Centerra Gold Inc.

Sampling, Analysis, and Data Verification

Knowledge regarding sample preparation, assaying, and sample security during the exploration and development phases of the Thompson Creek Mine deposit by Cyprus (1968 through 1981) is based on historical reports from Cyprus and The Winters Company. The Winters Company completed numerous checks and reviews of the pre-2000 drillhole database as part of contracted work for TCM in 2000.

The following presents a summary of the procedures that were utilized by Cyprus for most of their exploration programs:

The Cyprus data were collected prior to the more rigorous quality assurance and quality control (QAQC) practices of today. Cyprus did a certain amount of check assaying between different laboratories and was able to make various comparisons between drillhole samples and bulk samples collected from underground developments driven into the orebody. Despite the lack of robust analytical quality control data support of assay data, the mine has produced a significant amount of molybdenum. Since 1998, the mill processed approximately 123 million tons (111.8 million tonnes) of ore, producing approximately 247 million pounds (112,000 tonnes) of molybdenum. Throughout most of the mine life, the long-range geological model was based primarily on the Cyprus drillhole data, and it correlated adequately within the expected variance from production data for tons and grade. This fact suggests that the historical data are generally reliable, and that they can be used for mineral resource estimation purposes.

For most of the post-Cyprus drilling campaigns completed during the years 1997 to 1999 and 2007 to 2009, sample preparation and assaying was completed at the Thompson Creek Mine laboratory. That lab did not obtain ISO certification. However, the laboratory operates to industry standards and serves several third-party clients that trust the laboratory’s data quality. Assays from drill programs since 1997 include molybdenum, lead, iron, uranium, and sulfur. Analyses for the latter elements were obtained to ensure the quality of the molybdenum concentrate and not for potential metal recovery.

The sample protocols at the Thompon Creek Mine laboratory were:

The blast-hole data were also assayed onsite at the Thompson Creek Mine laboratory. Samples were assayed for molybdenum and lead, and every fifth sample was analyzed for iron if the molybdenum grade was above the cut-off of 0.030% Mo. Waste samples were assayed for sulfur, and every fifth sample was assayed for molybdenum. Blast-hole data have been lost and thus were not available for review.

According to Thompson Creek Mine staff, the core and reverse circulation samples were assayed for molybdenum, copper, lead, and iron at the Thompson Creek Mine laboratory. The Thompson Creek Mine geologic staff did not submit standard reference materials (SRMs) at source; however, the Thompson Creek Mine lab introduced their own SRMs according to their standard protocols. The TCM laboratory also inserted blank material in assay batches as part of their internal QAQC.

After the assays for the 2007 drilling program were completed, the Thompson Creek Mine sent 138 pulps to the Skyline laboratory located in Tucson, Arizona, to be assayed for molybdenum. The samples were selected based on initial waste, low-grade, and high-grade molybdenum values. These samples represented a frequency rate of about one check assay per 12 original samples.

In addition to the external laboratory checks discussed above, the Thompson Creek Mine collected duplicate samples from their 2007 core and reverse circulation drilling campaigns. The mean grades for the first and second duplicates vary between +3% and -8% from the original or initial sample grades.

Analytical QAQC procedures for the 2008, 2009, and 2010 drilling campaigns were restricted to the Thompson Creek Mine onsite lab protocols. The mine prepared SRMs from blast-hole cuttings. These SRMs have an expected grade of approximately 0.074% Mo with two standard deviations ranging between 0.068% and 0.080% Mo. The most recent standard, known as “QC#9”, was routinely inserted into the atomic absorption instrument at a frequency of one standard for every five samples after the machine was calibrated with a blank. In-house SRM is considered acceptable in this case, considering the lack of commercially available material. No assay certificates are available for post-2009 drilling.

Based on the above discussion, the Thompson Creek Mine drillhole data are considered representative of the molybdenum mineralization at Thompson Creek and thus are suitable for the purpose of Mineral Resource estimation. The TCM has had extended periods of production with favorable reconciliation history of prior resource models and production results.

The prior QPs, Marek and Lechner (2011), had a long working relationship with the Thompson Creek Mine. In 1997 and 2000, numerous checks were made between the electronic drillhole database and the Cyprus drillhole assay logs, downhole survey logs and lithologic logs. In general, the electronic database was accurate with few errors. It is noted that the Thompson Creek Mine had been operating for over 15 years at the time those data verifications were made and that the Thompson Creek Mine typically experienced excellent reconciliation results.

Since acquiring the property in late 1993, Thompson Creek Mining Company LLC and later Thompson Creek Metals Company Inc. (2006) have drilled approximately 129 drillholes totaling around 115,258 feet (35,130 metres). Most of this footage was drilled as infill data for mine planning purposes and the rest was for geotechnical and dewatering purposes.

The QP responsible for this in the TCM Technical Report did perform basic data validation on the 10 holes completed in the post-2009 drillhole campaigns. Those validations were based on comparing the new drillhole results to surrounding holes and where available, reviewing various QAQC results.

The same drillhole database (with the inclusion of the post-2009 drillhole data) and long-range block model that were the basis of the last Technical Report (Marek and Lechner, 2011) have been used for the TCM Technical Report. The Thompson Creek Mine used the June 2010 block model until the mine closed in late 2014 due to low metal prices.

The Thompson Creek Mine and mill operated from 1983 through to 2014, during which period metallurgical characteristics and operational processes of the ore were well established. The ore is processed through a gyratory crusher, a SAG-ball mill (SAB) circuit, and combined with rougher and cleaner flotation plant, to produce molybdenum-rich concentrates. The mine and concentrator were placed on care and maintenance in December 2014 when the mining and processing of Phase VII ore was completed.