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 2008, 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’s experienced management and technical team has a track record in discoveries and is supported by an External Research Advisory Committee (ERAC) chaired by Professor David Groves.
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 2017 drilling 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.
Alto has now planned a succession of systematic focused drilling campaigns in 2018 to discover additional oxide and primary gold mineralization, towards delineating an initial one million ounce gold (JORC 2012) mineral resource as part of its overall objective to re-establish mining at Sandstone.
Refer ASX announcements for results of progressive drilling programs.
Alto’s existing Mineral Resource base, estimated by Snowdens, is shown in Tables 1 & 2 below.
Table 1. Lord Nelson & Lord Henry (JORC 2012) Mineral Resources
|Lord Henry Total||1,348||1.6||69|
Table 2 . Other Alto (JORC 2004) Mineral Resources
|Bull Oak Reefs||Inferred||390||1.5||18.8|
Cautionary Note: A Competent Person has not completed sufficient work to accurately classify the JORC 2004 estimates as Mineral Resources under the JORC 2012 Code