The Bielsdown Project, located 12 kms north of Dorrigo in north-eastern NSW includes the Wild Cattle Creek antimony mine which was discovered in the late 1800's and mined intermittently on a small scale until the most recent mining in the 1970's. The deposit is hosted by a sub-vertical fault breccia within a sequence of metasediments. The high grade antimony-rich core of the structure is contained within a cemented (silicified) stibnite rich breccia.
The core is surrounded by a lower grade incohesive breccia. Previously these zones have been modeled together as a single mineralised zone, but in the current resource estimate they have been modeled separately. On both sides of the fault structure, lower grade antimony (chemical symbol Sb)can be found in stock-work (or stringer) style vein mineralisation along with tungsten, primarily in the form of wolframite.
Anchor's recent drilling defined and extended the target breccia structure, which hosts strong stibnite (antimony sulphide) mineralisation and is surrounded by a broader zone of stringer type mineralisation. Independent industry consultant, SRK Consulting (Australasia Pty Ltd) ("SRK"), has completed a three dimensional model and has estimated resources for the Wild Cattle Creek antimony deposit (ASX Announcement, 10 December 2010)according to the following table:
|
Sb Cut-off Grade (%) |
Category | Tonnage | Sb Grade (%) | Au Grade (g/t) | W Greade (ppm) | Sb Metal (tonnes) |
| 0.2 | Indicated | 550,00 | 2.13 | .22 | 240 | 11,600 |
| inferred | 1,040,000 | 0.85 | 0.13 | 423 | 8,900 | |
| Total | 1,590,000 | 1.29 | 0.16 | 360 | 20,500 | |
|
Sb Cut-off Grade (%) |
Category | Tonnage | Sb Grade (%) | Au Grade (g/t) | W Grade (ppm) | Sb Metal (tonnes) |
| 0.5 | Indicated | 500,000 | 2.30 | .22 | 252 | 11,400 |
| Inferred | 560,000 | 1.30 | .23 | 320 | 7,300 | |
| Total | 1,060,000 | 1.77 | .23 | 332 | 18.700 | |
|
Sb Cut-off Grade (%) |
Category | Tonnage | Sb Grade (%) | Au Grade (g/t) | W Grade (ppm) | Sb Metal (tonnes) |
| 1.0 | Indicated | 340,000 | 3.06 | 0.31 | 278 | 10,300 |
| Inferred | 270,000 | 1.94 | .33 | 259 | 5,300 | |
| Total | 610,000 | 2.56 | 0.32 | 269 | 15,600 |
SRK also completed a Scoping Study in early 2011 (AHR Announcement, 24 February 2011) which indicated that potential positive financial returns from the project could be enhanced if additional high grade antimony resources can be delineated. The existing high grade resources contained within the fault breccia zone are shown in the figure along with the potential down plunge extensions to be tested by new drilling.
Anchor plans to undertake a diamond drilling program consisting of 8 to 10 deep holes spaced on 60 metre sections to progressively step out and test for mineralisation down plunge. The program will involve approximately 4,000 metres of drilling and will commence as soon as land access agreements and regulatory approvals are in place.
Antimony occurs naturally in the environment and is a very important metal in the world economy. Antimony has been known since ancient times and is usually obtained from mining the ores stibnite (Sb2S3) and valentinite (Sb2O3). Antimony is a poor conductor of heat and electricity, is stable in dry air and is not attacked by dilute acids or alkalis. It has the important property that it expands on cooling.
Total world consumption in 2010 was 135,000 tonnes of antimony in metallic form, of which China produced nearly 90%. Flame retardants account for about 70% of antimony demand in the form of antimony trioxide and increasingly tougher standards for flammability protection along with increasing consumption of antimony as a stabilizer in plastics suggests continuing consumption growth. Other important uses are in paints, ceramic enamels, glass and pottery. High purity antimony is used to make semiconductors and is alloyed with lead, particularly in batteries, to increase lead's durability.
Antimony has been used in medicine for thousands of years and among its modern uses is its therapeutic efficacy in patients with acute promyelocytic leukemia and, with other compounds, in treating certain tropical diseases.
A significant new use for antimony is the development of a new generation of memory devices which will replace the flash drive memory devices presently used in computers, mobile phones and USB memory devices. These new devices (known as phase change devices) use an alloy of germanium, antimony and tellurium.
Moves in recent years to better regulate the antimony industry in China, which has the world's largest domestic demand and also the world's largest importer of antimony, have lead to local supply shortages but increase stability in the international markets. Demand is growing with antimony trioxide consumption rising 7.5% annually from 2004 to an estimated 180,000 tonnes in 2010. In June 2010, the European Commission identified antimony as one of the 14 minerals critical to European industry which are facing supply challenges. China has declared antimony a strategic metal.
Consequently there has been significant growth in the price of antimony from around US$1,000/tonne in 2000 to around US$15,000/tonne in 2011.