Inferred Mineral Resource Estimate - Florida Mountain Deposit:
Sensitivity analysis of grade and tonnage at varying cut-off grades
|Cutoff||Tonnes||g Au/t||oz Au||g Ag/t||oz Ag||g AuEq/oz||Eq Au oz|
1.Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability.
2. Mineral Resources are comprised of all model blocks with gold-equivalent values greater than or equal to 0.30 g/t that lie within an optimized pit and below the as-mined surface.
3. Gold equivalent = g Au/t + (g Ag/t ÷ 85)
4. Rounding may result in apparent discrepancies between tonnes, grade, and contained metal content.
5. The estimate of mineral resources may be materially affected by geology, environment, permitting, legal, title, taxation, sociopolitical, marketing or other relevant issues.
6. The effective date of the mineral resource estimate is January 30, 2018.
7. E. Max Baker, P. Geo, of Reno, Nevada, is a Qualified Person within the meaning of NI 43-101 - Standards of Disclosure for Mineral Projects. Mr. Baker has reviewed and verfied the scientific and technical information contained herin.
Florida Mountain Geology
The Florida Mountain Project is a low-sulphidation gold-silver epithermal system similar to that of the DeLamar Gold and Silver Project. The important exception between DeLamar and Florida Mountain is that the Late Cretaceous Silver City granite crops out on the flanks of Florida Mountain and was extensively penetrated by workings of historic underground mines. Field relations demonstrate the lower basalt flows partially buried an erosional, paleo-topographic high of Silver City granite. Surface exposures and maps of the underground workings, as well as early drilling at Florida Mountain, led Lindberg (1985) to infer the granite forms a northeast-trending ridge beneath a relatively thin capping of quartz latite, tuff breccia, and one or more flows of rhyolite. Similar to the DeLamar area, both fissure veins and the bulk-mineable type of mineralization are present at Florida Mountain and have contributed to past gold and silver production.1
Florida Mountain Metallurgy
The NERCO Mineral Company conducted extensive column-leach and agitation-leach tests on samples of mineralized drill core from the Sullivan, Stone Cabin, and Clarke areas of Florida Mountain in the 1980s (Statter, 1989). The results of the column-leach tests, which were run for approximately 60 days, are summarized in the table below.
NERCO Florida Mountain Column-Leach Tests (from Statter, 1989)1
Integra plans on conducting further metallurgical test work on Florida Mountain mineralization in the future.
As indicated in the table above, gold and silver recoveries in these tests ranged from 52% to 95% for gold, and 32% to 54% for silver on crush fractions ranging from 0.25 to 2 inches, indicating potential amenability of Florida Mountain mineralization to future low cost heap-leaching methods.
1. NI 43-101 Technical Report and Estimated Gold – Silver Resources, DeLamar Project, Integra Resources Corp. Effective Date October 1, 2017.