Ultra Low Level Gold

 

Using the gold content of water as an indicator of surrounding deposits has long held the interest of the gold exploration industry. Being a more homogeneous medium than rock, a sample of water will be more representative of the water body than a rock sample will be of the surrounding geology. This means large areas can be explored with relatively few samplings, providing a cost effective exploration tool.

Hydrogeochemical analysis for gold exploration requires highly sensitive measurement techniques in order to detect the extreme trace levels of the metal, which is typically present at low parts per trillion (ppt) levels. The difficulties involved in reaching this level of precision have traditionally been prohibitive, and only in recent years has it become an economically viable possibility, due to advances in instrumental precision.

Ultra Trace are now capable of reaching the required levels of precision, by incorporating an Electro Thermal Vapourisation (ETV) system as the sample introduction system on our ICP-MS's. These ETV units are commonly used with Atomic Absorbtion Spectrophotometers (AAS) to enhance sensitivity, and are sometimes called Graphite Furnace systems. By coupling the ETV with our already highly sensitive ICP-MS instruments, we are now able to determine the gold content of water to a detection limit of 0.5 parts per trillion ( 0.0000005 ppm ). This precision can be achieved regardless of the Total Dissolved Solids (TDS) in the water.

The same equipment can be used to analyse the gold content of soil or rocks. The sample is pre-treated either by Cyanide Leach for a detection limit of 1 ppt, or by Aqua Regia Digest for a detection limit of 5 ppt.

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