Exploration

Detour Gold’s strategy is to create additional shareholder value through organic growth. The Company controls a strategic land position of over 1,000 km2 on the northernmost Abitibi Greenstone belts which offer an attractive potential for new discoveries.


Detour Lake Property, Ontario

Zone 58N

Zone 58N Highlights
  • High-grade gold underground target
  • Drilled ~135,000 metres to date
  • Indicated resource of 534,300 oz and Inferred resource of 136,100 oz
  • Proceeding with a cost evaluation for an advanced underground exploration program

Detour Gold continues to evaluate a number of targets on its large prospective Detour Lake property (647 km²). Exploration work continues in the Lower Detour area where the Company has encountered high grade gold intersections at Zone 58N. This major east-west structural break is located approximately 6 kilometres south of the Detour Lake mine.

The Company has completed approximately 135,000 metres of drilling to define Zone 58N with part of the drilling at a closer spacing to better define the tonnage and grade estimation due to the high nuggety and coarse nature of the gold.

The gold mineralization within Zone 58N is hosted in a swarm of tonalitic dykes that intrude mafic volcanic rocks and are spatially controlled by the margin of a large intermediate intrusion. Gold mineralization is found in quartz-tourmaline-carbonate veins containing less than 5% sulphides. The east-west mineralized system extends along a strike length of 450 metres, from surface to a depth of 800 metres. It remains open for expansion at depth.

In July 2018, the Company released an initial independent mineral resource estimate for the Zone 58N gold deposit. The resource estimate for incorporates the assay results from 332 diamond drill holes totaling 109,700 metres. Drill spacing is approximately 25 x 25 metres in the upper 500 metres of the deposit and 40 x 40 metres below 500 metres. The mineral resource model only considers mineralized zones that are potentially mineable by underground extraction and contained within the modelled wireframes. The block model was prepared and constrained using 3D wireframes of geological domains that are associated with gold mineralization. Grade estimation was interpolated into blocks using a combination of Inverse Distance Cubed (ID3) and Nearest Neighbor (NN). The mineral resource was reported using a gold cut-off grade of 2.2 g/t and a minimum true thickness of 3 metres.

Metallurgical testing performed on a total of 31 composites has confirmed that Zone 58N mineralization is amendable for processing through the existing Detour Lake processing plant. All composites were tested for grinding, gravity separation and cyanide leaching of both gravity products (concentrate and tails). Based on these initial tests, gold recovery is estimated at 97.5% for the stated mineral resource grade.

The Company is proceeding with a cost evaluation for an advanced underground exploration program. This program would include site access and surface infrastructure, and underground development (i.e. access to mineralized zones and platform for further exploration drilling). Subject to a positive evaluation, the Company would determine the appropriate timeline for the program.

Mineral Resources Tonnes
(millions)
Grade
(g/t Au)
Contained
Gold Ounces
Zone 58N Indicated    2.87 5.80 534,300
Inferred    0.97 4.35 136,100

Notes:

  1. Reported in accordance with the Canadian Institute of Mining, Metallurgy and Petroleum (“CIM”) standards for mineral resources and reserves, adopted by CIM Council, as amended.
  2. All HQ and NQ core assays obtained by analytical methods described in the March 2017 Technical Report under Section 11.3.3. Quality Assurance and quality control procedures included the systematic insertion of blanks, standards, and duplicates into the sample stream.
  3. Mineral resources reported at a cut-off grade of 2.2 g/t Au, using a gold price of US$1,300 per ounce and a US$/C$ exchange rate of 1.25 with an assumed mining dilution of 12%.
  4. Mineralized domains were modeled using selections of mineralized intervals based on varying degrees of visual alteration (sulphide, sericite, and quartz veining) due to good correlation with the gold mineralization. Based on the nuggetty nature of the gold mineralization and limited strike length continuity, a grade-based approach to establish domains was not used.
  5. Mineral resource encompasses 10 domains, each defined by its individual 3D wireframe with a minimum true thickness of 3.0 metres. Domains are subvertical, strike east-west, with the two largest domains plunging 85 degrees to the east.
  6. High grade gold assays were capped at values ranging from 20 to 120 g/t Au depending on the domain.
  7. Bulk density value of 2.7 t/m³.
  8. Interpolation completed using 2 metre composites. The block grade estimate used 1-pass nearest neighbor (NN) and 4-pass Inverse Distance Cubed (ID3) interpolation method.
  9. Block model uses block sizes of 5 x 3 x 5 metres.
  10. Mineral resources are not mineral reserves as they do not have demonstrated economic viability.
  11. Numbers may not total due to rounding.

Detour Lake Cross-section

Zone 58N – Cross-section

Detour Lake Level Plan

Zone 58N – Level Plan


Zone 58N Additional Targets

All assays have been received for the targets drilled proximal to Zone 58N during the first half of 2018. From the 18 holes completed totaling 5,621 metres, many drill holes encountered alteration and mineralization similar to Zone 58N, including visible gold. The best gold intercepts from this program include:

  • 77.8 g/t over 1.5 metres (DLD-18-422)
  • 2.70 g/t over 10.0 metres (DLD-18-428)
  • 2.74 g/t over 8.6 metres and 2.31 g/t over 11.0 metres (DLD-18-432)
  • 2.08 g/t over 5.7 metres (DLD-18-418)

Approximately 5,500 metres of drilling is planned west and northwest of Zone 58N in the second half of 2018.


Burntbush Property, Ontario

Burntbush Property Highlights
  • Located on a major deformation zone, west of Hecla’s Casa Berardi gold mine
  • Geology similar to Lower Detour area on Detour Lake property
  • Airborne geophysical survey completed in 2017
Burntbush Property-Geology Map

The Company controls two groups of contiguous claims totaling 494 km2 comprising the Burntbush property, approximately 70 km south of its flagship Detour Lake mine.

The Burntbush East and West properties are strategically located along the Casa Berardi deformation zone in the Abitibi Greenstone Belt, approximately 35 and 75 kilometres respectively, west of the Casa Berardi gold mine operated by Hecla Mining Company, which has produced approximately 1.9 million ounces of gold since it commenced production in 1988.

In general, exploration on the Ontario side of the Casa Berardi fault has been minimal due to limited access, overburden and the lack of outcrop exposures. Historical and more recent exploration activities have focused on the main structural break. The Burntbush grassroot properties cover more than 80 kilometres of primary (EW) and secondary (NE-SW) subsidiary faults. It also encompasses a number of gold anomalies intersected in old diamond drill holes, including an intercept of 6.41 g/t over 2.9 metres drilled by Newmont in 1985, and in till samples from a 2005 regional program by the Ontario Geological Survey. Immediately east of the West claim group, drilling by Lakeshore Gold in the mid-2000s delineated a 500 metres gold mineralized horizon (Porphyry Creek Zone). Within the East claim group, in the portion not controlled by Detour Gold, a small NI 43-101 compliant gold resource (A8 3200 Vein System) was reported in 2013 by Alpha Minerals.

A geological mapping program and ground geophysical surveys are starting on the Burntbush property in the third quarter of 2018. The Company is planning a 2,000 metre diamond drilling program following the results of the ground geophysical surveys.