Brazilian gold explorer BBX Minerals’ shares are flying after metallurgical test work on drill samples returned results including 23.51g/t gold and 2172.5g/t silver — despite clarifying that these could not be considered assay results.

The assay process is used analyse minerals in ore to determine its composition or quality, often to help establish a project’s resource.

BBX (ASX:BBX) shares were up nearly 20 per cent to 19c after announcing the metallurgical test results from bulk samples at its Três Estados and Ema prospects in southern Amazon.

Anything above about 5g/t gold and 50g/t silver is considered high-grade.

The company cautioned that the results did not represent the total metal values in the samples, “but rather physically extractable gold based on the various recovery methods being tested”.

The BBX Minerals (ASX:BBX) share price has traded between 12c and 36c over the past year.
The BBX Minerals (ASX:BBX) share price has traded between 12c and 36c over the past year.

BBX went into a trading halt for five months to January after it was asked by the ASX to clarify an announcement it made regarding “spectacular gold extraction” results from Ema.

BBX told investors in August last year that an initial pyrometallurgical test conducted on 5kg of a bulk sample taken from the project had delivered extremely high grades of 299.3g/t of gold and 1971.6g/t silver.

The ASX questioned BBX over its methods in preliminary metallurgical testing work, noting that it had conducted the work without the release of quality-testing (or “assay”) results and asked for a reason.

“Despite extensive development work conducted in laboratories in Brazil, Australia and Canada, BBX has been unable to produce consistent, reproducible analytical results from the mineralised rock located on its Apui projects,” the company announced at the time.

“The company is therefore focusing on extracting the precious metals from bulk samples of this complex mineralisation in order to provide a reliable estimate of the recoverable precious metal content.”