Compiling historic YCGC data for lower Hunker Creek and reconstructing gold distribution Sydney van Loon
Yukon Consolidated Gold Corp. inventoried creeks for over four decades; operated up to 12 dredges YGS has obtained digital versions of 905 maps and 230 textual documents Valuable placer exploration tool for the industry Two additional study areas have been completed: mid-dominion in 2015 Sulphur Creek and lower Dominion in 2016
Yukon Consolidated Gold Corp. Currently digitizing the data we have and will continue to update a web map to easily access database
Application of data Compile surficial material thickness Reconstruct gold distribution Define dredge limits Determine exploration targets
Dataset issues Raw data (interpretation, accuracy, available) Digitizing data Location/georeference Accuracy and reliability of data depends on the scale of the project Gold distribution compilation for a drainage, the degree of accuracy has less emphasis; compared to a resource estimate
Hunker Creek Discover claim staked in 1897 24 km long drainage has undergone extensive prospecting, drilling, dredging, cat mining and modern mining activities since its discovery 5 dredges were active in the drainage, although not all at one time (1908 1966)
Geomorphology of Hunker Creek big broad braided rivers before glaciation temp much warmer Figure modified from Lowey (2004; Figure 24)
Geomorphology of Hunker Creek paleo-rock Creek deposition of White Channel gravel temp cooled prior to last ice age Figure modified from Lowey (2004; Figure 24)
Geomorphology of Hunker Creek outwash Figure modified from Lowey (2004; Figure 24)
Geomorphology of Hunker Creek Figure modified from Lowey (2004; Figure 24)
Hunker Creek placer settings valley width 5 M yrs ago modern valley width 100 m
Hunker Creek placer settings high-level bench tributary/gulch intermediate-level terrace modern creek
Hunker Creek drainage 12000 10000 8000 Hunker Creek drainage production 2007 to 8,355 oz. 24 operations were actively sluicing in the drainage and its tributaries 6000 4000 2000 0 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 Gold Production (oz.) Average
Study area 15 km from mouth of Colorado Creek downstream to Bear Creek in the Klondike River valley - 32 historic maps used to compile data - 12 active operations in study area Total of 1005 drillholes and shafts Total of 3.8 km 2 of dredge limits
Study area
Study area - drilling
Study area - dredging
Dredge history
Historic maps of study area
Dataset QA/QC
Dataset QA/QC 33 600!?!
Dataset QA/QC Removed anomalies: 1. Rabbit Gulch drill hole (1.6 ounces per cubic yard; $2,276 dollars per cubic yard) 2. Surficial material thickness greater than 100 ft in valley bottom Assigned trace gold recovery to the numeric value of 0.1 cents per cubic yard Used the historic gold price of $20.67; modern gold price $1400.00 per fine ounce
Drillhole statistics (modern grade) Highest grade recovered was $331 per cubic yard 14% drill holes has no assigned value Drill hole value (dollars per cubic yard) % Trace ($0.1 - $0.9) 10 1-10 44 10-20 14 20-30 6 30-50 7 51-331 5
Study area 150 m buffer 150 m
Valley bottom results
Surficial material overburden gravel
Overburden - Maximum thickness in valley bottom is 17 m Thickest on right limit on valley margin and tributary fans Thin overburden in Klondike River valley
Dredge section (gravel) - Maximum thickness in valley bottom is 30 m - Thickness increases in the Klondike River valley - Consistant thickness between Hester Creek and Dago Gulch (maximum 8 m)
Modern grade Rabbit Gulch $218 yd 3 Colorado Creek $322 yd 3 Dago Gulch $331 yd 3
Modern grade
Modern grade
Modern grade 86% of drillholes between $0-10 yd 3 $65, $55 and $50
Grade re-calculations Grades are calculated based on a total gravel zone thickness because the ground was evaluated for a dredging operation More realistic view would be to re-calculate the grade based on the theory that the pay zone is 6 ft (1.8 m) thick for the drainage Pull out additional patterns at the mouth of Hunker Creek and in the Klondike River valley
Grade recalculations
Klondike River valley Average modern grade of $4/yd 3 Grades were recalculated to account for a dilution factor
Klondike River valley 30% of drillholes $20/yd3 or greater
High-level bench results Paradise Hill 47 drill holes Dago Hill 36 drill holes
High-level bench area
Total section thickness
Grade (re-calculated for dilution)
Grade (re-calculated for dilution)
Pay channel
McConnell (1908)
Pay channel
Pay channel
Pay channel
McConnell (1908)
Exploration 17 m 2 m
Exploration
Exploration? preserved beneath overburden on left limit perched on the flank of Australian Hill reworked
Exploration Tatra Ventures Ltd. Klondike River valley - pay zone tight to bedrock and enriched gravel-bedrock interface - different gold source
Placer knowledge
References Green, L., 1977. The Gold Hustlers. Alaska Northwest Publishing Company, Anchorage, AK, 339 p. Lowey, G.W., 2004. Placer geology of the Stewart River (115N&O) and part of the Dawson (116B&C) map areas, west-central Yukon, Canada., Bulletin 14, 275 p. McConnell, R.G., 1905. Report on Klondike gold fields. In: Annual Report for 1901, Vol. XIV, Part B, Geological Survey of Canada, Publication No. 884, p. 1-71. Yukon Consolidated Gold Corporation maps. Energy, Mines and Resources Property File Collection; Archives Canada file numbere011079584, E011079590, E011156326, E011156323, C16, E011156383, E011156409, E011079606, E011156155, E011156151, E011156163, E011156335, E011157600, E011156394, E011156336, E011156337, E011156124, E007913810, E011156271, E007913637, E011156045, E011156387, E007913863, E011156225, E011156227, E007913857, E011156047, E011079536, E011079537, E011079582, and E011079583 Historic photos can be found on the Yukon Archives image database website: http://www.tc.gov.yk.ca/archives_imagesdatabase.html
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