.
Enter the email you signed up with and we'll email it to you.
Location: 20 km N from Crooked Creek, Alaska, United States
725 E. Fireweed Ln., Suite 200AnchorageAlaska, United States99503
Stay on top of the latest gold discoveries. Examine the latest updates on drilling outcomes spanning various commodities.
Mining scale, mining and mill throughput capaciites.Full profiles of select mines and projects.
Shaft depth, mining scale, backfill type and mill throughput data.Full profiles of select mines and projects.
Equipment type, model, size and quantity.Full profiles of select mines and projects.
Camp size, mine location and contacts.Full profiles of select mines and projects.
Donlin Gold LLC is owned 60% by Novagold Resources Inc. and 40% by Donlin Gold Holdings, 100% wholly-owned by Paulson Advisers LLC and its affiliates.
- subscription is required.
The Donlin deposits include eleven mineralized areas that exhibit slightly different geological settings but generally fall into two geologically similar deposit areas: ACMA and Lewis. ACMA, or the intrusive sill and shale–siltstone sedimentary setting, includes the Aurora, 400, Akivik, ACMA, and East ACMA mineralized zones. Lewis, or the massive greywacke-hosted intrusive dike setting, includes the South Lewis, Lewis, Vortex, Rochelieu, Queen, and North Akivik mineralized zones.Veins in north–northeast-striking, east- or west-dipping faults and fracture zones are the primary control on gold distribution and are ubiquitous in all mineralized areas. Northwest- and northeast-striking veins occur locally but are relatively rare. Veins are narrow (typically < 1 cm wide), highly irregular, discontinuous, and generally sparsely distributed, although vein density can locally range up to two to eight per meter in higher-grade zones. Vein zones vary from 2 to 35 m wide and 100 to 350 m long. Individual vein zones generally display limited lateral and vertical continuity; however, swarms of many anastomosing vein zones form larger mineralized corridors characterized by extensive lateral and depth continuity.Vein corridors are more apparent in the north–northeast-trending dikes of Lewis than in the west–northwest-trending ACMA sill zone. The greater width of the sill-hosted ACMA mineralized zone makes discreet corridors less obvious (but still present). Mineralized zones follow steeply dipping dikes and sills beyond the depth limits of current drilling, or over a vertical range of at least 945 m.Veins are best developed in relatively more brittle intrusive rocks and massive greywacke. Small, irregular, carbonate-altered mafic bodies often host very high-grade gold as sulfide dissemination, replacement, and breccia fill. Structural breccias in sedimentary rocks are also favorable sites for high-grade gold. Gold distribution in the deposit closely mimics the intrusive rocks. The more steeply dipping sills in the ACMA sill sequence host the highest-grade and most continuous igneous-hosted mineralized zones, particularly where intersected by northeast-striking “feeder” dikes and faults. Gold grade is directly proportional to vein density and intensity of overlapping disseminated sulfide vein aureoles. The dike-dominant Lewis deposit areas consist of sheeted veins with limited disseminated sulfide in the wall rocks and are characterized by lower-grade and less continuous mineralized zones.Mineralization Gold-bearing zones are coincident with quartz–carbonate–sulfide veins and related disseminated sulfide aureoles in hydrothermally altered rhyodacite bodies and, to a lesser extent, in sedimentary rock near igneous contacts. Continuity and grade of mineralized material within the rhyodacite host rocks varies directly with vein spacing and the amount of vein and disseminated arsenopyrite, the principal gold-bearing mineral. Gold in sedimentary rocks and minor mafic igneous bodies is generally limited to small and discontinuous vein and breccia fill occurrences.Vein and Disseminated Mineralization Veins in the ACMA–Lewis area are subtle in appearance and vary from < 1 mm to 20 cm wide, averaging < 1 cm. They formed in brittle fractures and are typical of open-spaced fillings with vugs, drusy quartz-lined cavities, vein wall-banded and cockscomb quartz, and bladed carbonate. Veins are composed of gray to clear quartz, white to tan carbonate, and as much as 3% sulfides.Mineralized zones are consistently oriented sub-parallel to the main d1 axis (024) of the compressive structural regime (Piekenbrock and Petsel, 2003). Veins in the ACMA–Lewis resource evolved through a continuum (V1 through V3) of changing mineralogy and increasing gold grade while maintaining a generally consistent north-northeast strike and southeast dip. The final carbonate–quartz vein set (V4) has a broader range of orientation.MacNeil (2009) found that the average vein orientation for all veins is 024/71 degrees. This orientation is generally consistent across all domains and vein types, which indicates that veins in the Donlin deposits formed during the same mineralizing event.A comparison by host rock shows that veins in igneous rocks strike more easterly and dip more steeply than veins in sedimentary rocks, probably due to refraction across lithologic contacts.Several quartz and carbonate phases have been recognized, including pre-gold-stage Mn– calcite veins and wall rock replacement and cockscomb quartz veins; Fe–dolomite in main gold stage veins; and post-gold-stage clear quartz veins and ankerite stringer veins.
Success!