Picnic Creek

Prospect, Probably inactive

Alternative names

Picnic

Commodities and mineralogy

Main commodities Ag; Au; Cu; Pb; Zn
Other commodities Ba
Ore minerals arsenopyrite; bornite; chalcopyrite; enargite; galena; sphalerite
Gangue minerals barite; chlorite; ferroan calcite; ferroan dolomite; quartz

Geographic location

Quadrangle map, 1:250,000-scale SP
Quadrangle map, 1:63,360-scale A-5
Latitude 67.086
Longitude -155.018
Nearby scientific data Find additional scientific data near this location
Location and accuracy This prospect is located 8.2 miles south of Akurekvik Pass, SW 1/4 and 0.3 mile southwest from the center of section 31, T. 20 N., R.18 E., of the Kateel River Meridian. Picnic Creek is approximately 1 kilometer north of the Sun deposit (SP039) at an elevation of approximately 3,400 feet. This location is accurate to within 500 feet.

Geologic setting

Geologic description

The Picnic Creek deposit was part of the general Sun site (SP039) until the 2012 update, however, drilling shows Picnic Creek to be discontinuous at depth from Sun (W.T. Ellis, Vice Pres., Alaska Earth Sciences, oral communication, 2014).
At the Picnic Creek prospect, located in the headwaters of Picnic Creek, approximately 1 kilometer north of the northern part of the drilled Sun Deposit (SP039), altered and iron stained gossanous rocks outcrop in a roughly 50 meter by 100 meter area. There is extensive talus covering. Ferrocrete gossan are currently forming from natural ground water springs, indicating weathering sulfides may be present under the talus cover (Gustin and Ronning, 2013).
The geology of Picnic Creek is characterized by a low-angle, extensional Picnic Creek fault with spoon-shaped geometry that terminates a belt of northeast-trending felsic metavolcanic and metasedimentary rocks generally dipping 30 degrees to 45 degrees southeast. The volcanic rock package is up to 1.5 kilometers thick and is both overlain and underlain by quartz-chlorite-mica schist. Known massive-sulfide mineralization is limited to the upper portion of the felsic volcanic rocks, extending about 2.4 kilometers along strike from the Picnic Creek saddle to west of drill hole Sun-14. Almost all of the mineralization lies beneath glacial cover, with exposures at only three locations (Marrs,1978).
Four horizons of sulfide mineralization have been recognized at the Picnic Creek prospect area. Grab samples of oxidized rocks have run up to 0.26 percent copper, 250 part per million (ppm) lead, 450 ppm zinc, 4.5 grams of silver per tonne, 0.42 grams of gold per tonne (Andover Mining Corp., 2012).
Geologic map unit (, )
Mineral deposit model Kuroko massive sulfide (Cox and Singer, 1986; model 28a)
Mineral deposit model number 28a
Age of mineralization Devonian, based on age of host rock (Gustin and Ronning, 2013).
Alteration of deposit Chloritic (Gustin and Ronning, 2013).

Production and reserves

Workings or exploration
Bear Creek discovered the Picnic Creek massive-sulfide prospect, located in the northern part of the current Sun project, in 1966 and drilled five holes at the prospect from 1975 to 1983. This drilling encountered copper, lead, zinc, and silver mineralization. Exploration as consisted of field mapping, sampling of rock and soil, and diamond core drilling as part of the exploration efforts conducted at Sun. The majority of the work was completed during the mid-1970s through early 1980s (Gustin and Ronning, 2013).
Four horizons of sulfide mineralization have been recognized at the Picnic Creek prospect area. Grab samples of oxidized rocks have run up to 0.26 percent copper, 250 part per million (ppm) lead, 450 ppm zinc, 4.5 grams of silver per tonne, 0.42 grams of gold per tonne (Andover Mining Corp., 2012).
Indication of production None
Reserve estimates None, a 2013 resource estimate was made for nearby Sun (SP039) (Gustin and Ronning, 2013).
Production notes None.

Additional comments

Exploration and discovery of volcanogenic massive-sulfide deposits and carbonate-hosted copper deposits were initiated by Bear Creek Mining Company ('Bear Creek'), the exploration arm of Kennecott Copper Corporation ('Kennecott'), in 1956, although the Ambler district had prior exploration and limited production of placer gold since the 1890s, production of copper in the early 1900s, and exploration for gold, uranium, and copper in the late 1940s. By 1966, Bear Creek had located geochemical anomalies at all of the major prospects now recognized in the Ambler district. Sunshine Mining Company ('Sunshine') entered the district in 1973, followed by Noranda Exploration Company ('Noranda'), as operator for a consortium that included GCO Minerals Company and Houston Oil & Minerals), the Anaconda Company ('Anaconda'), the Ambler Mining Company (a partnership of Sunshine and Anaconda), Cominco American Resources Inc. ('Cominco'), Falconbridge, and Union Carbide. By 1986, only Kennecott and Cominco remained active in the district. As recently as 2007, Teck Resources Limited, who acquired Cominco in 2001, still held property in the Ambler district, as did NovaGold Resources Inc., the regional native corporation for northwest Alaska, and Andover Mining Corp. No production has occurred in the Ambler district since the early 1900s (Gustin and Ronning, 2013).

References

References

Gustin, M.M., and Ronning, Peter, 2013, Technical Report on the Sun Project, Brooks Range, Alaska, 136 p.: (posted on www.sedar.com, Oct. 3, 2013) http://www.sedar.com/GetFile.do?lang=EN&docClass=24&issuerNo=00019735&fileName=/csfsprod/data147/filings/02118405/00000001/C%3A%5CSEDAR%5CFILINGS%5CAOX%5CAOXSunTechnicalReport.pdf (as of December 4, 2014).
Marrs, C.D., 1978, Geology of the Sun massive sulfide deposit, Ambler district, Alaska [abs.]: Northwest Mining Association, 84th Annual Convention, Spokane, Washington, Nov. 29-Dec. 2, 1978.
Reporters A. Angel and V.C. Zinno (Alaska Earth Sciences, Inc.)
Last report date 12/4/2014