Occurrence Details

Occurrence Number:
116B 189
Occurrence Name:
Pacific Deposit
Occurrence Type:
Hard-rock
Status:
Past Producer
Date printed:
9/15/2024 10:43:52 PM

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General Information
Capsule
Work History

General Information

Primary Commodities: gold
Aliases: Brewery Creek
Deposit Type(s): Epithermal Au-Ag: Low Sulphidation, Porphyry-related Au
Location(s): N - W
NTS Mapsheet(s): 116B01
Location Comments: Location from satellite image and company map
Hand Samples Available: No
Last Reviewed:

Capsule

Cretaceous (91Ma) Tombstone Suite monzonite and quartz monzonite intrudes Paleozoic Earn and Road River Groups lithologies as a series of semi-conformable sills along a 15km strike length defining the Brewery Creek Reserve Trend.  Younger, Tombstone Suite syenite and biotite monzonite occur locally in the south-central portion of the property.  All compositional phases of the Tombstone Suite intrusives are known to host gold mineralization.

Sill emplacement is primarily controlled by a tectonized, graphitic argillite at the contact between the Earn and Road River Groups.  This contact is also the locus of NNE-directed thrust faulting that has placed thin (<150 m thick) sequences of Silurian siltstone against Devonian siliciclastic rocks.  The age of faulting is probably related to earlier Mesozoic compression along the Dawson, Tombstone and Robert Service Thrust Faults and the closing of the Selwyn Basin.

Brewery Creek deposits exhibit characteristics of both epithermal type and intrusive-related gold systems. It is generally considered to be an alkalic intrusion-associated gold deposit, as most of the mineralization is concentrated within or proximal to the monzonites of the Cretaceous Tombstone Suite.  Gold mineralization occurs in fracture-controlled quartz stockwork in both siliciclastic and intrusive rocks along an east-northeast striking, moderately south dipping structural trend known as the Brewery Creek Reserve Trend. 

Altered intrusive rocks are typically the preferred host for gold mineralization, however gold mineralization at the Pacific deposit exhibits a strong preference for a siltstone host, and in other deposits into adjacent intrusive rocks.  Major ore-controlling structures in intrusive rocks are related to a post Tombstone age, NNW compressional event that produced ESE and NE striking conjugate shears and ENE listric normal faulting localized along graphitic argillite/intrusive sill contacts. Approximately 85% of the mined ore was hosted by the various Cretaceous-aged quartz monzonite sills with the balance contained in silicified and brecciated Earn Group sediments.

The Pacific deposit was mined during the 1996-2002 mining phase. The deposit lies along the Brewery Creek Reserve Trend, immediately east of the Classic Fault. The remaining resource is defined by 17 core holes and 80 RC holes, totaling 6,966 m. The remaining resource measures approximately 500 m in length, 50 m wide, and 300 m down dip.

Pacific is the only zone in the district that is hosted primarily by Paleozoic siltstone.  Mineralization is generally tabular and follows a combination of shallow south dipping bedding and high-angle Brewery Creek Reserve Trend parallel faults. The resource has been segmented by several post-mineralization northwest-trending dextral faults.

Work History

Date Work Type Comment
6/1/1998 Geochemistry
6/1/1998 Lab Work/Physical Studies
6/1/1998 Drilling
6/1/1998 Trenching
6/1/1997 Geochemistry
6/1/1997 Geology
6/1/1997 Geochemistry
6/1/1997 Drilling
6/1/1997 Trenching
6/1/1996 Geochemistry
6/1/1996 Drilling
6/1/1996 Other
6/1/1996 Geochemistry
6/1/1996 Drilling
6/1/1996 Trenching
6/1/1996 Geochemistry
6/1/1996 Geochemistry
6/1/1996 Development, Surface
6/1/1994 Lab Work/Physical Studies
6/1/1994 Geochemistry
6/1/1994 Lab Work/Physical Studies
6/1/1994 Geochemistry
6/1/1994 Drilling
6/1/1994 Drilling
6/1/1994 Studies
6/1/1994 Trenching
6/1/1994 Geochemistry
6/1/1994 Geology
6/1/1993 Lab Work/Physical Studies
6/1/1993 Airphotography
6/1/1993 Studies
6/1/1993 Lab Work/Physical Studies
6/1/1993 Development, Surface
6/1/1993 Geochemistry
6/1/1993 Drilling
6/1/1993 Studies
6/1/1993 Lab Work/Physical Studies
6/1/1993 Geochemistry
6/1/1992 Geochemistry
6/1/1992 Studies
6/1/1992 Other
6/1/1992 Geochemistry
6/1/1992 Drilling
6/1/1992 Ground Geophysics
6/1/1992 Ground Geophysics
6/1/1992 Lab Work/Physical Studies
6/1/1992 Trenching
6/1/1992 Geochemistry
6/1/1991 Geochemistry
6/1/1991 Drilling
6/1/1991 Studies
6/1/1991 Other
6/1/1991 Lab Work/Physical Studies
6/1/1991 Drilling
6/1/1991 Ground Geophysics
6/1/1991 Trenching
6/1/1991 Geochemistry
6/1/1991 Geochemistry
6/1/1991 Geology
6/1/1991 Development, Surface
6/1/1990 Lab Work/Physical Studies
6/1/1990 Geochemistry
6/1/1990 Drilling
6/1/1990 Geochemistry
6/1/1990 Drilling
6/1/1990 Ground Geophysics
6/1/1990 Ground Geophysics
6/1/1990 Lab Work/Physical Studies
6/1/1990 Trenching
6/1/1990 Geochemistry
6/1/1990 Geochemistry
6/1/1990 Geology
6/1/1989 Geochemistry
6/1/1989 Drilling
6/1/1989 Geochemistry
6/1/1989 Drilling
6/1/1989 Ground Geophysics
6/1/1989 Ground Geophysics
6/1/1989 Pre-existing Data
6/1/1989 Trenching
6/1/1989 Geochemistry
6/1/1989 Geochemistry
6/1/1989 Geology
6/1/1988 Geochemistry
6/1/1988 Geology
6/1/1988 Geochemistry
6/1/1988 Geochemistry
6/1/1988 Other