Alto Metals Ltd acquired all of the issued capital of Sandstone Exploration Pty Ltd (Sandstone) in June 2016. Sandstone’s only asset, the Sandstone Gold Project, covers approximately 75% of the Archaean Sandstone Greenstone Belt in the East Murchison Mineral Field in Western Australia and is centred on the small township of Sandstone.
The area covered by the Sandstone Gold Project was formerly part of Troy Resources Ltd’s (ASX: TRY) Sandstone Gold Operations, which was highly profitable up until the cessation of mining in late 2009.
Alto’s first obective at Sandstone is to delineate relatively shallow oxide gold mineralisation that can be economically mined and trucked to one of several gold treatment facilities in the region. The second objective is to delineate deeper and more extensive high-grade sulphide-hosted gold mineralisation using RC and diamond drilling.
To support these objectives, Alto commenced in late 2016 a variety of broader exploration initiatives including acquisition of high-resolution airborne magnetic and radiometric data, litho-structural interpretation and targeting, Induced Polarisation (IP) surveys, and established an external research advisory committee (ERAC).
The ERAC is chaired by Emeritus Professor David Groves and was established to oversee Alto’s research and development (R&D) activities. The committee consists of a multi-disciplinary team of geoscientists, and a primary researcher based at The University of Western Australia. The scope of the ERAC is to incorporate traditional and emerging exploration techniques and technologies for testing on Alto’s project areas. The Sandstone Belt has been the focus of limited research to date, in comparison with other similar greenstone belts. The team is developing an understanding of the mineralising systems of the Sandstone Greenstone Belt.
Alto considers that the robust Australian gold price and current competitive cost environment will enable it to consider several areas for early recommencement of mining.
Since the discovery of gold at the end of the 19th Century, the Sandstone Greenstone Belt has produced over 1.2 million ounces of gold from numerous underground and open pit mining operations. Of this, some 612,000 ounces was produced between 1994 and 2010 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 Oaks Reef, Vanguard, Ladybird, Maninga Marley, Sandstone North, Oroya, Tiger Moth, Musketeer, Piper and Bulchina.
Between 1994 and 2010, the exploration focus at Sandstone was largely on exploring for and mining shallow oxide ore to feed the Herald/Troy Nunngarra Mill, at a time when the Australian dollar gold price was substantially lower than it is today.
Alto’s Exploration Program
In late November 2016, Alto commenced a limited reverse circulation (RC) and aircore (AC) maiden drilling program (3,827 metre RC and RC/AC) to provide a preliminary test for possible extensions to shallow oxide gold mineralisation at the Indomitable and nearby prospects, previously identified by Troy Resources Ltd (Troy), and to test induced IP anomalies immediately north of the Lord Nelson and Lord Henry deposits for sulphide associated mineralisation. Refer ASX announcements for results of progressive drilling programs.
More extensive RC and AC drilling programs are planned to commence in March 2017.