CIV2403 Geology & Geomechanics

CIV2403 S2, 2022 Geology Assignment.

An existing mining company wants to establish the potential for tin and rare earth elements within the Gibson region.  A feasibility study requires the regional geology to be understood, particularly with regards to calculating any tin resource that may be constrained by the geological resource model.

Task A) Regional Geology Task (2 pages):

A geological column needs to be established and the geology history of the region also needs to be determined. With respects to the geological history, any pertinent information, faults and unconformities that exist within the region should be included (Figure 1; Appendix 1).  Within the brief summary (2 pages) of the geological history of the region, the tectonic setting(s) should also be noted. The brief summary includes the geological column that has the oldest unit at the base and the youngest at the top.  It may be helpful to also identify structural features, such as any faults, within this column.

Factors to be identified within the geological history include unconformities, igneous events, deformational events, metamorphic grade and movement along faults.  The plate tectonic setting(s) need to be identified, where possible. Evidence needs to be included regarding the principle of superposition for the geological history and appendices may be used. Sketching the off-shore geology will help constrain aspects of the geological history and assist in completing Task C. (40 marks)

Task B) Cross Sections (1 or 2 pages):

Three cross sections, with no vertical exaggeration, need to be constructed that best highlights the geology of the region, including the extent of the tin resource, folds and faults within the region (1 page):

1. An initial cross section needs to be constructed along A-B.

2. A second cross section to be constructed along B-C.

3. A third cross section to be constructed along C - D. (60 marks)

Task C) Basement Maps

Construct a geological map that shows the geology under the ocean.

· Infer the geological boundaries, including faults for the region under the water.

· On the land show the metamorphic aureoles index mineral facies zonation associated with these as they get closer to the igneous intrusions.

· Determine the extent of the metamorphic aureole associated with the igneous rocks under the water.

· Compare geophysical techniques that could be used to confirm the veracity of your proposed geological map at depth. (60 marks)

Task D) Tin Resource Estimate and Potential Offshore Exploration (2 pages)

Estimate the tin resource based on the geological modelling that has been undertaken. Typically tin occurs in carbonaceous rocks juxtaposed next to felsic intrusions. While this will be only a rough initial estimate the company expects the following to be factored in:

· Average Economic Sn Cut-off Ore Grade: 0.45% (Appendix 2)

· Mining Depth: 220m.

As the rare earth minerals are becoming increasingly valuable, the company has requested you define further exploration areas of tin and rare earth element mineralisation extrapolated from existing information and located offshore. (40 marks)