Alto’s Sandstone Project covers ~80% (800km2) of the historic Archaean Sandstone Goldfield 600km north of Perth in the East Murchison Mineral Field of Western Australia and is centred on the small township of Sandstone.
Historical Production and Exploration
Since the discovery of gold at the end of the 19th Century, the Sandstone greenstone belt has produced over 1.3 million ounces of gold from numerous underground and open pit mining operations. Of this, some 612,000 ounces was produced between 1994 and 2008 from the open-pit mining of shallow oxide ore by ASX listed companies Herald Resources Ltd and Troy Resources Ltd.
The numerous former open pits, prospects and gold occurrences now owned by Alto include Lord Nelson, Lord Henry, Havilah, Bull Oak, Vanguard, Ladybird, Maninga Marley, Sandstone North, Oroya, Tiger Moth, Musketeer, Piper and Bulchina.
Between 1994 and 2009, the exploration focus at Sandstone was largely on shallow oxide ore to feed the 1987 vintage Herald/Troy Nunngarra Mill, at a time when the Australian dollar gold price was substantially lower than it is today. With a higher gold price, an excellent database and a better understanding of regolith and the structural control on large gold deposits, Alto is confident of achieving its goal of 1 to 5 million ounces of gold.
Alto’s Exploration Program
Alto is using a 'minerals systems' approach and has identified a pipeline of high-priority litho-structural targets most likely to host million-ounce gold deposits. These target areas are being progressively assessed and ranked, using both the large legacy database which Alto has assembled from WA Mines Department Open File system, and by Alto's on-ground exploration including geophysics and drilling, which commenced in late 2016.
Of particular note is that Alto’s drilling programs in 2017 and 2018 confirmed the mineralized host rocks in Alto’s "Alpha Domain" and at Vanguard are comprised of differentiated dolerite, basalt and ultramafics, a combination synonymous with Kalgoorlie’s World Class Golden Mile Dolerite, the Mt Charlotte orebody and the Jundee gold deposit.
Refer ASX announcements for results of exploration programs.
Alto’s existing Mineral Resource base is shown in Table 1 below
Table 1. Sandstone Gold Project Mineral Resource Estimate as at 30th Sept 2019
|TOTAL INDICATED & INFERRED||5,380||1.7||290,000|
|Indomitable Camp + Vanguard Camp3||Inferred||0.3-0.5||2,580||1.5||124,000|
|Havilah & Ladybird4||Inferred||0.5||510||1.8||29,000|
Note 1. AME ASX Release 16 May 2017. "Maiden Lord Henry JORC 2012 Mineral Resource of 69,000oz."
Note 2. AME ASX Release 28 April 2017. "Lord Nelson Mineral Resource Increased to 68,000oz."
Note 3. AME ASX Release 25 Sept 2018. "Maiden Gold Resource at Indomitable & Vanguard Camps, Sandstone WA"
Note 4. AME ASX release 11 June 2019. "Alto increases Total Mineral Resource Estimate to 290,000oz, Sandstone Gold Project"
All material assumptions and technical parameters underpinning the 2017, 2018 and 2019 JORC (2012) Mineral Resource estimates in the above ASX announcements continue to apply and have not materially changed since last reported.