Emily Ann and Maggie Hays nickel mines facts for kids
| Location | |
|---|---|
 Emily Ann and Maggie Hays nickel mines
Location in Australia
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| Location | Lake Johnston, Western Australia |
| State | Western Australia |
| Country | Australia |
| Coordinates | 32°13′15″S 120°29′45″E / 32.22083°S 120.49583°E |
| Production | |
| Products | Nickel |
| Production | 8,900 tonnes of concentrate |
| Financial year | 2008 |
| History | |
| Opened | 2001 |
| Closed | 2009 |
| Owner | |
| Company | MMC Norilsk Nickel |
| Website | http://www.nornik.ru/en/ |
The Emily Ann and Maggie Hays mines were places where people dug for nickel in Western Australia. They are located about 150 kilometers (about 93 miles) west of a town called Norseman, Western Australia. These mines were part of an area known as the Lake Johnston Greenstone Belt.
Mining at Emily Ann and Maggie Hays started in 2001. However, in early 2009, the company that owned them, Norilsk Nickel, stopped mining. This happened because the price of nickel dropped a lot, making it too expensive to continue.
Contents
How the Mines Were Found
Finding Maggie Hays
The Maggie Hays nickel deposit was first found in the 1970s by two companies, Anaconda Co. and Union Miniere. They were looking for nickel and found some signs of it in the ground. They drilled holes and found nickel spread out in the rocks. But they just missed the really rich, high-grade nickel ore, sometimes by only three meters!
Later, in 1996, a company called LionOre Australia started working on the Maggie Hays deposit. Their geologists (scientists who study rocks and the Earth) used special tools that send out electromagnetic waves. These waves helped them find hidden rocks that conduct electricity, which often means there's metal there. They drilled deep holes based on these signals and finally found the main nickel ore.
It's believed that the first companies missed the main nickel because they gave up their land when nickel prices were very low.
Finding Emily Ann
The Emily Ann nickel deposit is about 1.2 kilometers (about 0.75 miles) north of Maggie Hays. It was found in 1998 after a lot of searching using the same electromagnetic tools.
Finding Emily Ann was a big success for the geologists. The nickel ore here was shaped like a flat, bent rock layer. It was also found in a type of rock called felsic gneiss, which doesn't conduct electricity well. This made it harder to find, but the tools worked! The top parts of the ore were also closer to the surface, about 200 meters (656 feet) deep, which helped.
What made Emily Ann special was that the nickel ore had moved far from where it usually would be found. It was in a spot not normally expected to have nickel.
The Rocks Around the Mines
The rocks where the Maggie Hays and Emily Ann mines are located are part of a very old area called the Lake Johnston Greenstone Belt. This belt is about 2.85 billion years old! It's made up of different layers of rocks.
- Ultramafic Rocks: These are special rocks called komatiites. They are very old and often contain nickel. In the Lake Johnston area, there are three main layers of these rocks. Most of the nickel is found in the middle layer.
- Other Rocks: Below the komatiites, there are thick layers of felsic gneiss, which are light-colored rocks. Above the komatiites, you can find layers of banded iron formation (rocks with layers of iron) and basalt (a common volcanic rock). There are also some sedimentary rocks (rocks formed from bits of other rocks).
Sometimes, you can find large, bowl-shaped rock formations called lopoliths in this area. These are thought to be old pathways where molten rock flowed up from deep inside the Earth.
The whole Lake Johnston Greenstone Belt has been squeezed and heated over billions of years. This process, called metamorphism, changed the rocks a lot. The rocks are also folded and broken by faults, which are cracks in the Earth's crust.
Mining Operations
Mining at Emily Ann began in late 2001. At that time, the mine was owned by a company called LionOre Mining International. Maggie Hays, which is about 3 kilometers (1.8 miles) south of Emily Ann, was partly owned by LionOre and another company called BHP Billiton. Mining at Maggie Hays started after Emily Ann was fully up and running.
In June 2007, a large company called MMC Norilsk Nickel took over LionOre. This meant Norilsk Nickel then owned all of LionOre's mines in Australia, including Emily Ann and Maggie Hays.
However, in early 2009, Norilsk Nickel stopped all its nickel mining in Australia. This included Emily Ann, Maggie Hays, and other mines like Black Swan, Cawse, and Waterloo. They closed down because the price of nickel dropped very sharply, making it unprofitable to keep digging.
Maggie Hays Mine Geology
The Maggie Hays nickel ore is found in a layer of ultramafic rock that is tilted towards the west. This rock layer is shaped like a "keel" (like the bottom of a boat) and goes deep into the Earth. The main nickel ore is made of very rich, solid layers of nickel sulfides, usually about 2 to 6 meters (6.5 to 20 feet) thick. These layers contain minerals like pentlandite, pyrrhotite, and pyrite.
The rocks in the Maggie Hays mine have also been changed by heat and pressure. This process created new minerals within the rocks.
Emily Ann Mine Geology
The Emily Ann nickel ore is found in a very different way compared to Maggie Hays. Here, the nickel sulfides are in a folded and highly squeezed rock unit. It's like a bent, overturned trough that goes gently towards the northeast.
The nickel sulfides at Emily Ann are found within a broken-up ultramafic rock unit that is stuck inside the lighter-colored felsic rocks. The nickel is often concentrated in the squeezed parts between these broken rock pieces.
The way the Emily Ann nickel is found is quite unusual. Normally, these types of nickel deposits are found much closer to the main ultramafic rock layer. But at Emily Ann, the nickel has moved far away, sometimes up to 600 meters (nearly 2,000 feet) from its original spot. Scientists think this happened because of intense squeezing and movement of the rocks deep underground.
