Breaker Resources NL (ASX: BRB) has announced more shallow, wide, high-grade drilling results from ongoing infill reverse circulation (RC) and diamond drilling at the 2.2km-long Bombora gold discovery within the 100%-owned Lake Roe Gold Project, 100km east of Kalgoorlie in WA.
The 40m x 20m spaced infill RC results continue to upgrade the open pit and underground mining potential of the Bombora discovery.
The drilling is part of an ongoing program targeting an initial JORC Resource in late 2017. A key objective of the recent drilling is to provide adequate drill resolution to identify the structural
controls of gold mineralisation within and along strike to the main 2.2km Bombora discovery zone.
The diamond drilling component of the drilling is focused mainly on structural orientation, validation and obtaining samples for preliminary metallurgical testwork.
Breaker’s Executive Chairman, Mr Tom Sanders, said the results are very encouraging:
“We have now drilled ~70,000m and the quality and size dimension of the results continue to be consistent with the early stages of a large, new greenfields gold camp in a premier mining jurisdiction,” Mr Sanders said.
“The higher drill density is starting to clarify the mineralisation controls. The results we are seeing upgrade the largely untested depth potential in the 2.2km-long Bombora gold discovery, as well as the gold potential over large areas along strike, where many significant gold drill intercepts are ‘floating in space’ due to the wide-spaced nature of earlier drilling.
We are starting to see stacked, plunging, sub-horizontal, high-grade quartz vein arrays sitting above controlling faults for example, and this bodes well for the long term underground mining potential.
We are also starting to see more west-dipping gold lodes with good continuity adjacent to (and locally within) the main 2.2km Bombora discovery that have not been adequately tested by the west-orientated reconnaissance drilling. This upgrades the potential of several large areas including the Crescent Prospect, the Bombora South Prospect and an area of structurally repeated quartz dolerite to the immediate east of the Bombora discovery.
The 2.2km Bombora discovery is likely to grow as a result.”
RC & Diamond Drill Program
The current drilling results relate to 31 RC holes (3,394m) and one diamond drill hole (387.4m) focused on the main 2.2km discovery zone at Bombora (BBRC0262-0278, BBRC0304-0317 and BBDD0007).
The drill holes are shown in plan, cross-section and long section on Figures 1 to 4. A listing of new assay results above a nominal 0.5g/t Au (calculated using a 0.2g/t lower cut-off grade) is provided in Appendix 1. Further details of the RC and diamond drilling are provided below and in Annexure 1.
The down-hole intersections reported do not represent true width as the geometry of the mineralised structures is still being resolved in several areas. Similarly, drilling in some areas is not
adequately “seeing” mineralisation that is angled sub-parallel to the drill direction.
Better RC drill intersections are highlighted on Figures 1 to 3 and include:
Analysis of Results
The thick, shallow, high-grade RC gold results encountered continue to upgrade the continuity of gold mineralisation, significantly enhancing the mining potential.
The higher density of drilling in conjunction with orientated diamond drill core is starting to clarify several mineralisation controls. This reinforces the substantial untested gold potential at depth, and also the untested potential over large areas along strike from the main 2.2km Bombora discovery.
The untested depth potential is highlighted in Figure 3 which shows several “stacked”, strongly mineralised, flat, vein arrays in long section that are spatially associated with a shear zone
identified in orientated diamond drill core. This configuration is expected to continue with depth.
Further areas of apparent north-plunging mineralisation are also evident to the north and south.
The untested strike potential is highlighted in Figure 4. A developing understanding of the mineralisation controls indicates that gold mineralisation dips to the west in several areas
peripheral to (and locally within) the main 2.2km Bombora discovery. As a result, these areas are largely untested by the wide-spaced, west-orientated reconnaissance drilling undertaken
These areas include:
(i) north-east trending areas in the Bombora South Prospect;
(ii) parts of the Crescent Prospect directly north of the Bombora discovery; and
(iii) an area to the immediate east of the Bombora discovery, where the mineralised quartz dolerite is repeated by faulting (eg. 6601400N).
Where the west-orientated drilling has intersected west-dipping lode mineralisation and drilled down it, the results indicate that these lodes can have good down-dip continuity, a pre-requisite
for the long term underground mining potential (eg. 6603000N; ASX Release 27 March 2017).
The 2.2km Bombora discovery is open along strike and depth and forms part of a 6km-long gold system that is itself open along strike (Figure 4). Many significant gold intersections situated along strike from the Bombora discovery are “floating in space” due to the wide-spaced, reconnaissance nature of earlier drilling.
The Bombora discovery is hidden below thin transported cover (typically 5-10m). Gold typically occurs as sulphide-rich lode and stockwork mineralisation in an upper, iron-rich part of a
fractionated dolerite, the Bombora Dolerite. The sulphide lodes have three dominant orientations and represent sulphide-impregnated fault zones (fluid pathways) with up to 10% pyrrhotite and pyrite accompanied by silica, albite, biotite and carbonate alteration and (tensional) quartzpyrite veinlets that can form stockwork-style mineralisation commonly associated with the sulphide lodes.
Next Steps for Breaker Resources
Resource drilling is currently underway with two RC rigs and one diamond rig focused mainly on resource delineation drilling in the 2.2km-long Bombora discovery area.
The planned RC drilling will progressively close the drill hole spacing to a 40m x 20m pattern, building a detailed picture of the mineralisation controls as it progresses. This will lead to deeper diamond drilling to further test the long term underground mining potential.
Selective RC drilling is also planned to assess the economic potential of west-dipping (and other) mineralisation geometries at the Bombora South and Crescent Prospects situated along strike
from the main Bombora discovery. Success will lead to additional resource-orientated drilling outside the main Bombora discovery zone.
Diamond drilling will continue to focus on structural orientation, validation and obtaining samples for preliminary metallurgical testwork prior to drilling of deeper targets, some of which will initially be undertaken with the RC drill rigs. The diamond drilling will be 50% funded (up to $150,000) under the WA Government’s Exploration Incentive Scheme 2016/17 Co-Funded Drilling Program grant awarded to the Company in the June 2016 quarter. The drill funding excludes any drilling relating to validation and metallurgical testwork.
An aircore drill rig will arrive in approximately one week to commence testing several targets located along strike from the current known 6km-long Lake Roe gold system shown on Figure 4.