Exploration geochemistry is the study of the spatial distribution of elements and minerals in rocks, soils and river sediments. Economic mineral deposits can be found, particularly in terrains with little rock outcrop, through the identification and mapping of anomalous geochemical patterns in the overlaying soils, rocks and sediments. Geochemical surveys often permit a relatively quick and cheap way of determining whether an area has an elevated concentration of certain elements and minerals. This can be useful in eliminating non-prospective areas of an exploration license or can aid in identifying areas of interest for more in-depth sampling and investigation.
ARCHEAN geologists has recently completed such programs for copper-gold mineralization in Ethiopia and Sudan.
The major geochemical methods can be divided into methods for reconnaissance exploration and methods for detailed exploration.
Stream sediment sampling identifying possible sources of anomalous element concentration and can identify a drainage basin worthy of follow up in more detail. It’s very important for reconnaissance exploration when the intent is to discover areas favorable for ore using relatively widely spaced samples.
Soil sampling used to define a target for more expensive exploration as trenching and/or drilling. It’s very important for detailed exploration when the intent is to outline areas probably underlain by ore.
Rock chip sampling provides a direct sample of surface material for assay. It is just as important to determine the extent of mineralization as it is the mineralization itself. In addition, if an area appears visually barren of mineralization, take some representative samples, so as to confirm the barren nature – this makes relinquishing an area much easier and can be done with some confidence.
Trench sampling (also called costeaning) is a form of geochemical sampling where a shallow trench is dug then the exposed rock mapped, analyzed and sampled. Costeaning is only used in exploration for some minerals, including gold and lead. Strict regulations apply to costeaning and environmental safeguards ensure all sites are rehabilitated.
Archean does trenching to test bedrock and/or saprolite (i.e. weathered bedrock) above potential ore bodies to test the surface continuity of a mineralized zone.
Ensuring proper quality measurements in all aspects of the exploration phase is a priority for us. The Company continuously reviews data quality and routinely reviews and enhances its methods of monitoring quality.
Typically, QA involves the addition of “check” samples including blanks, duplicates, and standard samples.
Archean is undertaken Assay by outsource certified laboratories.
Geochemical maps-led interpretation of assay results using contouring and gridding in designated software programs, alongside a detailed understanding of the relationships between elemental concentrations in different sampled materials allows ARCHEAN to identify real anomalies amongst background values and vector in on the most prospective mineralized bodies.