Details of Award
NERC Reference : NE/R007772/1
Predicting ore mineralization using quantitative forward modelling and high resolution analytical data
Training Grant Award
- Lead Supervisor:
- Dr D Kohn, University of Glasgow, College of Science and Engineering
- Grant held at:
- University of Glasgow, College of Science and Engineering
- Science Area:
- Earth
- Marine
- Overall Classification:
- Earth
- ENRIs:
- Natural Resource Management
- Science Topics:
- Earth Resources
- Faulting
- Geomechanics
- Hydrothermal fluids
- Mineral deposits
- Ore deposits & mineralisation
- Abstract:
- The main objectives of this study are to understand fluid flow, fluid mixing and ore mineralization in the Navan Zn+Pb orebody in order to predict the potential location of additional resources. Based on previous work, our hypothesis is that metalcarrying fluids from a deep source move up in semi-vertical pipes in the footwall of a larger fault system and then spread out horizontally into the sedimentary host to form the large ore deposits when the deep fluids mix with a shallow brine,charged with bacteriogenic sulfide. We will combine novel numerical modelling techniques with a detailed analysis of the world-class 3D dataset of the distribution of mineralization and isotope data in the Navan ore body coupled with a detailed microstructural study of the local ore structure. Fluids in the Navan ore body are thought to come from two sources, bacteriogenic H2S-bearing brines from the surface and hydrothermal fluids which have interacted with the basement and acquired metals (Zn+Pb) during a phase of Carboniferous extension. The tructural control of ore disposition implies that fluids travel along faults and fractures, however, horizontal stratigraphy-controlled flow has also been observed. It is not clear, how the fluids mix to form the deposit, how the fluid flow is taking place in detail and how flow and mixing influence the ore precipitation. In addition it is not clear how the metal-bearing fluids enter the system, multiple pathways exist at the level of the mine, but does this pattern represent multiple deeper sources or one pathway? In order to predict ore disposition one needs to understand in detail how fluids flow into and through the stratigraphy and deposit the ore, on multiple scales. In order to understand these dynamics we will use a state-of-the-art hydro-dynamic reactive numerical model that can deal with stressed systems, fracturing, fluid flow, advection-diffusion and replacement reactions to forward model mineralization (modelling platform Elle and Melange). In a novel approach we combine the model with the geochemical software Phreeqc (from the USGS) that can be used to calculate complicated reactions based on local P-T and redox conditions and that can deal with fluid mixing. These calculations will be used to trigger reactions in the model. We can then simulate mineralization on thin-section to meter scale in detail and can also study 2D slices through the whole ore-deposit. In this multi-scale approach we include realistic geological layers with variable elastic properties and porosities, faults with variable permeability and apply different fluid and stress boundary conditions in order to understand how the fluids mix and how they travel vertically and horizontally. We will develop an understanding of how the mixing takes place in detail in time and space and how these dynamics influence the ore deposition and disposition. The outcome of the numerical model will then be compared with the 3D dataset from Navan, which has been used by a previous student of Boyce successfully to estimate geometries of fluid migration (S isotopes and elemental geochemistry can readily distinguish the influence of the two fluids). The non-academic partner and the co-PI Boyce have the setup and experience to analyse the large 3D dataset of the mine with 3D-viewing software leapfrog. The final aim will be to derive a better understanding of the dynamics of the development of ore deposits in time and space in order to enhance possibilities for future predictions. Ultimately we thus hope our research will help deliver a new vectoring tool for predicting ore disposition. We have already implemented hydrodynamics, fracturing, advection-diffusion and reactions in Elle and have merged the code with Phreeqc. The code will have to be adjusted to the specifics of the Tara mine deposit, fluid and geometry, but is already functional, so that this task is well within the realm of a PhD researcher.
- NERC Reference:
- NE/R007772/1
- Grant Stage:
- Completed
- Scheme:
- DTG - directed
- Grant Status:
- Closed
- Programme:
- Industrial CASE
This training grant award has a total value of £89,917
FDAB - Financial Details (Award breakdown by headings)
| Total - Fees | Total - RTSG | Total - Student Stipend |
|---|---|---|
| £17,480 | £11,000 | £61,440 |
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