18-Geol-A1 Mineralogy and Petrology · December 2016
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
EGBC National Exam — Geological Engineering, 04-Geol-A1 Mineralogy and Petrology, 2016-Dec. Closed book; no calculator permitted. Part 1 requires all six 10-mark short-answer questions (60 marks); Part 2 instructs "answer 4 of the 7 ten-mark questions" (40 marks).
Reference texts: Klein & Dutrow, Manual of Mineral Science, 23rd ed. (mineral/silicate structural classification, ore mineralogy); Winter, Principles of Igneous and Metamorphic Petrology, 2nd ed. (magmatic differentiation, phase diagrams, metamorphic reactions and facies, AFM projections, volcanic processes, ophiolites and oceanic crust, subduction-zone/rift/hotspot melting); Nesse, Introduction to Optical Mineralogy, 4th ed. (index-mineral optics).
Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.
Each metal listed has one dominant simple oxide that is (or historically was) its principal ore mineral; two entries below note a common co-ore for completeness.
| Metal | Mineral | Formula | Notes |
|---|---|---|---|
| Tin (Sn) | Cassiterite | $\text{SnO}_2$ | The dominant tin ore mineral worldwide; dense and chemically resistant, so it concentrates readily in placer deposits as well as greisen/pegmatite-hosted primary ore. |
| Iron (Fe) | Magnetite | $\text{Fe}_3\text{O}_4$ | A major iron ore mineral, strongly ferrimagnetic (an inverse spinel, mixed $\text{Fe}^{2+}/\text{Fe}^{3+}$); hematite ($\text{Fe}_2\text{O}_3$) is the other principal iron oxide ore, dominant in banded iron formations. |
| Aluminum (Al) | Corundum | $\text{Al}_2\text{O}_3$ | The true Al-oxide mineral; most economic aluminum is actually refined from bauxite, a rock composed of aluminum hydroxide minerals (gibbsite $\text{Al(OH)}_3$, boehmite/diaspore $\text{AlO(OH)}$) rather than corundum itself. |
| Titanium (Ti) | Rutile | $\text{TiO}_2$ | A principal titanium ore mineral; ilmenite ($\text{FeTiO}_3$, a Fe-Ti oxide) is the other major Ti ore and is more abundant globally. |
| Uranium (U) | Uraninite | $\text{UO}_2$ | The primary uranium ore mineral; its massive, cryptocrystalline variety is historically called pitchblende. |
