Sampling Program
*** (see bottom of page for new Bulk Sampling for Metallurgical Analysis comments) ***
As the mine has been gradually dewatered, refurbished and re-accessed, Levels 4 through 9 have been sampled and significant assays averaging over 68 grams of Gold per tonne have been recorded on 200+ ‘Channel Samples’ taken to date.
Morning Star's Channel Sampling typically involves 2->5kg individual rock samples running vertically down the face of the stope, including all types of available rock. This includes, reef, dyke and country rock depending on access and reef widths/types. The samples are spaced at between 5 metres and 8 metres and run along the drives, where access is good and not on a formal grid in areas where access is impaired.
The samples are extracted using pneumatic drills and taken to surface by the Deputy Exploration Manager for dispatch to a lab in Bendigo for assay.
Many individual samples have returned gold assays of higher than 500 grams of Gold per tonne (or over 15 Ounces of Gold per tonne), which is extraordinarily high, and also encouraging for economic mining potential of the areas sampled.
Most recently, the Morning Star Channel Sampling Program was conducted on dewatered areas between 7L and 10L. An area of historically noted significance to WMC known as the 7 Sub-Level, which was only partially developed at the time of 1939 Bushfires, has been re-accessed and sampled. This area is accessible only via a winze that runs from the 7L down to the 9L on the northern side of the Morning Star mine on the fringe of the famous Whitelaw's Reef. The 7 Sub-Level was earmarked for mining at the time but the 'Black Friday' bushfires & WWII conspired to leave it untouched. Detailed WMC records indicate grab samples between 2ozs and 4ozs to the ton. Recent sampling of the area by MCO confirmed the high grade potential and the partial development with no mining carried out - leaving an intact mineralised ore pocket which is being assessed currently for resource size and mining potential.
Reconnaissance Samples have also been taken on dykes within Morning Star’s Regional Tenements, which are close to Woods Point. To date, underground reconnaissance samples have been taken on the Comet and Little Comet Dykes and each sample taken has returned gold mineralisation. As these Regional priority dykes are increasingly sampled, MCO hopes to build a better picture of why these dykes were only mined to shallow depths above the water table. Samples are currently being taken at the All Nations dyke, which was historically richly mined for over 132,000 ounces of Gold.
MCO will conduct ongoing channel and reconnaissance sampling to map the overall mining potential and build the resource model whilst cross-referencing with historical WMC records. Assays reported between Q4 2006 to Q4 2007 period were of very high Au. Grades which in some cases, MCO’s Chief Geologist Dr. Peter Jackson, noted as indicating ‘economic ore targets’. See ASX Releases section for more info.
At all times it is Morning Star's intention to sample areas with potentially economic tonnages of host rock rather than remnant mined out areas of the mine. The sampling within the Morning Star mine has been a key driver of planning for the 'Gap Zone' Drilling Program taking place over 2008. The ultimate objects of the underground sampling program at the Morning Star mine are to locate a Bulk Sampling / Trial Mining Program for late 2008 and to increase resource definition overall in undeveloped areas of the mine leading to an initial resource statement & endowment calculation.
Click on this file for a Plan View of the 7 Sub-Level Sampling importantly showing proximal drilling intercepts (2005 & older).
7 Sub-Level Sampling Assays (160.53 Kb)
*** Bulk Samples Taken for Metallurgical Study & Plant Pre-feasibility Study ***
An initial program of three 100–150Kg composite samples to test Morning Star mine ore-grade material for ROM metallurgical recovery and grade factoring was processed in the 3rd Quarter 2007.
The bulk samples collected were representative of medium to high-grade laminated quartz vein ore and stock-work/breccia vein ore commonly found in the mine. The metallurgical testing has enabled Morning Star to better analyze the type, size and nature of gold distribution, along with the identification of suitable methods for recovery and anticipated gold recovery rates.
The results of the Bulk Metallurgical Tests have been outstanding.
1. Gravity gold recovery was extremely encouraging (between 78% and 93% depending on the crush coarseness).
2. At a coarse 250microns crush, Morning Star found that the bulk samples returned up to 88% gravity gold recoveries through the first crush with up to 98% total recoveries after a short period of leaching (8 hours) and greater than 99% recoveries after 24 hours.
3. Head Grades from the samples were strong as expected. The grades obtained in the three bulk samples were between 27 grams per tonne and 35 grams per tonne. Samples were blended with lower grade material made up of sediments and dyke to give a more representative 'mining grade' sample to analyse.
One of the key aspects of the results to date, is that in any future planned mining operations, Morning Star feels confident that a mill and plant set to crush ore at 250microns rate would significantly reduce Capital and Operational Expenditures for the company and enable it to operate well under industry average gold production costs per tonne.
So encouragingly for MCO, not only are there rich remnant reefs as proven to date via the Channel and Reconnaissance sampling program, but gravity gold returns are very high, giving rise to a ability to produce gold cost effectively and environmentally sensitively too. A composite sample of ROM ore has been sent to Gekko Systems in Ballarat to assist in pre-feasibility studies on trial mining at the Morning Star mine.
A graphical analysis of the gravity gold returns in a plant MCO is trialing is below.
