MINISTRY OF ENERGY AND MINES Mines and Mineral Resources. REPORT OF GEOTECHNICAL INSPECTOR (Issued pursuant to Section 15 of the Mines Act)

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1 MINISTRY OF ENERGY AND MINES Mines and Mineral Resources REPORT OF GEOTECHNICAL INSPECTOR (Issued pursuant to Section 15 of the Mines Act) Name of Property: Permit No.: M-203 General Manager: Company: Address: Persons Contacted: Copies To: Kent T. Christensen, P.Eng. s Ltd Hastings St W, Vancouver, BC V6C 2W2 Shane Flynn and Randall Thompson Al Hoffman, Chief Inspector of Mines, MEM Diane Howe, Deputy Chief Inspector of Mines, MEM George Warnock, Manager, Geotechnical Engineering, MEM Heather Narynski, Manager, Geotechnical Engineering, MEM Doug Flynn, Senior Inspector of Mines, MEM Scott Parker, Inspector of Mines, Health & Safety, MEM Date of Inspection: August 12, 2014 In this document, Code means the Health, Safety and Reclamation Code for Mines in British Columbia INTRODUCTION A geotechnical inspection of was conducted by the writer and Scott Parker, on August 12, 2014 in the company of employee, Shane Flynn. This report summarizes observations made during the inspection. Inspection orders related to the EPRP were discussed with Messrs Flynn and Thompson following the inspection, and are linked to TMF-3 within this report. The purpose of this inspection was as follows: To determine if the mine is meeting the requirements of the Code and Permit No. M-203. To determine if the geotechnical practices at the mine are consistent with generally accepted engineering practices at mines in British Columbia. To identify potential ground stability hazards or concerns at the mine. To verify the classification of mine dams within the MEM database. The following areas were observed during the mine tour: The Main Zone Expansion Pit. The MZO area of tailings excavation. The NAG quarry. The tailings management cells east of the open pit. The landslide above (north of) the East Cell Tailings. The tailings management facilities immediately west of the open pit (TMF-2). The newly activated tailings management facility (TMF-3). Sediment control ponds SC1 to SC3 and SC5 to SC8. Figure 1, attached, provides the general layout of the Site, other than TMF-3 and SC6 through SC8, which are located west of TMF-2.

2 Report of Geotechnical Inspector August 20, 2014 Page 2 of 11 OBSERVATIONS AND INSPECTION ORDERS Location: Active Open Pit Men and equipment were working in the base of the Main Zone Expansion Pit at the time of the site visit (Photo 1). The radar system used to monitor the high wall (north side of the pit), where slope movements were detected in late 2012, is still active. This system quantifies movements on the basis of changes from previous scans. The results are regularly reviewed by the engineering staff and the extent of the movement zone is now well defined. Movement criteria are in place and alerts are sent out to key mine personnel as soon as any of the key warning criteria are exceeded. It is understood the radar system data currently indicate that a significant wall failure is not imminent. Water management, both surface and ground, is a key factor in maintaining stable pit slopes at Huckleberry. Ditches and horizontal drains which tie into the ditch system have been in place for some time and, based on feedback from Mr. Flynn, have been performing well. Al Chance, P.Eng., of Golder Associates continues to undertake annual inspections in relation to pit slope design and performance. It is understood that Mr. Chance completed a 4-day inspection earlier this summer, i.e. approximately in June. Location: MZO Area As part of the December 2011 amendment to Permit No. M-203, tailings and waste rock deposited previously in the open pit were approved for rehandling and storage at TMF-3. An amendment to Permit No. M-203, dated February 2014, approved changes to the MZO backfill excavation (principally in relation to the tailings) based on the requirement that the recommendations contained in the geotechnical design report issued by Golder Associates in January 2014 are implemented. Observations from the site visit indicated that the transfer of tailings from the MZO to TMF-3 is well advanced. The current base of the MZO excavation is at 958m elevation. Observations of exposed faces within the tailings indicate that, in general, the tailings are well consolidated, i.e. the fine grained material has a stiff to very stiff consistency (see the area highlighted by the red oval in Photo 2). However, in some areas, the tailings have shown a propensity to flow (an example is highlighted by the yellow oval in Photo 2). It is understood that the excavation has been occurring in accordance with the geotechnical design report. Furthermore, Al Chance, who was primarily responsible for the geotechnical design report issued by Golder Associates in January 2014, included an assessment of the MZO excavation and related stability issues during a 4-day visit to site earlier this summer.

3 Report of Geotechnical Inspector August 20, 2014 Page 3 of 11 Location: NAG Quarry The NAG quarry (Photo 3), which is relatively small compared to the main pit, provided non-acid generating andesite as rock fill for the construction of the east cell TSF raise. The quarry has been dormant for an extended period and there are no plans to re-open it. No geotechnical concerns were noted. It is understood that options for potential use of this quarry are being considered. However, there is apparently no defined timeline for any related decisions. Location: West Cell Pond and East Cell Tailings The general layout of the West Cell Pond (Photo 4) and the East Cell Tailings (Photo 5), both of which were part of the East Zone Pit, is illustrated on Figure 1. The East Pit Plug Dam provides containment for the tailings placed previously within the East Zone Pit. Once the starter dam for TMF-3 was constructed and approved for operation, tailings deposition into the West Cell Pond and the East Cell Tailings ceased. At the time of the inspection, water was being pumped to the West Cell Pond (Photo 4). There was ample freeboard on the external south wall of the West Cell Pond. No water was present on the East Cell Tailings (Photo 5). No geotechnical concerns were noted. The Engineer of Record for these structures is Todd Martin, P.Eng., of BGC Engineering Inc. It is understood that Mr. Martin was on site earlier this summer. Location: Inactive Open Pit Slope above the East Cell Tailings The high wall north of the East Tailings Cell that failed a number of years ago is shown in Photo 6. Following the slope failure, a buttress was subsequently installed at the toe of the slope. It is understood that monitoring of this slope is continuing and the data apparently indicates the buttress has essentially stabilized the area. Current plans call for a cover to be constructed over the slide area, from approximately the 1030 level up to the top of the slide scarp. The timing of the cover construction was not discussed.

4 Report of Geotechnical Inspector August 20, 2014 Page 4 of 11 Location: TMF-2 The general layout of TMF-2 is illustrated on Figure 1. Confinement on the west and southwest sides of TMF-2 is provided by the TMF-2 Dam; on the southeast by the Orica Saddle Dam; and on the east by the East Dam. Not shown on Figure 1 is the South Saddle Dam which previously divided TMF-2 from the Main Zone Pit. However, this pit was subsequently filled in. Tailings have not been actively discharged to TMF-2 for some time. A relatively small, shallow pond is present over exposed tailings on the north side of TMF-2, close to the adjacent hill side (Photo 1). A soil cover has been constructed over part of TMF-2 for closure purposes, and waste rock from the active pit is being placed over another part of TMF-2 (Photos 1 and 2). The placement of the waste rock is being done in accordance with a plan developed by the mine staff. The geotechnical stability of the waste rock storage plan is understood to have been assessed, and confirmed as satisfactory, by BGC Engineering Inc. Location: TMF-3 Approval to operate TMF-3 was issued as a permit amendment in July TMF-3 is essentially a sidehill facility situated west of TMF-2 and is the main storage location for tailings associated with current mining and ore processing activities. The main dam segment at TMF-3 runs in an east-west orientation. There is also a short dam segment oriented in a northsouth direction at the west end of TMF-3 that will connect to the main dam as the two dam segments are raised. The design section for the dam consists of a wide till core with filter zones downstream of the core, and granular material as upstream and downstream shells. At the time of the inspection, the starter dam was at elevation 945m and additional rock fill was being dumped against its upstream face (Photo 7). Tailings from the MZO excavation were being placed inside the impoundment, in the area immediately adjacent to the west end of the main dam segment (Photo 7). At the east end of the impoundment, immediately adjacent to the main dam segment, tailings were being discharged into the facility. A pond separated the MZO tailings and the tailings pumped from the processing plant. Away from the current pond, but still within the TMF-3 footprint, rock was being quarried for use in the construction of the dam shell. The Engineer of Record for the TMF-3 is Todd Martin, P.Eng., of BGC Engineering Inc. As noted earlier, Mr. Martin was on site for an inspection of the TMF facilities earlier this summer. On August 12, 2014, one of BGC s field engineers was on site in anticipation of the next round of earthworks construction at the TMF-3 starter dam. The current OMS manual for the tailings facilities was completed in July It includes an Emergency Preparedness and Response Plan (EPRP).

5 Report of Geotechnical Inspector August 20, 2014 Page 5 of 11 A schedule for testing the Emergency Preparedness and Response Plan (EPRP) shall be prepared and submitted to the Ministry by September 5, A summary of the EPRP test including lessons learned shall be submitted to the Ministry within 30 days of the completion of the test along with a schedule for updating the EPRP based on these lessons learned. Note that the EPRP shall be reviewed at least annually and updated as required. Location: SC1, SC2. SC3, SC5, SC6, SC7 and SC8 Downstream of the tailings management facilities are a series of sediment control ponds. For example, Figure 1 shows the location of four small ponds (SC1, SC2, SC3 and SC5) downstream of TMF-2. SC4 (SC4A on Figure 1) is situated downstream of the East Pit Plug Dam. Downstream of TMF-3 are three relatively new ponds (SC6, SC7 and SC8). The design of most of the dams at the sediment control ponds is the same and consists largely of a till embankment with thin shells of rock fill on one or both sides of the embankment. Water from many of the sediment control ponds passes over v-notch weir and into pipes that that direct this water into the channel base immediately downstream of the respective sediment control pond. At the time of the inspection, the water levels in SC6, SC7 and SC8 were very low, having been recently drawn down. No geotechnical concerns were noted. General Observations: The appears to be managing geotechnical risks in an appropriate way. Appropriate methods to manage surface and groundwater at the main pit area are in place. In addition, a high quality system for wall displacement monitoring is in place at the open pit. The dam construction and tailings deposition practices at TMF-3 appear orderly and well managed. Advice is sought from consultant geotechnical engineers on a regular basis. An inspection of the pit slopes is undertaken annually by a senior rock mechanics engineer from Golder Associates. A senior geotechnical engineer from BGC makes at least an annual visit to inspect the TMF s (more frequently than that at present, due to recent commencement of tailings deposition and the incremental construction of the TMF-3 starter dam). It is concluded, therefore, that genuine efforts are made to manage the geotechnical issues on site in a manner which is consistent with best practices. The instruction orders that have been issued with this document are related to testing of the EPRP, and based on "lessons learned," subsequent updating of the EPRP. Lastly, as discussed on site, there is ambiguity in the hazard classification of some of the dams on site. I will contact Shane Flynn with a view to updating MEM s database of dams at (an extension of the related inspection order from 2013).

6 Report of Geotechnical Inspector August 20, 2014 Page 6 of 11 CLOSURE Under Section 15 (6) of the Mines Act, a written response is required from the Mine Manager within 15 days of the receipt of this Inspection Report. The response should be directed to the author, with a cc to George Warnock (George.Warnock@gov.bc.ca) and Heather Narynski (Heather.Narynski@gov.bc.ca). In addition, Section 30 (1) of the Mines Act requires this Inspection Report to be posted in a conspicuous location at the mine site for 30 days. Please feel free to contact the undersigned with any questions or comments. Cameron C.Scott, P. Eng. Geotechnical Inspector Ministry of Energy & Mines Signature Dated: August 20, 2014

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8 Report of Geotechnical Inspector August 20, 2014 Page 8 of 11 Photo 1: Westward view across the Main Zone Expansion Pit. The MZO excavation of tailings (for pit expansion) is visible behind the pit, at the left, and TMF-2 is visible in the background. Photo 2: Westward view across the MZO excavation. Exposed tailings slopes within the red oval are standing up well; those within the yellow oval are showing a propensity to run or flow.

9 Report of Geotechnical Inspector August 20, 2014 Page 9 of 11 Photo 3: Eastward view across the NAG quarry situated to the south of TMF-2. Photo 4: Westward view across the West Cell Pond (taken from the top of the landslide area above the East Cell Tailings).

10 Report of Geotechnical Inspector August 20, 2014 Page 10 of 11 Photo 5: Eastward view across the crest of the starter dam at TMF-3. Photo 6: Eastward view across TMF-2. The Main Zone Expansion Pit high wall and the landslide above the East Cell Tailings are visible on the left and rights sides, respectively, of the photo.

11 Report of Geotechnical Inspector August 20, 2014 Page 11 of 11 Photo 7: Westward view across TMF 3. From left to right are SC8, the TMF-3 starter dam, tailings from the MZO excavation (background) and the area of active tailings deposition (foreground). Photo 8: Westward view along the upstream face of the dam at SC8. Note the low water level behind the dam. The TMF-3 starter dam is visible at the upper right corner of the photo.