Saddle Prospect, Fairbanks Mining District, Fairbanks North Star Borough, Alaska, USAi

Regional Level Types
Saddle Prospect	Prospect
Fairbanks Mining District	Mining District
Fairbanks North Star Borough	Borough
Alaska	State
USA	Country

Location: The saddle prospect is located on the divide between Wolf Creek and Fairbanks Creek; NW1/4 sec. 28, T. 3 N., R. 2 E., of the Fairbanks Meridian.
Geology: Prior to 1969, the divide between Fairbanks and Wolf Creeks was host to several producing mines and numerous prospects. The mineralization sought in all of these mines and prospects was high grade gold mineralization hosted by large northwest and northeast trending shear zones. Low grade mineralization was known to be present at the McCarty (ARDF no. LG152), Pioneer (ARDF no. LG155) and Pennsylvania (ARDF no. LG156) mines, along the margins of higher grade portions of the shear zones. However, these lower grade zones could not be profitably worked using the existing technology (W. McCarty, oral commun., 1988). In 1969, International Minerals and Chemicals (IMC) began an exploration program designed to address the possibility of surface mining the lower grade material in this area. IMC conducted trenching and rotary drilling targeted at low grade, zones adjacent to previously mined high grade shear zones. These activities resulted in discovery of the Saddle prospect (Pilkington, 1970). IMC's initial exploration efforts on the Saddle prospect consisted of geological mapping and sampling of four, previously excavated trenches and open cuts. IMC also excavated 5 new dozer trenches totalling 4,299 feet. Initial sampling was conducted in three trenches previously excavated by Keystone Mines Inc. One of these trenches was located in the footwall of the Pennsylvania shear zone, approximately 1,300 feet northeast of the Pioneer shaft . This trench exposed a schist-hosted quartz-bearing shear zone oriented N 35 E, 65 NW. One-foot channel samples collected in the hanging wall of this shear included 9 feet that assayed 0.9 ppm gold (0.029 ounces of gold per ton) and 58.3 ppm silver (1.70 ounces of silver per ton). The rocks consisted of iron-, arsenic- and antimony-oxide-stained silver-gray schist. IMC also sampled two dozer trenches previously excavated by Keystone Mines approximately 500 feet west of the Pioneer shaft. These two dozer trenches cut the Pioneer shear zone which trends N 70 W and dips 50 S. The first trench had 17 feet that assayed 0.54 ppm gold (0.016 ounces of gold per ton) and 75.6 ppm silver (2.20 ounces of silver per ton); the rocks in the trench consisted of brecciated and silicified quartz-mica schist containing minor iron- and antimony-oxide staining. The second trench had 25 feet that assayed 5.68 ppm gold (0.166 ounces of gold per ton) and 142.6 ppm silver (4.16 ounces of silver per ton) in silicified and brecciated quartz-mica schist with weak iron-oxide staining. In order to test the down-dip extent of suspected northeast-trending mineralization picked up in trenches on the Saddle prospect, IMC conducted rotary drilling using a 5-inch rotary drilling rig (Pilkington, 1970). Two vertical rotary holes totalling 485 feet were drilled on the Saddle prospect. Based on the results from trenching and drilling, IMC calculated drill inferred reserves of 2,111,000 tons grading 0.037 ounces of gold per ton and 0.46 ounces of silver per ton in the Saddle Zone (Pilkington, 1970). These reserves were considered subeconomic at then-current gold and silver prices and IMC terminated its lease with Keystone Mines Inc. in 1970.
Workings: In 1969 International Minerals and Chemicals (IMC) began an exploration program designed to address the possibility of surface mining the lower grade material in this area. IMC conducted trenching and rotary drilling targeted at low-grade zones adjacent to previously mined high-grade shear zones. These activities resulted in discovery of the Saddle prospect (Pilkington, 1970). IMC's initial exploration efforts on the Saddle prospect consisted of geological mapping and sampling of four previously excavated trenches and open cuts. IMC also excavated five new dozer trenches totalling 4,299 feet. Initial sampling was conducted in three trenches previously excavated by Keystone Mines Inc. IMC also sampled two dozer trenches previously excavated by Keystone Mines approximately 500 feet west of the Pioneer shaft. IMC conducted rotary drilling using a 5-inch rotary drilling rig (Pilkington, 1970). Two vertical rotary holes totalling 485 feet were drilled on the Saddle prospect. In 1987, Keystone Mines leased their holdings to Fairbanks Exploration Inc. and in 1988 BP Minerals, acting as operator of a joint venture with Fairbanks Exploration Inc. conducted drilling designed to confirm and expand on the results previously generated by IMC. BP Minerals drilled 3,465 feet of reverse circulation drilling in 7 holes Klessig (1988).
Reserves: Based on the results from trenching and drilling, IMC calculated drill inferred reserves of 2,111,000 tons grading 0.037 ounces of gold per ton and 0.46 ounces of silver per ton in the Saddle Zone (Pilkington, 1970). These reserves were considered subeconomic at then-current gold and silver prices and IMC terminated its lease with Keystone Mines Inc. in 1970.

Commodities (Major) - Au; (Minor) - Ag, Sb
Development Status: None
Deposit Model: Gold-quartz veins.

Other Databases

Link to USGS - Alaska:	LG151

Other Regions, Features and Areas containing this locality

References