Detour Gold Provides Updated Life of Mine Plan for Detour Lake

TORONTO, ONTARIO--(Marketwired - Mar 22, 2017) - Detour Gold Corp. (TSX:DGC) ("Detour Gold" or the "Company") is pleased to announce an updated life of mine plan for its Detour Lake operation located in northeastern Ontario.

All dollar amounts are in Canadian dollars unless otherwise stated. US$ refers to United States dollars. Totals may not add due to rounding.

Updated Life of Mine Plan

A National Instrument 43-101 technical report (the "Technical Report") for the updated life of mine ("LOM") plan will be filed today on SEDAR (www.sedar.com) and posted on the Company's website (www.detourgold.com).

Highlights

• Proven and probable open pit reserves of 16.5 million ounces contained gold
• Average annual gold production of approximately 656,000 ounces over LOM
• Mine life increased to approximately 23 years
• LOM total site costs¹ of US$758 per ounce sold
• After-tax NPV5% of $3.7 billion, using long-term gold price of $1,562/oz (US$1,250 at a 1.25 exchange rate)

Paul Martin, President and CEO, commented: "The updated LOM plan responds to our near-term permitting constraints and provides achievable targets by drawing on our experience to date while offering significant upside potential to improve operational experience. The Detour Lake mine operation remains a unique asset within the mid-tier producers with its long life, relatively low costs and robust economics."

Updated Life of Mine Plan

As disclosed in the Company's news release dated January 30, 2017 ("Updated West Detour Development Plans"), the Company modified its LOM plan for the Detour Lake operation as a result of permitting uncertainties associated with the West Detour project. The updated LOM plan includes the following key elements and results:

• Accommodates for the timing of a federal review process for permitting (if required)
• Annual mining rate increase to 125 Mt with additional mine equipment
• Annual plant throughput maintained at 23 Mt starting in 2021
• Near-term increase in strip ratio with 2019-20 average annual gold production below 550,000 ounces then increasing significantly above 700,000 ounces in 2021-22
• Total site costs increased to US$758 per ounce sold, an 8% increase from the prior LOM plan

¹ Total site costs include production and operating costs such as mining, processing, site general and administration, bullion shipment, refining, agreements with Aboriginal communities, capital costs (including closure costs) and net of silver sales.

Key Inputs from LOM Plan

Operating Plan

The mine production plan assumes the continued development of the Detour Lake pit with the start-up of the North pit in 2019 and the West Detour pit in 2025. The processing of low grade fines ("LG Fines") represents an additional source of ore and contributes to achieving a plant throughput capacity of 23 Mt.

The mining rate for the Detour Lake pit gradually ramps up from 100 Mt in 2017 to 125 Mt in 2022. During this period, the strip ratio will vary annually from 3.6:1 to 6.6:1 (excluding North pit). The ultra-class haulage truck fleet is projected to increase from the 32 CAT 795 trucks in 2017 to 38 in 2022 (plus allowance for 2 additional trucks if required) with the addition of two shovels (beyond the current two electric rope shovels and four hydraulic shovels). The fourth hydraulic shovel was fully assembled in March 2017 and is now operational.

The development of the West Detour pit is now scheduled to commence in 2025, ramping up to a maximum mining rate of 35 Mt per year. It assumes initial contractor pre-stripping followed by a combination of small equipment and shared usage of the Detour Lake pit fleet. The Company plans to use the West Detour pit, once depleted, for tailings and/or waste rock deposition.

The development of the North pit is scheduled to start in 2019 using a contractor (at a maximum rate of 7 Mt per year due to the small size of the pit), which provides flexibility for either an earlier start-up under a provincial process or a delayed start-up under a federal process. In the second scenario, the plant feed would be supplemented by LG Fines and/or lower grade material until the permit is received. Once depleted, the pit is planned to be used as a mine water pond during the operations.

The Company will continue to stockpile material grading between 0.40 to 0.50 g/t Au (referred to as mineralized waste or low grade material, which is estimated at 98 Mt averaging 0.45 g/t Au over the LOM) in order to process the LG Fines. In the LOM plan, the processing of LG Fines commences in 2019 at a rate of 0.5 Mt, increasing to 2.3 Mt in 2020 and consistently at 1 Mt per year in 2021+.

The LOM mine plan assumes a gradual ramp-up of the processing plant capacity, from 21.5 Mt in 2017 to 23 Mt in 2021+ (22 Mt or 60,000 tpd from run-of-mine and 1 Mt or 3,000 tpd from the LG Fines).

Compared to the prior LOM plan, the main impact on the production plan is an increase in the strip ratio over the next five years (representing an increase of 40 Mt of waste) as a result of the delayed start-up of the West Detour pit. Over 2019-2020 period, the ore from the Detour Lake pit is supplemented with LG Fines (mentioned above), resulting in an overall 9% decline in gold production compared to the prior LOM plan.

Summary of the mine production plan (shown as yearly averages per period):

Site Operating and Capital Costs

The most significant changes in site operating costs from the prior LOM plan are:

• A 10% increase in mining costs over the LOM ($2.65/t vs $2.41/t mined) mainly as a result of higher diesel consumption rates, higher maintenance costs, additional support equipment, and use of contractors for the North pit and West Detour pre-stripping activities; and
• A 4% increase in milling costs over the LOM ($8.53/t vs $8.24/t milled) primarily related to higher maintenance and shutdown costs.

Approximately 75% of operating costs are Canadian dollar denominated.

Sustaining capital costs over the LOM are estimated at $2.5 billion, approximately 34% or $640 million higher than the prior LOM plan. The increase from the prior LOM plan primarily reflects the following:

• An increase of $280 million in mining equipment maintenance due to an assumption of a higher frequency of major repairs and component replacements (based on current experienced costs) and $87 million from additional mine equipment and water management;
• An increase of $172 million for the construction of the tailings facility due to the starter dam design change (for both Cell 2 and 3), higher reliance on contractors, and the extended mine life (2 additional lifts); and
• An increase of approximately $100 million for the processing plant ($35 million) and infrastructure ($65 million)

Total site costs over the LOM are projected to average US$758 per ounce sold compared to US$701 per ounce sold in the prior LOM plan.

Summary of operating and capital costs:

Economic Sensitivity Analysis

The economic cash flow model, based on a long-term gold price of US$1,250/oz and a US$/C$ exchange rate of 1.25, generates an after-tax net present value (NPV) at a 5% discount rate of $3.7 billion.

The economics of the Detour Lake operation are most sensitive to changes in gold price, the Canadian and US dollar exchange rate and mine operating cost changes.

The sensitivity analysis shows that:

• A $100/oz gold price change impacts the after-tax NPV5% by approximately $800 million
• A $0.20/t mining unit cost change impacts the after-tax NPV5% by approximately $200 million

2016 Year-end Mineral Reserves

Mineral reserves at December 31, 2016 were 530.2 Mt at 0.97 g/t containing 16.5 million contained ounces. A gold price of US$1,000 per ounce at a US$/C$ exchange rate of 1.10 was used in the reserve estimate (unchanged from 2016 LOM plan). The increase from year-end 2015 is primarily attributable to modified modeling parameters and positive infill drilling results from the North pit, offset by 2016 mining depletion. The complete mineral reserve and resource statement can be found at the end of this news release.

Qualified Persons

A NI 43-101 compliant Technical Report will be filed today on the Company's website and on SEDAR. For further information or details regarding technical information associated with the Detour Lake mine and development of the West Detour project, refer to the Technical Report. The report was prepared by the Detour Gold Technical Services Department, led by Drew Anwyll, P.Eng., Senior Vice President Technical Services, a Qualified Person under National Instrument 43-101. Mr. Anwyll has reviewed and approved the content of this news release.

The mineral reserve and mineral resource estimates for the Detour Lake operation (except for the North pit mineral resources) were prepared under the supervision of Drew Anwyll, P.Eng., Senior Vice President Technical Services and the mineral resources for the North pit were prepared by Paul Daigle, P.Geo, of P. Daigle Consulting Services, both Qualified Persons as defined by Canadian Securities Administrators National Instrument 43-101 "Standards of Disclosure for Mineral Projects".

Workshop Presentation

The Company will host an analyst workshop tomorrow, Thursday, March 23, 2017 at 9:00 AM E.T. to discuss the results of the updated LOM plan. The event will be webcast and the accompanying presentation will be available on the Company's website www.detourgold.com.

Webcast and presentation:

• Go to www.detourgold.com and click on the "Webcast" link on home page
• Presentation (pdf) available on home page

For further details on this event, contact Sandy Noyes, Investor Relations Associate, at (416) 309.7345.

About Detour Gold

Detour Gold is an intermediate gold producer in Canada that holds a 100% interest in the Detour Lake mine, a long life large-scale open pit operation.

Detour Gold Corp., Commerce Court West, 199 Bay Street, Suite 4100, P.O. Box 121, Toronto, Ontario M5L 1E2

Mineral Reserve and Resource Tables (Effective December 31, 2016)

Information Concerning Estimates of Mineral Reserves and Resources
These estimates have been prepared in accordance with the requirements of Canadian securities laws, which differ from the requirements of United States' securities laws. The terms "mineral reserve", "proven mineral reserve and "probable mineral reserve" are Canadian mining terms as defined in accordance with NI 43-101 and the CIM Definition Standards. The CIM Definition Standards differ from the definitions in the United States Securities and Exchange Commission ("SEC") Guide 7 ("SEC Guide 7") under the United States Securities Act of 1933, as amended. Under SEC Guide 7, a "final" or "bankable" feasibility study is required to report mineral reserves, the three-year historical average price is used in any mineral reserve or cash flow analysis to designate mineral reserves and the primary environmental analysis or report must be filed with the appropriate governmental authority. In addition, the terms "mineral resource", "measured mineral resource", "indicated mineral resource" and "inferred mineral resource" are defined in NI 43-101 and recognized by Canadian securities laws but are not defined terms under SEC Guide 7 or recognized under U.S. securities laws. U.S. investors are cautioned not to assume that any part or all of mineral deposits in these categories will ever be upgraded to mineral reserves. "Inferred mineral resources" have a great amount of uncertainty as to their existence, and great uncertainty as to their economic and legal feasibility. It cannot be assumed that all or any part of an "inferred mineral resource" will ever by upgraded to a higher category. Under Canadian securities laws, estimates of "inferred mineral resources" may not form the basis of feasibility or pre-feasibility studies, except in rare cases. U.S. investors are cautioned not to assume that all or any part of an inferred mineral resource exists or is economically or legally mineable. Accordingly, these mineral reserve and mineral resource estimates and related information may not be comparable to similar information made public by U.S. companies subject to the reporting and disclosure requirements under the United States federal laws and the rules and regulations thereunder, including SEC Guide 7.

Non-IFRS Financial Performance Measures
The Company has included certain non-IFRS measures in this news release. The Company believes that these measures, in addition to conventional measures prepared in accordance with IFRS, provide investors an improved ability to evaluate the underlying performance of the Company. The non-IFRS measures are intended to provide additional information and should not be considered in isolation or as a substitute for measures of performance prepared in accordance with IFRS. These measures do not have any standardized meaning prescribed under IFRS, and therefore may not be comparable to other issuers.

Total site costs, total site costs per ounce and various unit costs

Detour Gold reports total site costs and total site costs per ounce on a sold basis. Total site costs include production and operating costs such as mining, processing, site general and administration, bullion shipment, refining, agreements with Aboriginal communities, capital costs (including closure costs) and net of silver sales.

The Company calculates total site costs per ounce as the sum of total site costs (as described above) divided by the total gold ounces sold.

Detour Gold reports the following unit costs:

Mining unit costs: calculated as mining costs divided by total tonnes mined (ore + waste).
Processing unit costs: calculated as process costs (excluding bullion delivery and refining) divided by the total tonnes milled.
G&A unit costs: calculated as site G&A costs (excluding costs related to agreements with Aboriginal communities) divided by total tonnes milled.

Other companies may calculate this measure differently as a result of differences in underlying principles and policies applied.

Forward-Looking Information
This press release contains certain forward-looking information as defined in applicable securities laws (referred to herein as "forward-looking statements"). Forward-looking statements relate to future events or future performance and reflect current expectations or beliefs regarding future event. All statements other than statements of historical fact are forward-looking statements. Often, but not always, forward-looking statements can be identified by the use of words such as "plans", "expects", "is expected", "budget", "scheduled", "estimates", "continues", "forecasts", "projects", "predicts", "intends", "anticipates", "targets", or "believes", or variations of, or the negatives of, such words and phrases or state that certain actions, events or results "may", "could", "would", "should", "might" or "will" be taken, occur or be achieved.

Specifically, this press release contains forward-looking statements regarding the Technical Report being filed on SEDAR and posted on the Company's website on March 22, 2017; average annual gold production of approximately 656,000 ounces over the LOM; a mine life of approximately 23 years; LOM total site costs of US$758 per ounce sold; the annual mining rate increasing to 125 Mt with additional mine equipment; annual plant throughput of 23 Mt starting in 2021; average annual gold production below 550,000 ounces in 2019-2020; average annual gold production above 700,000 ounces in 2021-22; the economic assumptions and mine parameters contained in the LOM plan; the continued development of the Detour Lake pit with the start-up of the North pit in 2019 and West Detour pit in 2025; the processing of LG Fines contributing to achieving a plant throughput capacity of 23 Mt; the mining rate for the Detour Lake pit gradually ramping up from 100 Mt in 2017 to 125 Mt in 2022; during the period 2017-22, the strip ratio varying annually from 3.5:1 to 6.5:1; increasing the ultra-class haulage truck fleet from 32 CAT 795 trucks in 2017 to 38 in 2022; the West Detour pit ramping up to a maximum mining rate of 35 Mt per year; the Company's plans to use the West Detour pit, once depleted, for waste stockpiles and/or tailings disposition; the development of the North pit using a contractor; supplementing the plant feed with LG fines and/or lower grade material until the permit is received; using the North pit, once depleted, as a mine water pond during the operations; the Company continuing to stockpile material grading between 0.40 to 0.50 g/t Au in order to process the LG Fines; the processing of LG Fines commencing in 2019 at a rate of 0.5 Mt, increasing to 2.3 Mt in 2020 and consistently at 1 Mt per year in 2021+; a gradual ramp-up of the processing plant capacity, from 21.5 Mt in 2017 to 23 Mt in 2021+ (60,000 tpd from run-of-mine and 3,000 tpd from the LG Fines); an increase in the strip ratio over the next five years; the two year average metrics of the mine production plan; a 10% increase in mining costs over the LOM; a 4% increase in milling costs over the LOM; approximately 75% of operating costs being Canadian dollar denominated; sustaining capital costs over the LOM of $2.5 billion; estimated operating and capital costs; a $100/oz gold price change impacting the after-tax NPV5% by approximately $800 million; a $0.20/t mining unit cost change impacting the after-tax NPV5% by approximately $200 million; and the Company hosting an analyst workshop on March 23, 2017.

Forward-looking statements involve known and unknown risks, uncertainties and other factors which are beyond Detour Gold's ability to predict or control and may cause Detour Gold's actual results, performance or achievements to be materially different from any of its future results, performance or achievements expressed or implied by forward-looking statements. These risks, uncertainties and other factors include, but are not limited to, the ability of the Company to refinance its convertible notes and credit facility on or before maturity (November 30, 2017 and August 31, 2017, respectively), gold price volatility, changes in debt and equity markets, a reduction in the company's available cash resources, the uncertainties involved in interpreting geological data, risks relating to variations in recovered grades and mining dilution, variations in rates of recovery, changes or delays in mining development and exploration plans, the success of mining, development and exploration plans, changes in project parameters, changes in the company's relationship with its aboriginal partners and other stakeholders, risks related to the receipt of regulatory approvals, increases in costs, environmental compliance and changes in environmental legislation and regulation, interest rate and exchange rate fluctuations, general economic conditions and other risks involved in the gold exploration and development industry, as well as those risk factors discussed in the section entitled "Description of Business - Risk Factors" in Detour Gold's 2015 AIF and in the continuous disclosure documents filed by Detour Gold on and available on SEDAR at www.sedar.com.

Such forward-looking statements are also based on a number of assumptions which may prove to be incorrect, including, but not limited to, assumptions about the following: the availability of financing for exploration and development activities; operating and capital costs; the Company's ability to attract and retain skilled staff; the mine development schedule and related costs; the mine production schedule; the success and timing of the Company's mining and development plans, dilution control, sensitivity to metal prices and other sensitivities; the supply and demand for, and the level and volatility of the price of, gold; required regulatory approvals and the timing of the receipt of regulatory and governmental approvals for development projects and other operations; the timing and results of consultations with the Company's Aboriginal partners, the supply and availability of consumables and services; the exchange rates of the Canadian dollar to the U.S. dollar; energy and fuel costs; required capital investments; estimates of net present value and internal rate of returns, the accuracy of reserve and resource estimates, production estimates and capital and operating cost estimates and the assumptions on which such estimates are based; market competition; ongoing relations with employees and impacted communities and general business and economic conditions. Accordingly, readers should not place undue reliance on forward-looking statements. The forward-looking statements contained herein are made as of the date hereof, or such other date or dates specified in such statements. Detour Gold undertakes no obligation to update publicly or otherwise revise any forward-looking statements contained herein whether as a result of new information or future events or otherwise, except as may be required by law. If the Company does update one or more forward-looking statements, no inference should be drawn that it will make additional updates with respect to those or other forward-looking statements.

Contact

Paul Martin
President and CEO
(416) 304.0800
Laurie Gaborit
VP Investor Relations
(416) 304.0581