- Wide spaced drilling has defined stratiform zinc and lead mineralisation over 20km of strike within carbonate sediments of the lower sedimentary units of the Earaheedy Basin (Proterozoic) in Western Australia
- Historical drilling intercepted high-grade zinc up to 18.6% within an intersection 3.3m @ 11.2% Zn, and 0.93% Pb from 150m. Other drill-holes include 2m @ 8.23% Zn and 2.77% Pb from 103m
- Coarse grain sphalerite (Zn) and galena (Pb) with pyrite and marcasite occurs as breccias, veins and replacement zones within carbonates
- The mineralisation style is similar to Mississippi Valley Type (MVT) large high grade base metal deposits that include the Devonian Lennard Shelf deposits of the Kimberley Region of Western Australia
- Rumble plans to commission a detailed gravity survey to compliment the magnetics with the aim to delineate basement structures and directly define high density sulphides to drill test
The Earaheedy Zinc project is located approximately 110km north of Wiluna, Western Australia, covering most of the known zones of primary carbonate hosted zinc–lead mineralisation in the Earaheedy Basin. Broad spaced drilling (completed in the 1990’s) defined several prospects containing oxidised and primary Zn-Pb mineralisation (zinc dominant) associated a flat lying to shallow northeast dipping laterally continuous dolomite horizon with over 20 kilometres strike. The initial drill spacing was 5 to 10km. The current drill spacing is approximately 1km by 1km.
Three prospects were defined within the current Earaheedy Project.
At ‘Navajoh’, an intersection of 7.3 metres @ 6.1 % Zn, 0.77% Pb (including 3.3 metres @ 11.2% Zn, and 0.93% Pb) remains untested for 500 metres to 1 kilometre in all directions.
At ‘Magazine’ there are no follow up holes within a 1kilometre radius of a discovery intersection of 11 metres @ 3.5% (Zn + Pb) which includes 2 metres @ 8.2% Zn, 2.8% Pb).
At ‘Chinook’ intersections include 6 metres @ 3.63% (Zn + Pb).
Review of the historic drilling has concluded that approximately half the drill holes did not intercept the target horizon. A total of 64 drill holes were completed within the project area (E69/3464) with only 35 drill holes intercepting the stratiform zinc horizon (including partial end of hole intercepts). Structural contouring of the flat lying mineralised carbonate horizon has highlighted the extent of mineralisation. Using Zn%-m (cumulative assay values > 0.15% Zn per hole) contouring as a guide (Figure 1), significant areas of untested potential mineralisation remain completely open. North of the Magazine prospect, drill hole spacing is up to 2km. Note that the Zn%-m contouring represents metal endowment per drill hole and does indicate economic grade and widths.
The Earaheedy Project, based on the mineralisation style, host rocks, known basement structural architecture and the current drilling density (2km by 1km and 1km by 1km spacing), has the potential to host a significant Zn – Pb
resource. The target size is similar to the Pillara (Blendevale) Zn – Pb deposit located in the Devonian limestones of the Lennard Shelf, Kimberley Region, Western Australia which produced 10.3 Mt @ 6.9% Zn and 2.3% Pb. Of note, the discovery drill-hole (8m @ 8.9% Zn, 3.5% Pb below 210m) at Pillara, was the 136th drill hole in the area.
Figure 1. Earaheedy Zinc Structural Contours (Zn%-m) Drill Holes Intercepting Mineralised Horizon
Rumble Resources Limited Transaction
Option agreement executed with Rumble Resources Limited (RTR) over the Earaheedy Zinc project, as announced to the ASX by RTR on the 12th October 2017. Zenith will receive RTR shares worth $50,000 as an initial option payment. RTR may purchase a 75% interest in the Earaheedy Zinc project for $550k in shares within 2 years, subject to a 2 year extension (for a further payment of $200k cash / shares at ZNC’s election). Upon exercise of option to purchase the Earaheedy Zinc project by RTR, ZNC is then free carried at 25% to the end of a BFS.
EARAHEEDY MANGANESE PROJECT – WA (Zenith 100%)
The Proterozoic aged Earaheedy Basin north of Wiluna in Western Australia is a potential new manganese province with similarities to the giant Kalahari manganese field in South Africa. As first mover Zenith established a strong land position with tenements. Zenith’s priority target is high-grade (>40% Mn) manganese oxide formed by weathering or supergene upgrade of primary mineralisation.
Zenith completed the first ever drilling for manganese in the western Earaheedy in late 2010 at the Lockeridge prospect, intersecting a shallow dipping bed of primary manganese carbonate mineralisation. Better results from Lockeridge include: 12m @ 11.1% Mn from 28m depth, and 3m @ 18.0% Mn from 37m depth.
Primary manganiferous carbonate at Lockeridge is supergene enriched near surface. Previous Zenith drilling completed in 2010 was stepped out more than 250 metres down dip from the outcrop, and intersected primary manganiferous carbonate with Mn grades in the range 3 to 10% Mn for up to 1.2 km down dip. The 2013 program established potential for supergene manganese oxide with both holes intersecting mineralisation. Hole ZTAC026 (3m @ 25.1% Mn incl. 1m @ 29.6%) intersected the target around 100 metres down dip from the high grade outcrop, and hole ZTAC025 (3m @ 20.2% Mn) hit partially oxidised mineralisation around 150m down dip from surface outcrop.
The first DSO grade Mn drill intersections recorded in the Earaheedy Basin were reported by Zenith in 2012 at the Red Lake prospect. Drilling results include; 3m @ 41% Mn (within 5m @ 34.8% Mn from 22m depth), and 3 metres @ 34.8% Mn from 19 metres, including 1m @ 42.3% Mn. Subsequent drill programs defined continuous near surface high-grade manganese at Red Lake. Based on a revised geological interpretation (ASX Release 9thSeptember 2014) the Red Lake resource is: 1.4Mt @ 19.0% Mn at a 10% Mn cut-off grade with a higher grade component of 0.2Mt @ 30.0% Mn at a 25% Mn cut-off grade as presented in the Table below. The resource is classified under the JORC Code 2012 as Inferred, based on confidence in, and continuity of, the results from the drilling campaigns, and surface mapping.
On the 15th April 2015 Zenith reported an Inferred Mineral Resource (JORC 12) for the near surface oxide portion of the Lockeridge manganese prospect. The maiden estimate is: 2.6Mt @ 20.6% Mn at a 10%Mn cut-off grade as presented in the Table below. The resource is classified under the JORC Code 2012 as Inferred, based on confidence in, and continuity of, the results from the drilling campaigns, and surface mapping.
Note: The Mineral Resource was estimated within constraining wireframe solids based on the specified nominal lower cut-off grade for Mn. The Mineral Resource is quoted from all blocks above the specified Mn cut-off grade %. Differences may occur due to rounding.