High Grade Li Mineralisation at South Basin
Sydney, Sep 5, 2016 AEST (ABN Newswire) - Global Geoscience Limited (
ASX:GSC) advises that it has completed its preliminary review of recently acquired historical exploration data over the southern basin ("South Basin") of the Company's Rhyolite Ridge Lithium-Boron Project in Nevada. The data demonstrates the significant tonnage together with the potential for higher-grade zones of mineralisation within South Basin.
Highlights:
- Review of historic drill hole data reveals high-grade mineralisation in the upper zone at South Basin. Plan and cross-sections attached.
- High-grade lithium intersections include:
-- 12m at 2660ppm Li (1.42% LCE) from 65m in SBH-6
-- 14m at 2566ppm Li (1.37% LCE) from 55m in SBH-7
-- 18m at 2580ppm Li (1.37% LCE) from 88m in SBH-15
-- 12m at 2588ppm Li (1.38% LCE) from 37m in SBHC-8
-- 26m at 2513ppm Li (1.38% LCE) from 91m in SBHC-19
- Maiden JORC-compliant Resource estimate at South Basin in progress, anticipated October 2016
- Field work focussed on identifying and testing high-grade mineralisation, drilling in Dec Qtr
- Exploration Target calculated for North Basin, trench/channel samples indicate similar lithium and boron grades to South Basin
- PFS to commence following completion of Resource estimate and preliminary metallurgy, fully funded
Global's Managing Director, Bernard Rowe commented: "The delineation of a higher grade zone with significant tonnage potential at South Basin is extremely pleasing and demonstrates the considerable potential of the Rhyolite Ridge project. The work completed to date demonstrates that Rhyolite Ridge is clearly a very large mineralised system with a very significant resource potential. Work currently underway is focussing on identifying and testing zones of higher grade mineralisation. Drill permitting is in progress and we expect to be drilling in the December quarter."
High-Grade Zone at South Basin
A review of the recently acquired exploration database confirms the existence of zones of high-grade lithium mineralisation (approximately 1.4% LCE). The higher grade zone occurs at or near the top of the upper horizon and, based on rock chip samples taken along the western margin of the basin, appears to extend to surface. The high-grade mineralisation has been intersected in most of the 36 holes drilled at South Basin. It is 10m to 20m thick and extends over an area of at least 2000m by 400-800m. The intersections have been calculated using a 2000ppm Li cut-off.
South Basin Li-B-K Mineralisation
The high-grade lithium mineralisation described above generally occurs in the upper part of a thick zone of lithium-boron-potassium mineralisation that averages about 40m in thickness. Selected intersections include (1200ppm Li lower cut-off):
- 46m at 1734ppm Li (0.92% LCE), 1.36% B and 1.04% K from 76m in SBH-5
- 44m at 1850ppm Li (0.98% LCE), 0.97% B and 0.78% K from 55m in SBH-7
- 33m at 1884ppm Li (1.00% LCE), 1.17% B and 0.85% K from 134m in SBH-13
- 40m at 1910ppm Li (1.02% LCE), 1.16% B and 0.89% K from 89m in SBHC-1
- 49m at 1934ppm Li (1.03% LCE), 1.00% B and 0.85% K from 99m in SBHC-3
South Basin Resource Estimation
The recently acquired exploration database includes 21 core and 15 RC holes completed by JOGMEC/American Lithium Minerals (2010-2011) at South Basin. The drill holes provide sufficient information to calculate an initial JORC-compliant Resource estimate. RungePincockMinarco has been engaged to undertake the Resource estimation. The Company anticipates completion of the maiden Resource estimation in October 2016. No additional drilling is required to complete the estimate.
Preliminary Feasibility Study
Upon completion of a Resource estimate and subject to positive preliminary metallurgical test work, Global anticipates being in a position to commence a pre-feasibility study (PFS) to assess the economic potential of the project. This work is fully funded from the recent capital raising.
Exploration Target - North Basin
The Company has estimated an Exploration Target for the North Basin of:
1 to 1.5 billion tonnes of 1000ppm to 2000ppm lithium, 0.5% to 1.0% boron and 0.5% to 1.0% potassium
The potential quantity and grade of the Exploration Target is conceptual in nature and there has been insufficient exploration to estimate a Mineral Resource. It is uncertain if further exploration will result in the estimation of a Mineral Resource.
The Exploration Target is based on results from surface geological mapping, rock chip and channel/trench sampling. The Exploration Target is not based on drill hole data. The previous work was completed by JOGMEC/American Lithium Minerals in 2010/2011 and Global has acquired the data. The same mineralised stratigraphy present at South Basin also occurs at North Basin. The mineralised rocks have been observed at surface over an area of approximately nine square kilometres (not continuous). A thickness of 50m to 70m for the mostly flat lying mineralisation has been assumed based on similarities with South Basin. The actual thickness of mineralisation at North Basin is unknown and will be tested with drilling.
Trench locations are shown in Figure 1 (see link below). Trenches are spaced at 200 to 400m over a strike length of 1.6km. Due to the shallow dip, trench samples only represent a limited part (thickness) of the mineralisation. Trench samples were collected from 3m-long continuous channels cut into the rock. When in the mineralisation, the trench samples contain 1000-2840ppm Li, 1000-14000ppm B and 0.5-1.3% K.
The level of previous exploration activity pre-2010 is not well known. US Borax explored and drilled in the area in the 1980's and, at the time, described it as the second largest boron deposit in USA. Lithium was noted as occurring with the boron. Results of the drilling are not known. JOGMEC and American Lithium Minerals explored the area for lithium in 2010/2011 and excavated nine trenches at North Basin, as described above.
The area hosts "clay-type" lithium deposits that formed in a shallow lake environment. Stratabound lithium and boron mineralisation is hosted in a Tertiary-aged sequence of carbonate-rich fine-grained sediments and minor volcanoclastic rocks. The basin is underlain by Tertiary volcanic rocks and Cambrian sediments. At South Basin, lithium and boron mineralisation occurs in at least two separate zones. The upper unit is 30 to 50m thick and hosts lithium grades of 1800-2000ppm and up to 1% boron. The lower unit is 20 to 60m thick with average lithium grades of 1400ppm. The Exploration Target will be tested with a program of wide-spaced drilling scheduled to be completed during the December quarter.
Future Work Programme
The recently obtained exploration database will expedite the calculation of a maiden JORC-compliant Mineral Resource estimation at South Basin and will provide valuable sample material for metallurgical and other test work.
The Company's current work program includes:
- Maiden JORC-compliant Resource estimate at South Basin (Oct 2016);
- Evaluation of the North Basin using historic and recently collected data;
- Drill program to test for zones of high-grade mineralisation at North and South Basins (Dec Qtr); and
- Preliminary metallurgical test work to define processing options and development of optimal processing routes (Dec Qtr).
About Rhyolite Ridge Lithium-Boron Project
The Rhyolite Ridge lithium-boron project is located close to existing infrastructure in southern Nevada. The project is located 15km from a sealed road and power and the nearby town of Tonapah is already supporting local mining/exploration projects. The project has potential as a long life, low cost source of lithium and boron. Two sedimentary basins (North and South) contain thick, shallow and flat-lying zones of mineralisation. The mineralisation is hosted by carbonate-rich, fine-grained sediments (marl) that were deposited in a shallow lake/basin. The two basins have a combined surface area of approximately 17 sq km. Global has the exclusive right to purchase 100% interest in the project from the owner, a private Nevada company.
To view tables and figures, please visit:
http://abnnewswire.net/lnk/4TJM2EH7
About Global Geoscience Limited
Global Geoscience Limited (ASX:GSC) is a Sydney-based mineral exploration company specialising in greenfield exploration and mineral discovery. The Company's main focus is for copper, gold and silver on its mostly 100%-owned projects in Nevada and Arizona in the United States, and Peru in South America.
| ||
|
