The Pozz Volcanic Ash Deposit was recognised by the Company as being of possible commercial interest during recent prospecting work in Nevada.
Pozzolans are usually evaluated against a standard published by ASTM International, a standards organization that develops and publishes consensus technical standards for a wide range of materials. ASTM Standard C618 defines the chemical and physical requirements for pozzolans, including Class “N” natural pozzolan.
All of the samples collected so far from the Pozz Ash Deposit exceed the chemical requirements of ASTM standard C618 by a significant margin and show remarkably consistent chemistry, even over a 2km distance. This chemical consistency is important to cement manufacturers wanting to produce a consistent product.
|Chemical Composition||ASTM C618 Chemical Requirements||Pozz Ash Chemical Analysis (Range in 8 surface samples)|
|Silicon dioxide (SiO2) plus aluminium oxide (Al2O3) plus iron oxide (Fe2O3)||Min. 70.0%||83.8-86.5%|
|Sulphur trioxide (SO3)||Max. 4.0%||0.01-0.03%|
|Loss on ignition, max. % 10.0||Max. 10.0%||5.21-5.78%|
The physical specifications of ASTM C618 are largely based on physical testing of a material in cement mixes and reflect the requirement for a high pozzolanic activity which, in a natural material, is a function not only of its chemistry but also its mineralogy (especially its degree of crystallinity) and its surface area.
The mineralogical characteristics of the Pozz volcanic ash suggest a high pozzolanic activity. It has a high content (80%) of reactive amorphous minerals (glassy, non-crystalline) and a large surface area.
Whereas some natural pozzolans are hard and need to be quarried by blasting and then crushed and ground before use, the Pozz volcanic ash is fine grained and friable, will not require any blasting or crushing and could be mined and processed at very low cost. The project area is also favourably located close to well-maintained roads and other infrastructure.
A mini-bulk sample was collected during the recent sampling programme and is now undergoing an initial physical testing programme.