Minerals extracted from the lithosphere — AQA A-Level Environmental Science

Mineral extraction from the lithosphere provides critical non-renewable resources essential for global infrastructure, technological development, and the transition to renewable energy. Understanding the geological formation and spatial distribution of ores underpins our ability to locate reserves using advanced remote sensing and geophysical surveying techniques.

Crucially, this topic examines the environmental trade-offs of extraction, ranging from habitat degradation and mine drainage to energy-intensive processing. It evaluates sustainable management frameworks, including Lasky's principle, cut-off grade dynamics, phytomining, and circular economy strategies aimed at mitigating lithospheric depletion.

• →Distinction between geological resources (total crustal quantity) and reserves (economically and technically extractable deposits).
• →Lasky's Principle of ore quality: lower grade ores are available in exponentially greater quantities than high-grade ores.
• →Geophysical exploration methods including gravimetry, magnetometry, seismic surveys, and satellite multispectral imaging.
• →Environmental hazards of exploitation: acid mine drainage (AMD), heavy metal contamination, spoil instability, and dust generation.
• →Alternative extraction and circular technologies including bioleaching, phytomining, cradle-to-cradle product design, and urban mining.

• Defines a metal ore as a rock or mineral deposit containing metal at a concentration that makes extraction economically viable.
• Distinguishes native metals, such as gold, from metals combined in compounds such as oxides and sulfides.
• Identifies that ore grade and market price determine whether a deposit is economic to extract.
• Recognises that processing, such as smelting or chemical separation, is needed to recover metal from ore.

• 💡Read the question stem for the key term, such as ore grade or native metal, before choosing an option.
• 💡Eliminate options that confuse a metal with the mineral compound it is extracted from.
• 💡Check whether the option describes economic viability, which is central to the definition of an ore.
• 💡Always specify whether you are discussing open-cast (surface) mining or deep-shaft underground mining, as their respective environmental impacts (such as land take versus ground subsidence) differ substantially.
• 💡Use precise terminology when discussing geochemical remediation; state 'neutralising sulfuric acid with crushed calcium carbonate' rather than just 'treating the water'.
• 💡In extended response questions on mineral security, always balance technological solutions (e.g. bioleaching) with practical economic limitations like slow processing rates and low extraction yields.

• Confuses a metal with its ore; state that the ore is the mineral deposit from which the metal is extracted.
• Assumes every metal-containing rock is an ore; note that economic viability depends on grade and cost.
• Treats all metals as occurring natively; recognise that many occur combined in oxide or sulfide minerals.
• Believing all discovered mineral deposits are classified as reserves: deposits are only reserves if economic conditions and current extraction technologies make extraction profitable.
• Assuming that mining lower-grade ores simply requires digging slightly more rock: Lasky's principle means processing exponentially more rock, requiring significantly greater energy, water, and resulting in massive spoil generation.
• Confusing spoil heaps with tailings: spoil refers to discarded overburden and waste rock extracted during excavation, whereas tailings are the fine slurry residue remaining after chemical or mechanical mineral processing.

1. 1Week 1, Days 1-3: Master key definitions (reserves vs resources, cut-off ore grade) and practice applying Lasky's principle to quantitative extraction curves.
2. 2Week 1, Days 4-7: Study exploration techniques (gravimetry, magnetometry, seismic) and create a comparative table of open-cast vs underground mining impacts.
3. 3Week 2, Days 1-4: Detailed case studies of mine remediation (acid mine drainage chemistry, phytomining, bioleaching, and circular recycling schemes).
4. 4Week 2, Days 5-7: Practice timed AQA 6-mark and 9-mark evaluation questions focusing on the economic vs environmental feasibility of exploiting low-grade ores.

• 📋Quantitative Lasky's Principle and ore grade calculations: Practise calculating reserve changes, percentage mass yield, and waste-to-ore ratios.
• 📋Comparative environmental impact questions (6-9 marks): Evaluate the relative ecological disruption, atmospheric impacts, and water contamination of surface versus subsurface mining.
• 📋Evaluation of alternative extraction techniques: Assess the viability of phytomining or bioleaching over conventional smelting for low-grade polymetallic deposits.