engineering

Macraes Mine

Macraes Mine is a engineering topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Macraes Mine rather than just read about it. In short: Macraes Mine in East Otago is New Zealand's largest gold mine, and consists of a large scale opencast mine opened in 1990, and a newer underground mine, opened in 2008. It is situated close to the settlement of Macraes Flat and is owned by OceanaGold Corporation.

Key takeaways

Macraes Mine belongs to engineering; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Macraes Mine to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Macraes Mine from memory before moving on to harder problems.

Reference excerpt

Macraes Mine in East Otago is New Zealand's largest gold mine, and consists of a large scale opencast mine opened in 1990, and a newer underground mine, opened in 2008. It is situated close to the settlement of Macraes Flat and is owned by OceanaGold Corporation. Gold production averaged 193,000 Troy ounces/year for 2008 through 2010. Ore grades have been declining, to 1.26 grams/tonne in 2010, but recoveries have improved slightly to 81% of the gold contained in the ore, in 2010. From 1990 through 2014, gold production totaled about 4 million ounces. The mine's 5 millionth ounce was poured in July 2019. The company claims a gold reserve of 1.53 MM troy oz Au plus a larger subeconomic gold resource; and expects the mine to operate at least through 2021. As of July 2019, over 5 million ounces of gold have been extracted. The gold bearing rocks were formed by the orogenic processes that created the Otago Schist belt.

References

External links Macraes Mine Archived 12 April 2020 at the Wayback Machine at Oceana Gold Media related to Macraes Mine at Wikimedia Commons

Worked examples

Example 1 — a first encounter with Macraes Mine

Start with the simplest possible case. Write down what Macraes Mine claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Macraes Mine before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Macraes Mine ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Macraes Mine

In research: Macraes Mine appears in engineering research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Macraes Mine in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Macraes Mine is common in secondary-school and first-year university syllabi. It links to neighbouring topics Buildings and structures in Otago, Gold mines in New Zealand, Mine stubs, so understanding it makes those chapters shorter.
In everyday life: Look for Macraes Mine outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Macraes Mine in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Macraes Mine means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Macraes Mine out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Macraes Mine in simple terms?

Why does Macraes Mine matter?

Because it connects several engineering ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Macraes Mine?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Macraes Mine.