Nettle Creek Tin Dredge facts for kids
Quick facts for kids Nettle Creek Tin Dredge |
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Nettle Creek Tin Dredge, 2009
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| Location | Nettle Creek, Innot Hot Springs, Tablelands Region, Queensland, Australia |
| Design period | 1940s - 1960s (post-World War II) |
| Built | 1957 |
| Official name: Nettle Creek Tin Dredge, Barrytown 2 Dredge, Barrytown Gold Dredge, Battle Creek Tin Dredge | |
| Type | state heritage (built) |
| Designated | 22 September 1995 |
| Reference no. | 601534 |
| Significant period | c. 1937, 1954-1957 (fabric) 1957-1992 (historical) |
| Significant components | pontoon, machinery/plant/equipment - mining/mineral processing, crane / gantry |
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The Nettle Creek Tin Dredge is a large, old machine that used to dig for tin. It is located at Nettle Creek, near Innot Hot Springs in the Tablelands Region of Queensland, Australia. This dredge was built in 1957. It is also known by other names like Barrytown 2 Dredge or Barrytown Gold Dredge. Because it is an important part of history, it was added to the Queensland Heritage Register on 22 September 1995.
Contents
A Brief History of the Dredge
In August 1949, a company called Alluvial Gold Co Ltd bought land near Battle Creek and Nettle Creek. These areas, located between Ravenshoe and Mount Garnet in North Queensland, had lots of tin hidden in the ground. The tin was found in the old creek beds.
People have been mining for tin in the Mount Garnet area since 1881. Tin is found as a mineral called cassiterite. Big machines called bucket line dredges started working on other creeks nearby in the 1930s and 1950s.
How the Dredge Came to Queensland
The Nettle Creek Tin Dredge was first designed in England. It was built around 1937 in New Zealand. There, it was used to dig for gold and was called the FW Payne. All its original parts, including its electric motors and a large crane, came from Britain.
In 1954, the Alluvial Gold Co Ltd bought the dredge. It was taken apart in New Zealand and shipped to Cairns, Queensland. From Cairns, it traveled by train to Mount Garnet. A new floating base, called a pontoon, was built for it at Battle Creek.
The dredge was changed quite a bit to make it suitable for mining tin in Queensland. For example, it needed a special conveyor belt. This belt helped put the top layer of soil back over the dug-up areas. This was important for fixing the land after mining. The dredge was designed to dig about 20 feet deep for soil and 40 feet deep for the tin-rich sand.
Working Life of the Dredge
The dredge was put back together and started working at Battle Creek in November 1957. It was very successful and worked almost non-stop, 24 hours a day, 7 days a week. About 70 people worked on it in four different shifts.
In February 1965, the dredge finished its work at Battle Creek. It was then taken apart again. A new pontoon was built for it at Nettle Creek. From 1965 until 1992, the dredge worked its way down Nettle Creek. It eventually reached its final resting spot.
Bucket line dredges like this one first became popular for gold mining in New Zealand in 1877. Later, they were used more in California. From gold mining, their use spread to tin mining in places like Malaysia and Indonesia. These dredges are good at handling big rocks and wood, better than other types of digging machines.
Finding Tin Ore
Tin ore is a mineral called cassiterite. It looks like brown or black grains. You often find it mixed with gravel in old or current creek beds. This happens because water washes the tin out of rocks and carries it downstream. Cassiterite is nearly 80% pure tin. After it's dug up and cleaned, it's sent to factories. There, it's melted down and turned into metal bars. Tin is mostly used to coat metal cans, but it's also important for making alloys and solder.
Because there isn't much tin ore in a single spot, dredges have to dig up huge amounts of material. Tin deposits are usually not too deep. By testing the ground, miners can figure out how much tin is likely to be there. If there's enough water, using a dredge is the cheapest way to mine the tin.
How a Bucket Line Dredge Works
A mining dredge is like a floating factory. It has a digging machine, a way to sort and wash the material, and a plant to separate the tin. All these parts are built on a large floating base called a pontoon.
The dredge does four main things:
- It digs up the soil and gravel.
- It sorts the material into different sizes using a spinning screen.
- It cleans the finer material to get the heavy tin out.
- It puts the waste material back behind the dredge.
The dredge floats in a pond that it creates as it moves. It digs at the front and drops the cleaned waste at the back. This way, the pond moves along with the dredge. The digging part is a long chain of strong steel buckets. This chain hangs at an angle, usually about 45 degrees. The buckets scoop up the material.
As the buckets go over the top, they dump the material into a chute. This chute sends the material into a spinning screen, called a trommel screen. Here, strong jets of water wash the material. The small, tin-rich pieces fall through holes in the screen. The larger pieces continue over the screen and are sent away as waste.
The small, tin-rich material then goes to a special cleaning area. At Nettle Creek, this area had machines called pulsating jigs. These jigs helped separate the heavy tin from the lighter sand. The tin was collected for more cleaning, and the leftover material was sent out the back of the dredge.
The large waste material from the spinning screen goes onto a conveyor belt. This belt is on a movable arm at the back of the dredge, often called a stacker. It drops the waste material behind the dredge. Usually, this waste is just left in piles. However, at Nettle Creek, there was a rule to fix the land. The dredge had to dig up the topsoil first. This topsoil was sent on a separate conveyor belt directly to the stacker. It was then dropped on top of the waste piles. Later, a bulldozer would flatten the area. This helped return the land to its original state, ready for farming.
What the Dredge Looks Like Now
The Nettle Creek Tin Dredge is about 14 kilometers east of Mount Garnet. It's also about 6 kilometers south of Innot Hot Springs. To see it, you need permission from Woodleigh Station.
The dredge is very large. It is about 47 meters long, 23 meters wide, and 20 meters tall above its floating base. The base itself is 1.9 meters deep. The dredge is made of a steel frame with three main levels. It is currently sitting on the ground in its pond. Most of its metal siding has fallen off.
All the electrical parts have been removed. Only four of the original eleven cleaning machines (jigs) are left. The large Vaughan gantry crane is still on the top level. Two Richardson engines are on the bottom level. All the digging buckets have been taken off.
The dredge is at the very last place it worked. It sits in a pond that is partly blocked by an earth dam. If you look north along Nettle Creek, you can still see where the dredge worked. It left a wide, sandy path with hardly any trees or bushes.
Why the Dredge is Important
The Nettle Creek Tin Dredge is listed on the Queensland Heritage Register because it's important for several reasons.
It shows how Queensland's history developed. The Mount Garnet area was one of the first places in Far North Queensland where tin was mined. This mining was very important for the economy of the region. The dredge helps us understand this part of history.
It shows what a bucket line dredge is like. Even though it's old, the Nettle Creek Tin Dredge still shows how bucket line dredging worked. This was a common way to get tin from the ground. The dredge and its pond are the best examples of this type of tin mining left in Queensland. It also shows how mining equipment could be changed. This dredge was first used for gold in New Zealand, then for tin in Queensland. It reminds us that the mining industry could change a lot, depending on the price of metals.
