お知らせ • Apr 08
Arrow Minerals Limited Announces High Recoveries in First Metallurgical Results At Niagara
Arrow Minerals Limited announced high recoveries in first metallurgical results at Niagara. Niagara Bauxite Project and Bauxite Background: The Niagara Project is located approximately 70km North East of the city of Mamou, and approximately 330km North East of Conakry, the capital city of Guinea. The country's main national highway, N1 passes approximately 20km South West of the project. Arrow Minerals Ltd. commenced fieldwork in October 2024, and completed a drill program of 184 holes over 3 plateaux (Boussoura North, Boussoura North West, and the main Boussoura plateau) targeting high grade mineralisation intercepted in historical drilling. In the course of the exploration program, the main Boussoura plateau was subdivided into three (3) separate working areas, (Central, South, and Far-South). The Company has previously reported results from all 184 drill holes. Of these drill holes, 173 were used to inform the maiden Mineral Resource estimation, which was reported to the ASX on 25 March 20252. Eleven of these holes were used to assess regional prospectivity on a fourth plateau, Boussoura South West as the drill fleet demobilised via the South West quadrant of the permit. Arrow's 2024 drill program successfully achieved in its objective of completing drilling to inform the estimation of Mineral Resources, which will support the Company's 2025 scoping study. The Mineral Resource, effective 24 March 2024 is reported as 185Mt at 42.3% Al2O3, 2.7% SiO2, including higher grade subsets of 138Mt at 44% Al2O3, 2.8% SiO2,further inclusive of 48Mt at 48.2% Al2O3, 2.6% SiO2. As a part of the technical work supporting the Mineral Resource Estimate and the Company's scoping study, a series of twelve (12) samples were selected for analysis, comprised of nine (9) high priority plateau composites, and three (3) lower priority individual drillhole composites. Samples were submitted for analysis to assess the quantities of available alumina that may be recovered using the Bayer process; globally the most common industrial method of refining bauxite to produce alumina. This announcement presents the results of the Bayer digestion tests for the nine (9) high priority plateau composite samples for both low and high digestion temperatures. The three (3) drillhole composites will be reported as available. The information will be used to provide indicative pricing for Niagara bauxites in the Company's scoping study which is well progressed and due for completion in June 2025. Objective: The objective of the characterisation program is to support Arrow's scoping study, in terms of determining likely quality characteristics which influences the bauxite selling price. The characterisation program was also completed with the intent of incorporating results into ongoing feasibility studies, subject to a favourable outcome for the scoping study. Sample Selection: Sample selection was conducted by the Company's independent consultants SRK Consulting (UK) Ltd. (SRK) during the final stages of Mineral Resource Estimation following receipt of the finalised drilling database inclusive of geochemical analyses. The intent of the sample selection process was to produce a series of nine (9) composites that reflected high, medium, and low grade bauxites that adequately characterised the plateaux covered by the Mineral Resource, and to be included in the scoping study. Composite donor samples were selected from master pulps from geochemical samples from the auger program to provide the desired wide representivity of plateau coverage, geological, and geochemical range. An additional three (3) samples from individual boreholes were selected for analysis. Sample selection considered the following: Geology and Representivity: Different types of bauxite were observed from drillhole logging and evident in associated geochemical analysis. The various plateaux that have been drilled by Arrow, and previously Vale, exhibit subtly different characteristics of bauxite type, and/or grade. Locations The majority of samples were selected from the North, Central, and North West plateau areas. A resource grade composite was also selected from the Boussoura West plateau, in the expectation that the Company may complete additional drilling with the intent of estimating additional mineral resources at this location. The Company notes that there has been insufficient exploration to estimate a Mineral Resource at the Western plateau, and that it is uncertain if further exploration will result in the estimation of a Mineral Resource at this location. Grade Distribution: Representative variability of Al2O3, SiO2, Fe2O3 and Loss on Ignition at 1000C (LOI) were sought to ensure adequate sampling of the grade range of the mineral resource for these key variables. Target grades for the respective composite samples were determined using statistical analysis of the drilling database, with quartile ranges used to guide target grade ranges. Comparison with composite grades as assayed following compositing show that the target grades were achieved to within 1% discrepancy which is within cited accuracy limits of the analytical method used and is considered to show complete sample homogenisation. High Grade Composites: The high grade composites performed strongly under both low and high temperature Bayer digestion and suggest excellent processability. Low temperature digestion at 148°C achieved an average available alumina grade of 38.2% Al2O3 representing 81% of the average feed grade of 47.4% Al2O3. Reactive silica recovery averages 61%, based on a low SiO2 feed grade of 1.7% with just 1.0% dissolved under low temperature digestion. High temperature digestion at 245°C increased available alumina grade to 44.0% (93% recovery of feed), while reactive silica rose only marginally to 1.5% SiO2. This modest silica increase, coupled with a 5.8% gain in alumina yield, also highlights the amenability of the bauxite to high temperature Bayer processing with minimal silica-related penalties. The results reflect the high gibbsite content and low clay-bound silica, both favourable characteristics of the high grade bauxite for efficient and cost-effective refining.