This split is pulverized using a ring mill to 90% passing a 150-mesh screen. Nominal 250 gram splits were taken for each sample using a rifle splitter. At ALS, the samples were dried at a maximum temperature of 60 degrees Celsius and the entire sample was then crushed with a jaw crusher to 90% passing a ten-mesh screen. (ALS) and transported to their lab in Reno, Nevada. Drilled core samples were collected from the core shed by ALS Ltd. The QA/QC samples include blanks to test for contamination, high and low-grade lithium standards to test for accuracy and duplicates to test for precision. Randomly inserted in the sample stream were QA/QC samples, which represent 10.1% of the total assays. Each sample was assigned a unique identification number to ensure security and anonymity. For duplicate samples, one half of the core is cut in half again and the two halves are bagged and sampled separately to test sampling and assay precision.
The core was cut in half with diamond blade saws, using fresh water and half bagged for sampling. The geologist determined the length of the assay samples by lithology and averaged 1.60 m. The boxes of core were logged, photographed, cut and sampled by company employees and consultants. Sampling procedure and assaying methods were as follows: drilled core was brought from the field to the companys core shed located in Orovada, Nevada. Quality assurance and quality control: the data collection and analysis procedures employed to develop the information presented in this news release use industry-standard quality techniques and procedures. The pit optimization utilized the appropriate cost inputs and the lithium cut-off grade of 1,334 ppm to determine the economic resource pit shell for the final resource estimation from the block model. In accordance with CIM Definition Standards along with Mineral Resource and Mineral Reserve Estimation Best Practice Guidelines (2019) a resource economical pit shell has been derived from performing a pit optimization calculation using Vulcan Software. Only clay/ash ore material was estimated for lithium grade and each domain was estimated independently.
Lithium grades have been estimated throughout the block model using the composited assay database with the declustered weights through ordinary kriging (OK) modeling method. These faulted block zones were used to limit the lithium grade estimation to the blocks and drill holes existing within each representative faulted block zone. Fault traces were connected to generate seven faulted block zones. Lithium grades were interpolated for clay/ash lithologies in the block model through ordinary kriging modeling method from a 1 m composited quality database. This composited database used existing geocodes from the Torque database to isolate the compositing of grades to each correlated geologic lithology. A compositing run length of 1 m was chosen based upon mining assumptions of potential waste removal. A composited database was then created from this native ISIS database. A Vulcan ISIS database was designed and populated with native geologic data from Excel datasheets containing borehole assays, collars, lithological and survey data which were exported from the Companys Hexagon Mining Drillhole Manager (Torque) database. A regular block model with a block size of 25 m by 25 m by 1 m was generated. Mineral resource estimate methodology: a block model was created by mining contractor Sawtooth Mining, LLC using Mapteks Vulcan 3D subsurface geologic modeling software.
#Maptek vulcan drift analyser update#
provided a project update for the Thacker Pass lithium project in Humboldt County, Nevada including an increase in the Mineral Resource estimate to 13.7 million tonnes (Mt) of lithium carbonate equivalent (LCE) grading 2,231 parts per million lithium (ppm Li) of Measured and Indicated (M&I) and 4.4 Mt of LCE grading 2,112 ppm Li of Inferred Resources.