The Relationship of Sphalerite with Gold and Zinc

A Canadian mining company recently reported that their drilling operation has intersected semi massive and massive sulphide mineralization in their drill holes. The presence of sphalerite and chalcopyrite were confirmed with a handheld XRF analyzer.

Sphalerite is a mineral that is the chief ore of zinc. It consists largely of zinc sulfide (ZnS) in crystalline form but almost always contains variable iron content. It can also contain trace amounts of cadmium, gallium, and indium. It is commonly associated with minerals such as galena, pyrite, and fluorite in hydrothermal veins and sedimentary deposits. It can be mined for various reasons.

Sphalerite and Gold

Sphalerite can be associated with gold mining in several ways:

Geological Association: Sphalerite is often found in the same hydrothermal vein deposits as gold. These deposits may contain a variety of sulfide minerals, including sphalerite, galena (lead sulfide), and pyrite (iron sulfide), alongside gold.
Indicator Mineral: In some cases, the presence of sphalerite during exploration can indicate the potential presence of gold. Geologists might use sphalerite as a pathfinder mineral to help locate gold deposits.
Byproduct of Mining: In gold mining operations, especially in polymetallic deposits, sphalerite may be extracted as a byproduct. While the primary focus might be on gold recovery, the zinc from sphalerite can also be economically significant.
Ore Processing: In the milling and processing of gold ores, sphalerite and other sulfide minerals can complicate the extraction process. Special techniques such as flotation may be used to separate these sulfide minerals from the gold.

Overall, while sphalerite is not mined for gold, its occurrence in gold-bearing deposits can influence mining strategies and economic considerations.

Sphalerite and Zinc

But gold is not always the goal. Sphalerite is primarily processed to extract zinc, which is used in a wide variety of applications, including galvanization, die casting, chemical manufacturing, and battery production, among other things. Zinc is also a key component in the production of various alloys, such as brass (zinc and copper) and nickel silver.

Sphalerite must go through a series of steps involving concentration and smelting. After being mined, the ore is crushed and ground to liberate the sphalerite particles from the surrounding rock, then it is subject to froth flotation, roasting, leaching, purification, eletrowinning, melting and casting.

How XRF Technology Can Help Identify Sphlarerite

Whether the goal is to produce gold or zinc, portable XRF analyzers are effective tools for identifying and quantifying the elemental composition of minerals, including sphalerite. These devices allow geologists and miners to conduct on-site analysis quickly, providing immediate feedback without the need for laboratory testing. This can be particularly useful in exploration and mining operations.

X-ray fluorescence (XRF) technology works by irradiating a sample with X-rays, exciting the atoms and causing inner-shell electrons to be ejected. The resulting vacancies are filled by electrons from higher energy levels, releasing fluorescent X-rays that are characteristic of the elements present – like a fingerprint. The XRF instrument detects and measures these X-rays, analyzing the data to determine the types and quantities of elements in the sample, providing a non-destructive and rapid method for elemental analysis.

Portable XRF analyzers can detect the presence of zinc (Zn) and sulfur (S), which are the primary elements in sphalerite (ZnS). They can also detect other elements that might be present as impurities, such as iron (Fe), cadmium (Cd), and gallium (Ga).

Summary

With or without the XRF analysis, there is no guarantee of a mineral discovery. The company noted in its press release that the “Portable X-Ray Fluorescence (“pXRF”) data is exploratory in nature and is used predominantly as an internal workflow to assist in target prioritization and mineral identification through an early phase of exploration investigation. pXRF data is not provided as it is not an indicator of representative geochemistry of the entire rock mass and therefore should only be viewed as an initial screening prior to laboratory assays.” (Read the press release.)