Final 2020 Drilling Results At Eureka Gold Project

COEUR D'ALENE, ID - Timberline Resources Corporation reported final results from the 2020 drilling program at its 100%-controlled Eureka Project in Nevada. It completed the program in December 2020 after a total of approximately 3,800 meters, comprised of 2,438m of reverse circulation (RC) and 1,365m of diamond core drilling. The three (3) core holes (BHSE-188C, -190C, and 191C) were significant step-outs to the east targeting the down dip expansion of the Lookout Mountain mineralization.

After careful logging and three-dimensional geological analysis, it is now apparent that the core holes were not drilled sufficiently deep to test the rock units that host the known high-grade (= 3 g/t) gold in the Lookout Deposit. The drilling did not encounter significant gold mineralization (>0.3 g/t), but the drill core does exhibit abundant alteration and thick intercepts of anomalous Carlin-Type gold, plus low-level silver-lead-zinc mineralization.

Key Results: Confirmed the presence of additional normal faulting through the Graben Zone that may host opportunities for high-grade gold along trend and at depth; Intercepted significant pyrite that is consistent with a halo above and around the IP chargeability anomaly previously reported; Intercepted highly anomalous gold (up to 0.223 g/t) and silver (up to 86 g/t) in several intervals; and Gathered mounting evidence that Lookout Mountain is a close analogue to the multi-million-ounce Archimedes - Ruby Hill1,2 Mine, located 12 km to the north, including: Brecciated limestone, carbonaceous and pyritic breccias, dolomitized carbonates, silicification, and altered felsic intrusive rocks; plus Lead (up to 0.34%), zinc (up to 0.57%), and silver mineralization with anomalous gold and a proximal association with Carlin-Type gold mineralization.

Patrick Highsmith, President and CEO, said, "Along with our recently reported geophysical anomalies, these step-out exploration core holes at our Lookout Mountain target provide important evidence that there are large overlapping mineral systems at depth. We are also now aware of more faults cutting through the favorable Carlin-Type host stratigraphy. The interaction of these faults with the right host rocks are excellent targets for high-grade gold such as that we drilled in the main resource area and in the Water Well Zone in 2020. Work is well underway to present numerous attractive drill targets for 2021 at the Lookout Target and other analogous settings."

The three core holes passed through similar geology. The thickness of younger volcanics in the area varied from approximately 35m to 175m. Beneath the volcanics, the drilling encountered limestones that began as well-bedded and oxidized but included increasing shale interbeds at depth. Fracturing and veining also increased with depth, often indicating the presence of faulting. Drill holes BHSE-188C and -190C included significant intervals of black sulfide-matrix breccia and oxidized dolomites before bottoming in fine-grained silicified and pyritic intrusive dikes of variable thickness. Drill hole BHSE-191C was lost in highly fractured rock before reaching its target depth.

The anomalous gold was associated primarily with decalcified limestones and with black matrix breccias. The subtle silver-lead-zinc mineralization is most often associated with veining in dolomite, jasperoid breccias, and silicified and stockwork-veined fine-grained dikes. This style of silver-lead-zinc mineralization may indicate the presence of a carbonate-replacement-deposit (CRD) nearby. The Eureka District is known for CRDs that were deposited much earlier in time than the Carlin-Type gold mineralization.

Using the surface geological mapping, drill logs, and biostratigraphic information from fossils, the Timberline team has prepared a new geological cross section through the Lookout Mountain Area. The cross section shows that the Dunderberg Shale and other host rocks from the Lookout Resource are down-dropped by east-dipping normal faults cutting through the target area. It is now apparent that this core drilling was not sufficiently deep to test the rocks that host the Lookout mineralization.

The IP geophysics reported in February also indicates that the heart of the chargeability anomaly is below the depth of drilling in the Graben Zone. However, there are lobes of high chargeability that rise closer to the surface, both north and south of the 2020 drilling. These shallower IP anomalies will be among the near-term drill targets at Lookout and in the Graben Zone.

The construction of the cross section has also shown that many other favorable targets exist where Carlin-Type host rocks are cut by abundant faults within the Lookout Trend. The team is currently preparing a work program for 2021 that will target potential settings for high-grade Carlin-Type gold mineralization in the Lookout, South Lookout, and Rocky Canyon areas. Additional three-dimensional geologic work is underway to demonstrate the best target analogies to the high-grade setting at Lookout Mountain.