APPARENT ESCAPE OF ACIDIC SOLUTION AT OWB-4 Elevated SO 4 is - PowerPoint PPT Presentation

SULFURIC ACID AT PTF H 2 SO 4 • SO 4 MAKES IT SULFURIC • H 2 MAKES IT ACID • EC MEASURES SULFATE • pH MEASURES ACIDITY INDIRECTLY • FCI STARTS AT pH = -1.22 • FCI STARTS AT 1.6 MILLION mg/l • INDICATOR pH = 6.5 • INDICATOR = 750 mg/l WILSON-1

APPARENT ESCAPE OF ACIDIC SOLUTION AT OWB-4 Elevated SO 4 is evidence of H 2 SO 4 Drop in pH is evidence of H 2 SO 4 WILSON-2

W ILSON’S POC’S DO NOT COST $1.75 MILLION X – POC well per ADEQ guidance x x Would give maximum x x early warning x x x Average direction of GW flow POC-8 WILSON-3 Temp APP Vol. 2, Attach 12-Compliance with AWQS, Figure 12-1 Curis Response to ADEQ RFI, 9/21/2012, Figure 14A-37

SPATIAL BIAS NEAR PTF WILSON-4 Brown Plate 79-2

“OUTSTANDING” CALIBRATION? WILSON-5

CALIBRATION WITHOUT AVERAGING WILSON-6

ASSUMPTIONS MATTER WILSON-7 MODEL-6

ADEQ SAYS NO NEUTRALIZATION AGENTS WILL BE USED WILSON-8 Responsiveness Summary, July 5, 2013, Page 100 of 332

POTENTIAL HEALTH EFFECTS based on Material Safety Data Sheets Consideration Lemon Juice Sulfuric Acid Eye May cause irritation Severe burns, possibly irreversible Skin Low hazard Burns Ingested Low hazard Severe and permanent damage Inhaled Low hazard Severe irritation, burns, tissue damage Chronic None May cause death Exposure response Rinse, get medical Rinse, get medical aid attention if irritation immediately, CPR if develops breathing has ceased WILSON-9

BADCT: HYDRAULIC CONTROL AND RESTORATION Definition of Hydraulic Control in the application for a temporary permit (page xvi): Inward hydraulic gradient that prevents in-situ solutions from migrating beyond portion of oxide zone where injection and recovery of in- situ solutions is occurring. WILSON-10

Section 3.4.4.2 BADCT GUIDANCE ON SHORT-CIRCUITS [Exhibit Southwest Value Partners 156, page 3-41] “Potential for short circuiting of anticipated solution migration pathways due to fractures and solution/rock chemical reactions over time is a potential concern that should be assessed for in-situ mining in most instances”. WILSON-11

MONITORING IN OBSERVATION WELLS (JULY, 2012) WILSON-12 HC-20 Email Request & Response- ADEQ (JW) to Curis (MN, DJ), 7/24/2012, pg. 3

NEW OBSERVATION WELLS North 30 gpm Add these 60 gpm wells 30 gpm 60 gpm 60 gpm 30 gpm West 60 gpm 30 gpm WILSON-13

CALCULATE AND REPORT H 2 S0 4 BALANCE H 2 SO 4 H 2 SO 4 Extracted Injected H 2 SO 4 consumed H 2 SO 4 in solution in ore body H 2 SO 4 not accounted for WILSON-14

72’ EXCLUSION ZONE IS MISLEADING (1) Steel casing Fiber glass Cement Cement casing 40ft Exclusion Zone 72ft 32ft to top of screen Fiber glass to PVC coupling Gravel & PVC sand screen WILSON-15 filter Temp APP, Vol 1, Attachment 9, Exhibit 9A, Drawing 9A -1, March 1, 2012

72’ EXCLUSION ZONE IS MISLEADING (2) Steel casing Fiber glass Cement Cement casing 40ft Exclusion Zone 72ft 32ft to top of screen Uppermost Gravel & PVC injection to = sand filter screen gravel and WILSON-16 sand filter Temp APP, Vol 1, Attachment 9, Exhibit 9A, Drawing 9A -1, March 1, 2012

72’ EXCLUSION ZONE IS MISLEADING (3) Steel casing Fiber glass Cement Cement casing 40ft Exclusion Zone 72ft 32ft to top of screen Uppermost Uppermost = injection to injection to = gravel and Oxide Zone WILSON-17 sand filter Temp APP, Vol 1, Attachment 9, Exhibit 9A, Drawing 9A -1, March 1, 2012

PMA PER STATUTE PMA PMA “Pollutant Management Area”: ‘… the limit projected on the horizontal plane of the area on which pollutants are or will be placed” (A.R.S §49-244(1)). In other words, the land surface location that represents the source of the pollutant. Illustration taken from ADEQ public presentation on Hydrogeologic Requirements for APPs, given by Mason R. Bolitho, July 15, 2010 WILSON-18

SIDE VIEW OF WHERE PTF MAY PLACE POLLUTANTS Limit of where pollutants may be placed WILSON-19

PMA PER CURIS PERMIT WILSON-20

SIDE VIEW OF APPROVED PMA Limit of where pollutants may be placed WILSON-21

PMA THAT CIRCUMSCRIBES DISCHARGING FACILITIES WILSON-22

HYDRAULIC CONTROL BARRIER DESIGNED WHERE 1 FOOT INWARD GRADIENT REQUIRED = inward gradient of 1 ft. WILSON-23

APPROPRIATE LOCATIONS FOR COMPLIANCE WELLS WILSON-24

TIMEFRAME FOR POC CAPTURE WILSON-25

RINSING FLOW SHEET WILSON-26

VERIFY ARSENIC MODEL USING BHP DATA WILSON-27 Produced from BHP Database, FlorenceDB.mdb

COMMITMENTS TO PROOF OF CONCEPT • Regulation R18-9-A210: may apply for a temporary permit for a pilot project to “ develop data for an APP application for the full- scale project .” • Curis Letter referring to deficiencies in full-scale application : “Pilot test facility will allow for development of data to respond to ADEQ’s request for additional information dated September 7, 2011.” • Curis Application for Temporary Permit: has five purposes including (2) develop data for the pending APP application for commercial – scale ISCR operations. • Temporary Permit: authorizes Curis to construct and operate a production test facility which shall provide sufficient data to assess and develop a full-scale in-situ mining operation. WILSON-28

ADEQ’S ACTUAL POSITION ON PROOF OF CONCEPT ADEQ Response page 189 of July 5, 2013 response document ADEQ believes there is sufficient monitoring in the permit to verify data assumptions, eliminate uncertainties and detect excursions of mining solutions. Quarterly PTF Operational and Monitoring Reports will be submitted in accordance with Section 2.7.4.4. ADEQ considers the data provided in the Quarterly Reports as a proof-of concept validation (PTF system performance, groundwater gradient information, groundwater sampling and monitoring well sampling data, etc.) throughout the PTF monitoring period, in addition to a PTF Summary Report required at the cessation of rinsing. WILSON-29

BIMODAL DISTRIBUTION OF HYDRAULIC CONDUCTIVITY Theim Golder WILSON-30

A. 18 gpm injection produces mound > 100 feet high B. 21 gpm injection produces mound < 30 feet high A B WILSON-31

Importance of PTF heterogeneity (1) Well layout comparable to PTF layout [PTF Observation and multi-level wells not shown] WILSON-32

Importance of PTF heterogeneity (2) Enlargement of well layout comparable to PTF layout WILSON-33

Importance of PTF heterogeneity (3) Heterogeneity: short-circuits occur “This feature indicates that there is a short circuit between BHP-5 and BHP-9. The wellfield is separated into two somehow isolated areas.” BHP-3 BHP-4 CH-1 CH-2 BHP-10 BHP-12 BHP-1 BHP-5 BHP-2 OWB-4 BHP-9 BHP-13 WILSON-34 Hydrogeological Studies For the In-Situ Leach Field Test at Florence, Arizona, pg. 24

Importance of PTF heterogeneity (4) Hypothetical short circuit at edge of commercial mine LOW CONDUCTIVITY ZONE SHORT CIRCUIT WILSON-35

Importance of PTF heterogeneity (5) Many possibilities for short-circuits to occur at edges of commercial project WILSON-36

Plume size varies with assumptions WILSON-37

ARROWS BASED ON FLOW MODEL, NOT TRANSPORT K=1 K=0.57 K=0.1 WILSON-38