Mount Coot-tha Building Stones

 

Meta-sedimentary building stone sourced from Mount Coot-tha Quarry.

A few weeks ago, I put up a blog post about a Gold Mine Hike at Mount Coot-tha in Brisbane, Australia.  I wrote that the gold was found in meta-sedimentary rocks, but I didn’t show any good pictures of the rocks. This is because the rocks are highly weathered and also mostly covered with vegetation in the area where the hike is located.

This morning I went with my family to the Brisbane Botanic Gardens at Mount Coot-tha and noticed that many of the building stones used throughout the gardens are blue-gray meta-sedimentary rocks that are locally sourced from Mount Coot-tha Quarry. You can still make out the original sedimentary layers in many of these rocks, which are hornfels metamorphic grade. They were cooked by the intrusion of the Enoggera Granite. The meta-sedimentary rocks make lovely and also very durable building stones. They also make good road aggregate. Here are a couple of pictures of them in use in the gardens:

Decorative wall made out of meta-sedimentary rocks from Mount Coot-tha Quarry.

 

Another picture of the deocrative wall leading to the Tropical Display Dome building.

Building stones sourced from Mount Coot-tha Quarry are used as decorative building stones in many places throughout Brisbane. I’ll share more pictures in another blog post in future.

What about the gold associated with these rocks? Well, I bet that if you analyzed the rocks in the above wall they would have elevated gold concentrations compared to typical meta-sedimentary rocks. However, their gold concentrations would not be that elevated. The gold grades in these Mount Coot-tha rocks are known to be low and patchy — that’s why gold mining was intermittent and relatively small-scale on the mountain. And that’s why the rocks are sold as building stones and road aggregate — they have value there, even if they’re not worth processing for gold.

Gold Mine Hike at Mount Coot-tha, Brisbane, Australia

An old gold mining shaft at Mount Coot-tha.

Considering the COVID-19 travel restrictions at the moment, my ability to go on georneys (geological journeys) is very limited at the moment. However, here in Australia we are fortunate that we can still go outside for some recreation, as long as we stay close to home. We live close to Mount Coot-tha, a mountain with a beautiful forest reserve and botanic garden. Most weekends, I go for a hike with my husband and son on Mount Coot-tha. My son is 2 1/2, so we go on short hikes that are somewhere between 2 km and 5 km in total distance. Fortunately, there are plenty of great easy, short hiking trails at Mount Coot-tha.

One of our favorite hikes at Mount Coot-tha is along the Ghost Hole Track, which takes you past some old gold mine workings. At Mount Coot-tha, there is gold mineralization is located in small quartz-rich lenses that are located in meta-sedimentary rocks, specifically in the Bunya Phyllite and the Neranleigh-Fernvale Beds. The gold mineralization at Mount Coot-tha is not spectacular. However, there was intermittent gold mining on the mountain from the 1890s to the 1950s. Today, no gold prospecting or mining is permitted in the forest, but you can take a walk along an easy hiking trail to see an old gold mining shaft and some remnants of mining infrastructure. You can even have a picnic at the “Gold Mine Picnic Area”.

We really enjoy our little hikes through the former gold mining area. The forest is beautiful, and the remnants of gold mining and associated informational signs are interesting. The hike is perfect if you want an easy, but interesting, hike to go on with a toddler.

Below are some pictures of the hiking trail. Click on any of the pictures below to enlarge them.

Map showing the location of the picnic area and hiking trail.

 

A general informational sign.

 

A view of the trail through beautiful open eucalypt forest.

 

A second informational sign.

 

Remnants of a dam used for processing gold.

 

Another informational sign. Note that “yakka” is Australian slang for “hard work”.  This mining certainly sounds like hard work!

 

Remnants of a wooden bridge used for trams.

 

Another view of the bridge remnants.

 

The last informational sign.

 

An old gold mining shaft.

 

Another view of the trail.

 

The forest is really beautiful at Mount Coot-tha.

 

If you look up, there are sulphur-crested cockatoos in many of the trees.

 

Another cockatoo.

 

You can see some lovely butterflies at Mount Coot-tha at certain times of year. Here’s a Blue Tiger Butterfly.

Admittedly, the gold mining infrastructure is not the most spectacular — there’s not much left. However, with the signs it nevertheless makes for an interesting little hike through a beautiful forest. I highly recommend it for a family hike.

Monday Geology Picture: Gold Train

Posing with the bullion coach at Gold Reef City.

This week I’m sharing a picture of a bullion coach, or a special train that was used to transport gold from the mines in the Johannesburg area to the seaside towns of Durban and Cape Town in South Africa. This particular train is on display at Gold Reef City, a gold mining themed amusement park. You can go and see the train yourself if you visit the park.

Gold theft has long been a problem in the mining industry — and continues to be a problem to this day. Trains such as this are not used anymore (at least not here in South Africa), but for many years heavily fortified trains such as this were the primary way that gold was transported. In addition to the special armor, the train had several guards who lived aboard the train.

Look at the thick doors of the train and the special safe used to store the gold:

Posing with the thick doors of the train. These pictures were taken last year when I was 7 months pregnant with my son.

 

The gold safe inside the train.

Book Review: Diamonds, Gold, and War

My thick paperback copy of Diamonds, Gold, and War.
My thick paperback copy of Diamonds, Gold, and War.

Earlier this week I shared a picture of a few books on diamonds that are on my current reading list. I’ve also mentioned in a couple of previous posts that I’d like to share with you a little information about some of the geology-themed books that I’ve read recently.

Today I’ll be blogging about the first book, which is titled Diamonds, Gold, and War: The British, the Boers, and the Making of South Africa. The book was published in 2007 and was written by Martin Meredith, a journalist, biographer, and historian who has also written several other non-fiction books about Africa, such as Mugabe: Power, Plunder, and the Struggle for Zimbabwe’s Future and The Fate of Africa: From the Hopes of Freedom to the Heart of Despair. Meredith has also written an intriguing looking book titled Born in Africa: The Quest for the Origins of Human Life that I’ve just added to my reading list – so perhaps I’ll review that book later in the year!

I read Diamonds, Gold, and War (hereafter abbreviated as DGW) over a couple months last year. The book is thick, so it took me a few airplane trips and many nights at home to read through. Although it took me awhile to read, without a doubt DGW is the most interesting and important book that I read last year. The book provides a detailed account of key events in South African history focusing on the 1870s to the 1910s. During this time period, rich deposits of diamonds and gold were discovered and developed into mines, kicking off the modern economic development of the region and a legacy of mining that continues to be important to the South African economy to this day. Some of the mineral deposits that were first discovered in South Africa over a hundred years ago are still being mined in today. Several large mining companies, such as De Beers, were founded in South Africa during this time period. However, while the rich mineral deposits played an important role in the economic development of the country, they also led to a fierce battle to control the new-found riches. At the turn of the century, the British battled the Afrikaner Boers for control of southern Africa, waging a costly and bloody war that badly affected both parties. In addition, businessmen such as Cecil Rhodes schemed to dominate the mining industry, ruthlessly forcing aside the competition. During this time period, South Africa’s mineral wealth was largely controlled by a few individuals, who often exploited their mine workers and who did not put much emphasis on health and safety standards, considering mine injuries and deaths to simply be part of the cost of doing business.

Here’s an excerpt from the book’s introduction:

“… in 1871, prospectors exploring a remote area of sun-scorched scrubland in Griqualand, just outside the Cape’s borders, discovered the world’s richest deposits of diamonds. Britain promptly snatched the territory from the Orange Free State. Fifteen years later, an itinerant English digger, George Harrison, stumbled across the rocky outcrop of a gold-bearing reef on a ridge named by Transvaal farmers as the Witwatersrand. Beneath the reef lay the richest deposits of gold ever discovered. The gold strike transformed the Transvaal from an impoverished rural republic into a glittering prize.

What followed was a titanic struggle fought by the British to gain supremacy throughout southern Africa and by the Boers to preserve the independence of their republics. It culminated in the costliest, bloodiest and most humiliating war that Britain had waged in nearly a century…

Two men personified the struggle: Cecil Rhodes and Paul Kruger. Rhodes, the son of an English country parson, used his huge fortunes from diamonds and gold to promote the expansion of the British empire as well as his own business interests… Paul Kruger, the Boer leader and landowner, whose only education was the Bible and who believed the earth was flat, defied Britain’s prime ministers and generals for nearly a quarter of a century.”

DGW covers a fascinating and important time period in South Africa’s history. The book is thoroughly researched and contains several pages of historical pictures and maps. Although the book is long (570 pages) and a little cumbersome at times, overall it is extremely readable – it’s not dry history at all. The book is full of rich detail and anecdotes. In particular, Meredith paints a vivid picture of Cecil Rhodes and Paul Kruger, two of the most influential – and also the most controversial – figures of the time period. Meredith also paints a vivid picture of the early days in the mining towns of Kimberly (diamonds) and Johannesburg (gold).

Personally, the book was an important one for me to read. I’ve been living in South Africa for nearly five years. During this time period, I’ve worked as a geologist in both the diamond and gold industries. Fortunately, the mining industry in South Africa looks quite different today than it did back in the late 1800s and early 1900s. Today, mining companies are much more socially responsible, and there is also a great emphasis placed on the health and safety of employees. The modern South African mining industry isn’t perfect, but it has come a long, long way. I found it extremely valuable to read DGW in order to better understand the origins and complex development of South African’s mining industry. In addition, I found it fascinating to read about how deposits of diamonds and gold were first discovered and developed in South Africa. Fortunately, Meredith’s descriptions of geology are fairly accurate, as history books go! I didn’t spot any glaring geological errors or omissions.

Overall, I highly recommend reading DGW. The book provides a wonderful example of how geology influences history. The discovery of rich mineral deposits in South Africa played a key role in shaping the country’s history and continues to shape the country to this day. If neither diamonds nor gold were discovered in South Africa, the country’s development would likely have taken a radically different path, for better or for worse.

Accretionary Wedge #58: Signpost Outside of Nome, Alaska

Signs there may be gold in the area.
Signs there may be gold in the area.

I’m currently in Nome, Alaska for another season of fieldwork. So, if I’m a bit scarce around here over the next several weeks, that’s why. However, I hope to share a few pictures from Alaska now and then. Here’s one to start things off. While driving around the Nome area today, I ran across this fun signpost. I think that it is a perfect entry for Accretionary Wedge #58! Don’t forget to participate in this month’s wedge if you haven’t already.

Monday Geology Picture(s): Gold Vending Machine, Dubai

A gold vending machine in Dubai.

This week I’m continuing with sharing some pictures from my January 2012 trip to visit my friend Karima in Abu Dhabi, United Arab Emirates. One day we drove over to Dubai for some sightseeing. We drove around, did some shopping, and visited the Burj Khalifa, the world’s tallest building. When we were at the Burj Khalifa, I noticed a strange vending machine: one that sells gold! Specifically, the vending machine sells small souvenir gold bars with a picture of the Burj Khalifa on them. Those are some expensive souvenirs! I’m afraid I couldn’t afford one… although I did try out the golden dessert at the Emirates Palace Hotel in Abu Dhabi.

Golden souvenirs for sale in the vending machine.
A family checks out the gold vending machine.

Monday Geology Picture(s): Golden Dessert at the Emirates Palace Hotel, Abu Dhabi

Our gold leaf decorated chocolate dessert.

For this week’s “Monday Geology Picture” post, I’m continuing with sharing some pictures from my trip to the United Arab Emirates in January 2012. I’ve already shared some pictures of kayaking in Abu Dhabi and of the stunning decorative stones of the Sheikh Zayed Grand Mosque.

One day while I was in Abu Dhabi, my friend Karima and I went to the impressive and opulent Emirates Palace Hotel. According to Wikipedia, this elaborate hotel cost 3.9 BILLION British Pounds to build, making it the second most expensive hotel ever built. The most expensive hotel ever built is apparently the Marina Bay Sands in Singapore. One of the reasons that the Emirates Palace Hotel was so expensive to build is the fact that it is covered in stunning (and likely quite expensive!) decorative building stones. The stonework isn’t as elaborate as the Sheikh Zayed Grand Mosque, but there is certainly much gorgeous stonework at the hotel.

Karima and I didn’t stay at the hotel– we couldn’t afford it, most likely! Rather, we went for a fancy lunch, which was fairly expensive but a fun treat for a girls’ day out. We started with a mixture of savory snacks: Western style tea sandwiches and Middle Eastern style pita bread, hummus, and falafel. Then, we ordered a chocolate treat to share. To our delight and amazement, the chocolate treat was sprinkled with gold leaf.

The gold leaf was very pretty on the dessert. However, if you think about it, eating gold leaf is absurd: it’s very expensive, and it has no taste. Eating gold (at least the purified gold used for food items) won’t hurt you, but it doesn’t have any nutritional value. Nevertheless, considering that we were enjoying lunch at the world’s second most expensive hotel, eating a gold leaf decorated chocolate dessert seemed appropriate. Although the gold leaf didn’t contribute to the flavor, the dessert tasted heavenly; it was one of the best desserts I’ve ever eaten. Kudos to the bakers and chefs.

After lunch, Karima and I walked around the parts of the hotel where visitors are allowed. I’ll share some more pictures from the hotel, including many pictures of some of the beautiful decorative stones, in future blog posts.

A wider view of our golden dessert.
Other golden desserts on display.
Karima and I, posing with our golden dessert.

 

Monday Geology Picture(s): Gold Reef City– Some Historical Views

Old mining picture in the Gold Reef City museum. Looks like hard work!

This week I’m sharing the last pictures from my September 2012 visit to Gold Reef City, Gold Reef City, a gold mining themed amusement park in Johannesburg, South Africa. The amusement park is built on the site of an old gold mine, and these pictures provide some insight into what life was like on the mine in days gone by. There is a museum with some pictures and information on what life was like for the miners– it wasn’t always great, by any means. There are also some historical buildings that were used by the mine supervisors and their families. These buildings are filled with historical artifacts. The museum and historical houses weren’t particularly crowded– I guess the rides are much more attractive than the history, which is a shame.

Another picture in the museum.
A recreation of some of the mineworkers' quarters. Doesn't look very comfortable!
My husband Jackie in front of one of the old houses that belonged to the mine managers / bosses.
A sign in front of one of the historical houses.
Another sign in front of another historical house.
Inside one of the houses.
Another view of the room. This bed looks much more comfortable than where the mineworkers slept!
A dining room table. I really like Willow Ware plates such as the ones on the table.
An old classroom.

I hope you’ve enjoyed all the pictures from Gold Reef City. If you ever find yourself in Johannesburg, I definitely recommend a visit to the park.

Here’s the full list of previous posts about Gold Reef City:
The Entrance
Underground Mine Tour

Gold Pouring Demonstration
Panning for Gold
Some Rides
Trains

Stay tuned fore more geology pictures next week!

Monday Geology Picture(s): Gold Reef City– Trains

Exploring one of Gold Reef City's many trains.

I have a few more pictures to share with you from my September 2012 visit to Gold Reef City, a gold mining themed amusement park in Johannesburg, South Africa. Check out some of my previous “Monday Geology Picture” posts for some more pictures from the park.

This week I’m sharing some pictures of trains. One of the things that I like about Gold Reef City is that there are trains (or train-like things? I’m not sure all of these pictures show true trains) throughout the park. The trains fit well with the park’s mining theme– I imagine that there were many trains among the mines of Johannesburg in the past. If anyone is a train buff and knows anything about these trains, please feel free to leave a comment below.

Another view of the little orange train.
I think this maybe isn't a train? Anyone know what it is?
A train... and a peacock! There are peacocks wandering throughout the park. They're lovely. Also, that's a rollercoaster in the background.
My husband Jackie posing next to one of the trains.
Another little train? Or train-like thing?
Another train with peacocks.

I still have a few more pictures to share from Gold Reef City. Over the next couple of weeks, I want to share some pictures from the historical exhibits that will give some insight into what life was like for mine bosses and their workers during early Johannesburg mining days. Life wasn’t too great for many of the workers, but you’ll learn more about that next week. It’s a fascinating history.

Monday Geology Picture(s): Gold Reef City– Some Rides

The start of one of Gold Reef City's many rides.

After passing through the mining themed entrance, enjoying an underground mine tour, watching a gold pouring demonstration, and panning for gold, my husband and I decided to enjoy some of the rides during our visit to Gold Reef City, a mining-themed amusement park in Johannesburg, South Africa. We visited the theme park back in September 2012.

The first ride that we went on was some sort of crazy rollercoaster where they lift you up and then drop you very fast. It’s one of the scariest rides in the park, apparently. I wasn’t too impressed with my husband as I thought we were just going on a normal rollercoaster. After I recovered from the scary ride, we did go on a couple of the easier rollercoasters and also a couple of fun water rides.There are all sorts of fun amusement park rides, and many of them have gold mining themes. There is also a wonderful Ferris Wheel. From the top, you can see large mine tailings that remind you of Johannesburg’s extensive gold mining history.

The scary ride that drops you suddenly. They have made this ride look like an old mine shaft.
Thunder Mountain! Hang on... isn't that also at Disney?
On the Thunder Mountain log ride at Gold Reef City.
A steep part of the log ride.
Another water ride. I like this one. You go down rapids in a giant spinning boat.
One of the rollercoasters!
A view of the Ferris Wheel.
Some main tailings (in the distance) viewed from the top of the Ferris Wheel.
More mine tailings (distance) viewed from the top of the Ferris Wheel.
Downtown Johannesburg viewed from the top of the Ferris Wheel.