HCh Package for Geochemical Modelling

(HCh for Windows)

• Introduction
• Geochemical applications
• Main features
• Ordering information
• Release information
• Related factsheets
• Related links

Introduction

Geoscience Australia in collaboration with Dr Yu Shvarov distributes the HCh software package for geochemical modelling.

HCh brings the power of equilibrium thermodynamic modelling to the desktop of research geologists, academics or post-graduate earth-science students. Although not limited to geological applications, the HCh package was developed primarily to simulate a broad variety of hydrogeochemical and geochemical processes. The software provides an efficient tool for fast examination of what-if scenarios in aqueous and hydrothermal geochemistry and can be used as an aid in formulating, refining and verifying relevant genetic models.

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Geochemical applications

The HCh package enables the user to:

• Analyse and predict ore distribution patterns and alteration zoning at hydrothermal deposits;
• estimate the relative viability of possible mechanisms of mineral and ore precipitation (eg, water-gas-rock interaction, fluid mixing, gas partitioning and fluid boiling);
• calculate the composition of natural, mine-site and hydrothermal waters for a specified geological environment and processes;
• calculate the solubility of ore elements (eg. Pb, Zn, Cu, Au, Ag, U) for particular geological conditions; and
• solve a range of auxiliary geochemical problems

Exploration geologists may be interested in using the software at the project-generation stage.

Experimentalists can use the package for planning hydrothermal experiments and quantitative interpretation of experimental results.

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Main features

The equilibrium compositions of multi-phase chemical systems are computed using the free-energy minimisation technique. The possible calculations cover a temperature range from 0-1000°C and a pressure range from 1-5000 bar. Model chemical systems can incorporate any combination of the following phases of constant and variable composition:

• Pure solids (minerals), liquids and gases;
• an aqueous solution (including a supercritical aqueous phase);
• a gaseous mixture (ideal mixture of ideal gases or Peng-Robinson mixture);
• liquid non-aqueous solutions (ideal or non-random two-liquid model);
• solid solutions (ideal multi-site mixing); and
• custom-defined solution phases.

For more details please view a summary of the HCh specifications.

HCh is user-friendly and self-explanatory. No prior knowledge of numerical computer modelling or programming is required to use the package but a good knowledge of hydrothermal geochemistry and ability to formulate well-defined chemical and geochemical models is helpful. The software was designed for personal computers running Windows operating systems, but can be successfully run on Mac computers simulating the Windows environment. The software is compatible with previous DOS versions of the package, including the thermodynamic database (UNITHERM) files and problem-setting modelling files.

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Ordering information

The software (Catalog No 65343) is available at a cost of A$737 plus postage and handling charges. An upgrade from a registered DOS version (Catalog No 65457) is available at A$368.50. To purchase HCh, please contact the Geoscience Australia Sales Centre or use the online order form. To obtain a free demonstration version of HCh, please contact Evgeniy Bastrakov.

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Release information

• Currently available:
• Version 4.1 for Windows (October 2007)

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Related factsheets

• HCh specifications

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Related links

• Virtual centre for geofluids and thermodynamic data
• Fluids inclusion database project
• FreeGs project
• FreeGs thermodynamic calculator
• HCh package for geochemical modelling