お知らせ • Oct 10
Lara Exploration Ltd. Reports Maiden Copper-Gold Resource for the Planalto Project, Brazil
Lara Exploration Ltd. (Lara) reported the initial resource estimate of the 100% owned Planalto Copper-Gold Project in the Carajás Mineral Province of northern Brazil. GE21 Consultoria Mineral Ltda. (GE21), an independent mining and geological consulting company, estimated the Mineral Resources for the Planalto project as summarized in Table 1. Indicated Resources are estimated to be 47.7 million tonnes (Mt) at an average grade of 0.53% copper (Cu) and 0.06 grams per tonne (g/t) gold (Au), or 0.56% copper-equivalent (CuEq), containing 253 thousand tonnes (0.56 billion pounds) Cu or 267 thousand tonnes (0.59 billion pounds) CuEq. Inferred Resources are estimated to be 154 Mt at an average grade of 0.36%Cu and 0.04g/t Au, or 0.38%CuEq, containing 549 thousand tonnes (1.2 billion pounds) Cu or 585 thousand tonnes (1.3 billion pounds) CuEq. The Planalto Copper Project is located between Vale's Sossego copper mine and Cristalino copper deposit, and BHP's Pedra Branca copper mine and Antas mill, in the Carajás Mineral Province of northern Brazil. The Mineral Resources contain a shallow dipping higher grade Main Mineralization domain, surrounded by a lower grade Host Rock Mineralization domain, constrained within an open pit shell representing a reasonable prospect of eventual economic extraction (RPEE). The Resource Estimate: The Planalto resource is reported as a higher-grade Main Mineralization domain containing 47.7Mt of Indicated Resources at an average grade of 0.53% Cu and 77.7Mt of Inferred resource with an average grade of 0.51% Cu. The lower grade Host Rock domain mineralization that surrounds the Main Mineralization is reported as containing 76.3Mt of Inferred resources at an average grade of 0.2 % Cu. The Planalto copper gold deposit has many of the characteristics similar to other IOCG deposits in the Carajás. Mineralisation is interpreted to occur in stacked sub-parallel sheet-like structures that can be modelled fairly continuously over the 1,500m north-south strike length. Individual zones vary from a few meters to up to several tens of meters thick, and where there is an amalgamation of zones the mineralization can be as much as 100m in thickness. Chalcopyrite is the only copper-bearing mineral recognized in the deposit. Pyrite is rarely seen in the drill core in the south of the deposit (Homestead sector). In the north (Cupuzeiro sector above a northing coordinate value of 9295400N), pyrite can locally constitute up to 5% of the rock and is very abundant in the drill core intervals with more than 1% Cu. The geological model for the Planalto mineralization was created from 81 diamond drill holes totaling 25,337m. East-west oriented cross-sections were used to define continuity of the mineralization within and between sections, while taking account of structure, alteration and lithology. A 0.3% copper grade shell for modelling purposes was identified as providing a good level of continuity of mineralization. Several discrete mineralization domains were modelled, which have a south to north orientation, dipping to the east at 18-40 degrees. In the southeast of the Planalto deposit, the Silica Cap Target mineralization has been modelled as a separate domain with strike of 340 (NNE) and a 40° east dip. Mineralization modelled within the 0.3% Cu grade shells is characterized as the Main Mineralization domain, whereas the mineralization adjacent to and between the 0.3% Cu grade shells is characterized as the Host Rock Mineralization domain. Resource estimation parameters are summarized below: Assay and geological data available on or before July 03, 2024. were included in this resource estimate. Sample preparation and analytical procedures are described in the Company's previous news releases on the project and in the Technical Report. Industry-standard levels of QAQC checks were performed on assay data, including validation by umpire laboratories. Samples were composited to 2m lengths.High grade copper samples above 4% Cu were restricted to ensure these samples were not used to estimate model cells in which the centre of the cell was more than 35m from the sample. GE21 classified 3 different density zones in the geological model; the Oxide, the northern Cupuzeiro sector and the southern Homestead sector. The Cupuzeiro sector is characterized as mineralization with a more elevated occurrence of pyrite compared to the southern Homestead sector. For Domains with sufficient density measurements, the Domain density was calculated using the mean density of the samples within that domain after treating for outliers. Average values of density were applied for each domain individually. Domains with a low number of density measurements were assigned the overall average density of the Cupuzeiro, Homestead, or Oxide domains. The average densities of the Cupuzeiro, Homestead and Oxide domains are 2.87, 2.85 and 1.66g/cm3, estimated from the average of 144, 749 and 66 measurements,respectively.Ordinary Kriging ("OK") was used for the grade estimation for the Main Mineralization and Host Rock Mineralization domains for copper and gold. Inverse distance weighting (IDW) and Nearest Neighbour interpolation (NN) were used for verification of the OK estimates for copper and gold. The Mineral Resource classification by GE21was based on the assessment of a number of factors, including, sampling procedure, analysis, the sample grid spacing, the survey methodology, and the quality of assay data The classification of Indicated Mineral Resources was based on the first and second search step of Ordinary Kriging, which utilizes the variogram range in the search ellipsoid of up to: 105m x 60m x 20m in the Main Mineralization domain only. The Inferred Mineral Resource classification is all remaining estimated blocks in the Main Mineralization domain. The Host Rock Mineralization domain zone was classified as Inferred Resource class, irrespective of the search step used, due to the lower confidence in mineralization continuity. Mineral Resources of the Main Mineralization and the Host Rock Mineralization domains are reported inside a Reasonable Prospect of Eventual Economic Extraction (RPEEE) pit optimization shell and above a cut-off of 0.16% Copper Equivalent (CuEq), with simplified formula (CuEq% = Cu% + (Au g/t x 0.578).