Occurrence Details


Occurrence Number:
115O 178
Occurrence Name:
Big Alex
Occurrence Type:
Hard-rock
Status:
Anomaly
Date printed:
4/29/2025 3:11:53 AM

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General Information
Capsule
Work History
Assessment Reports
References

General Information

Secondary Commodities: antimony, gold, molybdenum
Deposit Type(s): Orogenic Au, Vein Au-Quartz
Location(s): 63°1'23.06" N - -138°36'3.86" W
NTS Mapsheet(s): 115O02
Location Comments: Location marks highest recordedgold-in-soil geochemical result.
Hand Samples Available: No
Last Reviewed:

Capsule

WORK HISTORY
 
Staked as Rum Run cl 1-20 (YC17658) in Sep/99 by G.G. Richards who collected reconnaissance rock and soil samples while staking the claims.
 
In Jun/2000 Richards staked Rum Run cl 21-40 (YC17677) to the south and cl 41-50 (YC20212) and cl 53-59 (YC20222) 2 km to the southeast.  During the 2000 field season Richards carried out geological mapping, contour soil sampling and limited rock chip sampling on all of the Rum Run claims.
 
Richards carried out addition geological mapping, soil and rock sampling programs in 2001, 2003 and 2005 and limited ground magnetics and VLF geophysical programs in 2003 and 2005.
 
In Oct 2007 Richards staked Cigar cl 1-12 (YC63021) north of Rum Run claims 1-20.  In Aug/2009 Richards carried out contour soil sampling over parts of the Cigar and Rum Run claim blocks.
 
In Sep/2009 Pacific Ridge Exploration Ltd optioned a package of 203 mineral claims commonly referred to as the Mariposa Gold property from G.G. Richards for cash, claims and certain work commitments. The Mariposa Gold property includes the Rum Run and Cab claims and the area surrounding this occurrence.
 
In the fall of 2009 Pacific Ridge carried out reconnaissance scale soil sampling over the entire block of optioned claims to verify Richards previous results.
 
In 2010 as part of a larger property wide exploration program Pacific Ridge prospected, rock sampled and grid soil sampled the area covering Rum Run claims 3-19. In Aug/2010 the company staked Cab cl 1-30 (YD07758) west of Rum Run claims.
 
In the spring of 2011 Pacific Ridge flew an airborne magnetometer survey over the occurrence area. Although Pacific Ridge Exploration carried out a large exploration program in 2011 including drill testing numerous anomalies, the area surrounding this occurrence (the Big Alex gold-in-soil anomaly) only received limited work.
 
In Apr/2012 Pacific Ridge Exploration announced its 2012 exploration program which included infill soil geochemistry, ground geophysical surveys and prospecting of the Big Alex gold-in-soil anomaly (this occurrence.
 
GEOLOGY
 
The area is located approximately 120 km south of the town of Dawson City, along the southern half of the Scroggie Creek drainage in west-central Yukon. The occurrence lies near the southern boundary of NTS map sheet 115N&O which was recently remapped by S. Gordey and J. Ryan (2004 and 2005) of the Geological Survey of Canada.  Ryan and Gordey and others have recently finished remapping NTS map sheet 115J & K (the map sheet lying immediately south of the occurrence) and are in the final stages of releasing their results (tentatively 2012).
 
The occurrence area covers Rum Run claims 1-40 which lie on the west side of Scroggie Creek. The area is believed to be underlain by a Devonian to Mississippian age sequence of quartz mica schist, amphibolite, orthogneiss and other metavolcanic rocks. The northern half of the Rum Run claims (claims 1-20 – this occurrence) are intruded by a large Early Jurassic granitic batholith described by Gordey and Ryan of the Geological Survey of Canada as a composite intrusive complex comprised of many phases which exhibit diffuse contacts with the country rocks. A poorly defined body of pegmatite occurs in the Camp Creek – (occurrence) area within the batholith.
 
Exploration results for Rum Run claims 21-40 are covered by Minfile Occurrence #115O 177.
 
G.G. Richards the owner of the Rum Run and other claims,  placer mined along Scroggie Creek during the 1980’s. Richards staked his claims to try and located the source of placer gold occurring in the Scroggie Creek drainage. Richards spent the 1990’s systematically exploring and sampling Rum Run claims 1-20. Geological mapping outlined a body of pegmatite underlying the occurrence area which Richards named the Pegmatite Zone. Gold mineralization is associated with pegmatite dykes located within this zone. The best result obtained by Richards (3020 ppb gold) was obtained from very fine grained sulfide layers occurring in quartz breccias phases of pegmatite dykes cutting foliated medium-grained hornblende granodiorite.  Soil sampling returned numerous spot anomalies while geophysics outlined the general trend of various fault zones.
 
Following  Pacific Ridge Exploration’s execution of an option agreement with G. G. Richards, the company carried out a late season ridge and spur deep auger soil sampling program to verify Richards’ earlier results. The program’s results generally confirmed Richards’ results.  
 
Pacific Ridge’s 2010 ground exploration program was focused on the Scroggie and Mariposa Creek areas.  Grid soil sampling outlined five main gold in-soil anomalies; Skookum Jim, Hackly, Gertie, Maisy May and Big Alex (this occurrence). The Big Alex gold-in-soil anomaly measures approximately 1 km long by 0.5 km wide and trends north-south parallel to Scroggie Creek. Based on limited information the anomaly consists of two zones of anomalous gold in soils centred at the north and south ends of the anomaly. Limited geological mapping and prospecting  show that the zones are underlain by pegmatite dykes. Gold-in-soil values range to 203 ppb gold with elevated values of antimony and molybdenum. Chip sampling southeast of the southern anomaly returned 3.0 g/t gold from pyritic quartz breccia within pegmatite dykes and granite bedrock exposed by placer mining. Placer miners working in the vicinity of the anomaly have recovered gold in quartz nuggets.
 
The 2011 airborne geophysical survey shows that the Big Alex soil anomaly overlies  a magnetic low flanked on either side by north-south trending magnetic highs which likely represent structural faults which may provide ground preparations that are favourable for the migration of gold-bearing fluids and the deposition of gold. The faults are part of  property wide network of structures which collectively make up the Mariposa fault.
 
G.G. Richards and Pacific Ridge Exploration theorized that the gold associated with the Big Alex anomaly was likely associated with the pegmatite dykes  underlying the area and thus limited in extent. Therefore the company elected to concentrate their efforts on more promising areas of the Mariposa Gold property with the intent of returning to the anomaly as time and money allowed.
 
REFERENCES
 
GORDEY, S.P. AND RYAN, J.J. 2005.  Geology, Stewart River Area (115N, 115 O and part of 115J), Yukon Territory; Geological Survey of Canada, Open File 4970, scale 1:250 000.
 
PACIFIC RIDGE EXPLORATION LTD, Feb/2011.  Assessment Report  #095527 by J. Fingler.
 
PACIFIC RIDGE EXPLORATION LTD, News Release. 23 Sep/2009, 7 Dec/2009, 20 Apr/2010, 17 Aug/2010, 2 Mar/2011, 13 Apr/2011, 11 Apr/2012.
 
PACIFIC RIDGE EXPLORATION LTD, Apr/2011.  Web Site: www.pacificridgeexploration.com.
 
RICHARDS, G.G. May/2001.  Assessment Report #094228 by G.G. Richards.
 
RICHARDS, G.G. Nov/2001.  Assessment Report #094250 by G.G. Richards.
 
RICHARDS, G.G. May/2004.  Assessment Report #094481 by G.G. Richards.
 
RICHARDS, G.G. Dec/2005.  Assessment Report #094679 by G.G. Richards.
 
RICHARDS, G.G. Feb/2010.  Assessment Report #095249 by G.G. Richards.
 
RICHARDS, G.G. AND PACIFIC RIDGE EXPLORATION LTD. Dec/2010.  Assessment Report #095337 by G. Norman.
 
RYAN, J.J. AND GORDEY, S.P. 2002.  Bedrock geology of Yukon-Tanana terrane in southern Stewart River map area, Yukon Territory. Geological Survey of Canada, Current Research 2002-A1, 11 p.
 
RYAN, J.J. ET AL., 2003.  Update on bedrock geological mapping of the Yukon-Tanana terrane, southern Stewart River map area, Yukon Territory. Geological Survey of Canada. Current Research 2003-A9, 7 p.
 
Ryan, J.J. AND GORDEY, S.P., 2004;  Geology Stewart River Area (Parts of 115N/1,2,7,8 and 115O/2- 12), Yukon Territory; Geological Survey of Canada, Open file 4641, scale 1:100 000.
 
YUKON EXPLORATION AND GEOLOGY OVERVIEW 2010, p. 29, 60; 2011, p. 46-45, 65, 72.

Work History

Date Work Type Comment
8/30/2009 Geochemistry Contour soil sampling carried out before Pacific Ridge Exploration optioned claims. Pacific Ridge carried reconnaissance soil sampling after optioning property to verify G.G. Richards earlier results.
4/30/2011 Airborne Geophysics Airborne magnetic survey flown over Rum Run claims.
12/31/2010 Geochemistry Chip sampled on Rum Run claims.
12/31/2010 Geochemistry Grid soil sampled Rum Run claims.
12/31/2010 Other Carried out prospecting across Rum Run claims.
12/31/2005 Geology Geological mapping carried out in 2001, 2003 and 2005
12/31/2005 Geochemistry Additional soil sampling carried out in 2001, 2003 and 2005.
12/31/2005 Ground Geophysics Ground magnetic and VLF survey carried out in 2003 and 2005.
12/31/2000 Geochemistry Limited rocock chip sampling carried out on all Rum Run claims.
12/31/2000 Geology Carried out on all Rum Run claims.
12/31/2000 Geochemistry Contour sampling, carried out on all Rum Run claims.
12/31/1999 Geochemistry Reconnaissance scale.
12/31/1999 Geochemistry Reconnaissance scale.

Assessment Reports that overlap occurrence

Report Number Year Title Worktypes Holes Drilled Meters Drilled
097277 2017 Technical Report on the Mariposa Project in the White Gold District, Yukon Territory All Weather Road - Development, Surface, Rock - Geochemistry, Mechanical - Trenching
096551 2012 2011-2012 Soil Geochemical, Trenching and Diamond Drilling Assessment Report Diamond - Drilling, Diamond - Drilling, Drill Core - Geochemistry, Drill Core - Geochemistry, Rock - Geochemistry, Rock - Geochemistry, Soil - Geochemistry, Soil - Geochemistry, Magnetics - Ground Geophysics, Magnetics - Ground Geophysics, Backhoe - Trenching, Backhoe - Trenching 28 5250
095949 2011 2011 Airborne Geophysical Survey Report on the Mariposa Property Magnetic - Airborne Geophysics, Magnetic - Airborne Geophysics, Magnetic - Airborne Geophysics
095527 2010 2010 Soil Geochemical Assessement Report on the MARIPOSA Property Soil - Geochemistry, Soil - Geochemistry, Soil - Geochemistry
095249 2009 Geochemical Report on the Mariposa Property Rock - Geochemistry, Silt - Geochemistry, Soil - Geochemistry, Prospecting - Other, Data Compilation - Pre-existing Data
095337 2009 Ridge and Spur Soil Geochemical Assessment Report on the Mariposa Property Soil - Geochemistry
094679 2005 Geophysical Report on the Rum Run Property Detailed Bedrock Mapping - Geology, EM - Ground Geophysics, Magnetics - Ground Geophysics
094481 2003 Geochemical Geological Report on the Rum Run Property Rock - Geochemistry, Soil - Geochemistry, Magnetics - Ground Geophysics
094250 2001 Geochemical Geological Report on the Rum Run Property Soil - Geochemistry, Detailed Bedrock Mapping - Geology, EM - Ground Geophysics, Line Cutting - Other, Prospecting - Other
094229 2000 Geochemical Geological Report on the Rum Run Property Rock - Geochemistry, Silt - Geochemistry, Soil - Geochemistry, Detailed Bedrock Mapping - Geology, Prospecting - Other
094228 2000 Geochemical Geological Report on the Rum Run Property Rock - Geochemistry, Silt - Geochemistry, Soil - Geochemistry, Detailed Bedrock Mapping - Geology
094227 2000 Geochemical Geological Report on the Rum Run Property Rock - Geochemistry, Silt - Geochemistry, Soil - Geochemistry, Detailed Bedrock Mapping - Geology

Related References

Number Title Page(s) Reference Type Document Type
2003-9(D) Yukon Digital Geology (version 2) Yukon Geological Survey Open File (Geological - Bedrock)