – cont.  Conditions affecting the use of Prescriptive BADCT approach: • Facilities located in areas of shallow groundwater. • Facilities located in areas prone to excessive subsidence. • Facilities located in the vicinity of active faults. • Facilities located in landslide prone terrain. • Facilities located in other locations of known geologic instability. 11

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Individual BADCT Review Process for New Facilities (Section 1.1.3)  Definition: "New facility" means a previously closed facility that resumes operation or a facility on which construction was begun after August 13, 1986 on a site at which no other facility is located or to totally replace the process or production equipment that causes the discharge from an existing facility.  Only general guidance is provided for the development of an Individual BADCT design process, since it follows the general principles of engineering design. 14

Individual BADCT Review Process for New Facilities – cont.  The application shall include a statement of the technology which shall describe the following: • ADC measures considered • Advantages and disadvantages of each alternative • Justification for selection or rejection of each alternative 15

Individual BADCT Review Process for New Facilities – cont.  The applicant shall evaluate: • Each alternative DCT relative to the amount of discharge reduction achievable. • Site specific hydrologic and geologic characteristics. Provide demonstration through modeling or data collected during the application process. • Other environmental impacts. • Water conservation or augmentation considerations. 16

Individual BADCT Review Process for New Facilities – cont.  Important aspects of developing an Individual BADCT design are: • DCTs constitute a discharge control system incorporating engineering features, operational measures and site characteristics to achieve BADCT. • Alternative designs must be considered to arrive at a BADCT design. 17

Individual BADCT Review Process for New Facilities – cont.  The BADCT design is developed through the following approach: • Develop a range of ADC systems • Screen the ADC systems based on the relative degree of discharge control • Select the best ADC systems for further analysis • Refine designs for the selected ADC systems • Estimate discharge control for the selected ADC systems • Selection of BADCT design 18

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Individual BADCT Review Process for New Facilities – cont. Site Selection  The design documents submitted for APP permitting must describe the site selection process.  Site selection can be performed in a formal or informal process. • Formal Process: The preferred site will be selected through a process of: o Fatal flaw screening o Site evaluation and ranking o Limited site investigations and final ranking (in some cases) • Informal Process: This process is often necessary because of limited availability of suitable sites in the vicinity of the ore body (proximity to the plant area/processes). 21

Individual BADCT Review Process for New Facilities – cont. Development of Reference Design  The following must be considered: 1. Industry-wide DCTs taking into account differences in industry sectors 2. The type and size of the operation 3. The reasonableness of applying controls considering the site climatic conditions 4. Other site specific conditions  A systems approach should be used which considers all phases of the project including: 1. Site characterization 2. Design, construction and operations 3. Closure and post-closure 22

Individual BADCT Review Process for New Facilities – cont. Development of Reference Design – Cont.  For example, in developing a Reference Design, site specific DCTs should be included such as: • Selection of a site with low permeability geologic formations • Specific design elements such as: – Use of single synthetic liners – Specific operational technologies such as maintaining the low hydraulic head on a leach pad – Specific operational monitoring proposals such as regular inspections by the facility operator – Specific closure and post-closure technologies such as bacterial rinsing for a gold heap leach pad 23

Individual BADCT Review Process for New Facilities – cont. Estimation of Aquifer Loading  An evaluation must be performed to estimate the potential loading of pollutants to the aquifer. At a minimum, the following steps shall be followed in performing this evaluation: • Estimate the potential release from the facility. • Estimate the travel time of a pollutant to the water table • Estimate attenuation of pollutants in the foundation or vadose zone • Estimate aquifer loading of constituents including but not limited to those that have established water quality standards  However, keep in mind that it is not intended that this evaluation should turn into a research project. 24

Individual BADCT Review Process for New Facilities – cont. Alternative Design(s) Selection  This can include the evaluation of alternative control technologies or design elements for each applicable type of facility, or, as may be appropriate, the evaluation of alternative sites. 25