Compiling historic YCGC data for lower Hunker Creek and reconstructing gold distribution. Sydney van Loon Yukon Geological Survey

Transcription

1 Compiling historic YCGC data for lower Hunker Creek and reconstructing gold distribution Sydney van Loon

2 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

3 Yukon Consolidated Gold Corp. Currently digitizing the data we have and will continue to update a web map to easily access database

4 Application of data Compile surficial material thickness Reconstruct gold distribution Define dredge limits Determine exploration targets

5 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

6 Hunker Creek Discover claim staked in 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 ( )

7 Geomorphology of Hunker Creek big broad braided rivers before glaciation temp much warmer Figure modified from Lowey (2004; Figure 24)

8 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)

9 Geomorphology of Hunker Creek outwash Figure modified from Lowey (2004; Figure 24)

10 Geomorphology of Hunker Creek Figure modified from Lowey (2004; Figure 24)

11 Hunker Creek placer settings valley width 5 M yrs ago modern valley width 100 m

12 Hunker Creek placer settings high-level bench tributary/gulch intermediate-level terrace modern creek

13 Hunker Creek drainage Hunker Creek drainage production 2007 to 8,355 oz. 24 operations were actively sluicing in the drainage and its tributaries Gold Production (oz.) Average

14 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

15 Study area

16 Study area - drilling

17 Study area - dredging

18 Dredge history

19 Historic maps of study area

20 Dataset QA/QC

21 Dataset QA/QC !?!

22 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 $ per fine ounce

23 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)

24 Study area 150 m buffer 150 m

25 Valley bottom results

26 Surficial material overburden gravel

27 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

28 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)

29 Modern grade Rabbit Gulch $218 yd 3 Colorado Creek $322 yd 3 Dago Gulch $331 yd 3

30 Modern grade

31 Modern grade

32 Modern grade 86% of drillholes between $0-10 yd 3 $65, $55 and $50

33 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

34 Grade recalculations

35 Klondike River valley Average modern grade of $4/yd 3 Grades were recalculated to account for a dilution factor

36 Klondike River valley 30% of drillholes $20/yd3 or greater

37 High-level bench results Paradise Hill 47 drill holes Dago Hill 36 drill holes

38 High-level bench area

39 Total section thickness

40 Grade (re-calculated for dilution)

41 Grade (re-calculated for dilution)

42 Pay channel

43 McConnell (1908)

44 Pay channel

45 Pay channel

46 Pay channel

47 McConnell (1908)

48 Exploration 17 m 2 m

49 Exploration

50 Exploration? preserved beneath overburden on left limit perched on the flank of Australian Hill reworked

51 Exploration Tatra Ventures Ltd. Klondike River valley - pay zone tight to bedrock and enriched gravel-bedrock interface - different gold source

52 Placer knowledge

53 References Green, L., The Gold Hustlers. Alaska Northwest Publishing Company, Anchorage, AK, 339 p. Lowey, G.W., 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., Report on Klondike gold fields. In: Annual Report for 1901, Vol. XIV, Part B, Geological Survey of Canada, Publication No. 884, p Yukon Consolidated Gold Corporation maps. Energy, Mines and Resources Property File Collection; Archives Canada file numbere , E , E , E , C16, E , E , E , E , E , E , E , E , E , E , E , E , E , E , E , E , E , E , E , E , E , E , E , E , E , and E Historic photos can be found on the Yukon Archives image database website:

54 Questions/comments/suggestions