STUDY SITES FOR KARANGAKAHE

There are three study sites suitable for school students:

1 A good site for students to investigate the geology of Karangahake rocks (see page 24).

2 Have a go at measuring water quality here (see page 25).

3 There is a prominent quartz vein here – making it a good location to discuss mining. Looking over the river, students will also be able to see the ‘windows’. to

hall and 2 parking

railway tunnel

Karangahake Reserve main car park and to toilets 2

2 River Survey

1 Karangahake Rocks Study The ‘Windows’ Track Karangahake Walkway (return the way you came) (follows river to Visitor Waitewheta River Centre)

track under development 3 quartz vein in cliff Key: (short tunnel)

= bridge Pumphouse N (no access) = walking track Please note: this map has not been drawn to scale. 2 = State Highway 2

= tunnel 23 IV. SITE 1 KARANGAHAKE ROCKS

Background Information Millions of years ago, molten hot rock formed the volcanoes now known as the Coromandel Ranges. As the rock cooled, it developed cracks and crevices. Super hot water (230o-280oC) containing metallic minerals rose up from the hot rock deep below the mountains. As the water cooled it deposited gold, silver and a range of crystalline minerals including quartz, in these cracks and crevices - forming quartz ‘veins’. It is in these ‘veins’ that gold, silver and other minerals can be found.

Where to go Any accessible stony patch along the Ohinemuri River will give productive rock hounding. The best area for schools is at the confluence of the Ohinemuri and Waitawheta Rivers (over the swing bridge and to your left). Keep conservation in mind and ask students to borrow a small representative collection (no more than six prized specimens) for observation and replacement. Look out for quartz crystals, which can also be found in the Ohinemuri and Waitewheta rivers.

What to do 1. Collect your rock sample – choose smaller, flatter rocks. 2. Put on the safety glasses. 3. Wedge the rock between other rocks to stop rock fragments from flying off. 4. Strike the rock with the rock hammer. 5. Use a 3-D viewer or Waltex magnifier (8x magnification), holding the viewer close to the eye and the rock close to the end. View the rock in sun if possible, so you can see crystals sparkling. 6. Sketch or write down what you see.

What you can expect to see

Andesite and dacite Karangahake rocks are mainly andesite and dacite volcanic rocks, that erupted between 10 – 12 million years ago. They are grey with light coloured flexes through them. When broken, many crystals are seen in the dark grey background. The crystals, if light coloured (white or colourless) will be quartz and feldspar. Darker crystals, probably greenish, will be chlorite or pyroxene. Small shining specks may be pyrites.

The other rocks are the same andecites and dacites but they have been changed by hydrothermal alteration.

Quartz Quartz rocks are easy to identify. They are white, cream or pinkish with the crystals easily seen. An examination with the lens will show the crystal side shapes and pointed ends especially if holes and crevices in the rock are examined. When broken to expose a fresh face the quartz, fledspar and chlorite crystals will give a huge array of colours with good-sized cube crystals of iron pyrites (fool’s gold).

24 V. SITE 2 RIVER SURVEY

Background Information

Water pollution from mining In 1895, the Ohinemuri River was declared a ‘sludge channel’ devoid of all life. From 1895 to 1952 the Victoria Battery, capable of processing 200 tons of ore per day, dumped 11 million tons of waste into the river. The waste consisted predominantly of rock ‘flour’ as well as a wide variety of toxic chemicals. In addition, waste was also added from the Crown, Talisman and Woodstock Batteries.

In its heyday, all town and domestic waste was also dumped into the river, most from specially built platforms.

A highly valued Maori food resource of freshwater fish and eels was completely destroyed. The degradation continued unabated until mining ceased in the 1950s.

Floods, so big that water flowed through the railway tunnel, carried the sludge to the at Paeroa and out to the . Recent exploration in the Firth has found gold and other minerals in the mud at Miranda that can be traced to Karangahake.

With today's environmental protection laws such complete destruction of an ecosystem on such a large-scale would not happen.

Improvements in water quality – the presence of trout Water quality in both the Ohinemuri and Waitawheta Rivers has improved to such an extent that the rainbow and brown trout fishery has become one of the most important to Auckland recreational fishers. In clear water conditions, trout can be spotted all along the walkway, particularly from the bridge over the Ohinemuri River between the Waikino railway station and the Victoria Battery.

Rainbow trout are common and weigh about 1kg. Anglers occasionally catch brown trout weighing up to 5kg. Trout are a ‘valued’ introduced species and are used as indicators of good water quality.

Smaller trout feed mostly on the larvae of freshwater insects such as caddis and mayfly, whereas the larger fish target smaller fish – probably native species of the whitebait family.

25 Water level surveys The Regional Council (Environment Waikato) regularly surveys waterways to ensure water quality is maintained. For example there are permanent rain gauges and water level recorders in the Karangahake area.

Information on accumulated rainfall and river levels can be accessed via the internet. Visit the Environment Waikato websites given below before or after your visit – especially if there has been a significant rainfall event.

Rainfall High rainfall events are www.ew.govt.nz/enviroinfo/riverlevelsandrainfall/rainfallmap exacerbated by rapid This web address takes you to a map of the Waikato. Click on the yellow runoff, due to lack of circle above Waihi for the latest rainfall data for the Waitekauri Catchment forest in the river (which feeds the Ohinemuri River). catchment. River Levels During the early days of www.ew.govt.nz/enviroinfo/riverlevelsandrainfall/riverlevelsmap the Victoria Battery On the map of the Waikato on this page – choose the yellow circle located operation, five acres of between Paeroa and Waihi. This will give you the latest river level readings for forest per day was cut to the Ohinemuri River. feed the kilns used to process the ore. The graph below shows the relationship between rainfall levels and river levels for the Ohinemuri River, Karangahake (28 March to 4 April 2001).

Graph showing rainfall and resultant rise in river levels – Karangahake 2001 Rainfall and resultant rise in river levels - Karangahake 2001

River level rises in response to rainfall. 300 river level 16

14 250

12

200 10

150 8

Rainfall (mm) 6 River Level (m) 100 rainfall 4

50 2

0 0

2 April 6:00am 3 April 9:00am 4 April 3:00am 1 April 3:00am 1 April 9:00pm 2 April 3:00pm 3 April 6:00pm 3 April 12:00am 1 April 12:00pm 30 March 6:00am 31 March 9:00am 28 March 9:00am 29 March 3:00am 29 March 9:00pm 30 March 3:00pm 31 March 6:00pm 28 March 6:00pm 31 March 12:00am 28 March 12:00am 29 March 12:00pm Date / Time

26 Now you’re there – Karangahake Reserve

There is a water sampling kit suitable for schools available from Environment Waikato, Grey Street, Hamilton, Tel: 07-856-7184. Remember to return the kit as soon as possible after you have finished with it so that it can be used by other schools. Record your results on the recording sheet on page 29.

What to do: • Make sure students have a copy of the recording sheet (page 29). Walk to the beach area downstream from the western end of the car park and measure: 1. water temperature, 2. water clarity, and 3. look for 'indicators' of good water quality.

1. Water temperature Use the thermometer provided in the kit. Hold the bottom of the thermometer about 10cm below the water surface for 2 minutes. The reading will be accurate to within two degrees. Check with another person before recording the temperature.

2. Water clarity Follow the instructions in the kit for the water clarity tube and the black disk equipment. Record both disk and tube readings.

3. ‘Indicators’ of Water Quality - River Animals Some insects and snails are water quality indicators. Use the nets to sample several stones, following instructions in the kit. Sort the catch out and record animals found, using the identification chart. Make a special record of any mayflies present as the record sheet suggests. All trout observations should be verified by two other people.

Trout Both rainbow and brown trout live in the river and their presence is an indicator of good water quality. Spotting from the bank, you will not be able to identify the species. Trout are easily spotted when the water is clear and when there is not enough wind to ripple the surface of the water. Any of the bridges are good spotting places as well as sections of the walkway that gives views of smooth running water.

Trout are solitary and large (up to 50 cm long, commonly 30 cm) and cruise slowly upstream. Other fish are smaller (except the odd eel) and may be in a shoal. Bullies will be darting around the rocks on the bottom.

Common bully

27 Mayfly Mayflies (Deleatidium species) are used by biologists as indicators of high quality river water.

Use the nets to catch mayfly nymphs - by placing the net immediately down- stream of a (rugby ball sized) stone. Keeping the stone underwater shake it and wipe off any attached ‘material’, the current will carry the catch into the net. Empty the contents into the observation tray and sort out the mayfly using the diagram as a guide. Do this with several stones - always replace them right side up.

Mayfly nymph While keeping the rock

(Deleatidium species) under the water – wipe

off any ‘material’ attached Hold the net down-stream from a stone to the rock. about the size of a rugby ball.

Direction of water flow.

Catch the loose ‘material’ in your net.

Identify Deleatidium from other mayflies (all of the family have three distinct ‘tails’) by their long spiky tails, not feathered like some other species and with the middle tail often longer than the other two. Compare their abundance with other animals found and rate them as none, rare, few, common, very abundant.

28 RIVER SURVEY RECORD: OHINEMURI

School: ______

Teacher: ______Class / Year: ______

Date: ______Time: ______to ______

1 Temperature = ______oC at ______(time) (see Environment Waikato kit)

2 Water clarity tube: ______metres

Black disc: ______metres (see Environment Waikato kit)

3 Number of trout spotted: ______(see Environment Waikato kit)

4 Sightings of fish other than trout. A nil result is important to note. Comments about these: (see notes in this kit)

______

______

5 Abundance of mayfly nymphs: (see notes in this kit)

T none T rare T few T common T v. abundant

Notes: ______

6 Rainfall in the Waitekauri Catchment over the last 24 hours (mm). (see notes in this kit). ______

7 River levels at time of visit: ______m

Metres rise/fall in last 24 hours: ______m (look this up on the Environment Waikato website)

29 VI. SITE 3 GOLD MINING AND GOLD FROM QUARTZ EXTRACTION

The rocks inside Karangahake Mountain and the gorge area are extremely hard. Miners would find a ‘vein’ of quartz rock that was likely to contain gold by exploring the exposed rock faces on the mountain. A ‘vein’ is an accumulation of minerals, usually in quartz, and may range from 5 to 30 cm across.

They would tunnel into the rock following the vein to create a mine. Because the rock was so hard they had to drill long holes into the ‘face’, into which they placed explosives. The force of the ‘shot’ would shatter the rock so they could use picks and shovels to load rubble onto rail trolleys for transport to the surface.

The miners would know how much explosives to use so as not to harm the rest of the mine. Once the ‘ore’ (gold bearing quartz rock) was on the surface it was transported by horse drawn trolleys along tram rails (or in the case of the Talisman Mine, aerial tram) to the battery for processing.

Diagram showing extent of underground mine tunnels in Mount Karangahake - Karangahake Goldfield in 1913. The entire area Trig Station shown in this diagram is termed the ‘lode’. stopes

The horizontal tunnels are also called drives or adits. They were Shafts were dug vertically (or usually dug on a slight angle to aid on a slight angle) into the drainage and transport of ore. rock:

Diagram: S. Frimmel

Over the many years This cross section gives an idea of the extent of the mining undertaken on Mt the Karangahake Karangahake. This is a two dimensional view, imagine a three dimensional goldfield was worked, model of the same view showing the mine shafts and tunnels. up to 1000 tons of ore was mined and The dark areas show the actual amount of quartz bearing ore removed for processed daily. processing. These areas are called ‘stopes’.

30

Processes involved in recovering gold from ore.

Reproduced with permission from: Moore, P. and Ritchie, N. 1996. Coromandel Gold: A Guide to the Historic Goldfields of . Dunmore Press, Palmerston North.

Back at School and While You’re There

What to do

1. Use the information from the above diagrams and from the signs and display panels to write a description of the processes used to recover gold from ore before and after the introduction of the cyanide process. Information from the Crown Battery will be a source for setting out a clear (mostly in your own words) step by step order from crushing to bullion, but a visit to the Victoria Battery Tramway Society’s facility will be the best information source.

2. Learn the meanings of these words: quartz, cyanide, bullion, smelting, precipitation, miner’s phthisis, zinc.

3. Why was the cyanide treatment process such an important discovery for the Karangahake gold fields?

Restrict your work to the early days of mining in Karangahake and Waikino. However, keep in mind later developments that made the work of extraction more efficient right up until mining activity ceased in the area in 1952.

31 Now you’re there – Karangahake Reserve

What to do From the car park at the Karangahake Reserve, cross over the swing bridge (take note it only takes a maximum of 10 people at a time). Over the bridge there will be a track to your left and a little further a track to the right – go straight ahead. A 10 minute walk up the ‘true’ left bank of the (river banks are named looking down stream) leads to another swing bridge. Go past the bridge and carry on through the short tunnel and look for the quartz vein about 20 metres beyond in the face of the cliff. This vein is the kind of sign that miner's would look for before starting a drive or a mine- shaft.

Some of the mine drives that can be seen on the track and the tunnel show how hard the rock was to mine. The explosion from a dynamite charge packed into holes bored into the rock, loosened it and large crowbars and picks were use to break it out of the working face. It really was ‘hard rock’ mining!

VII. HISTORIC STRUCTURES AND BUILDINGS

Now you’re there – Karangahake Reserve

What to do Stand by any of the display signs with photographs of the gorge when mining was in operation (such as the ones located near the Karangahake Reserve car park). Some photos show the batteries and others the townships. Look at the photos given on pages 34 - 41 in this kit and refer to the map on page 33 - showing the location of the old Karangahake township, the Crown Battery site, Woodstock Battery site and location of pumphouse, and Talisman Battery site.

1. Use the photos and the actual scene before you, to visualise the actual setting as it was in the early 1900s. Describe this to a friend pointing out where things were and let them extend your description or describe other areas.

2. Describe what the sounds would be like, from the batteries, the township and the railway and discuss the differences to the sounds you can hear now.

3. As you investigate the remains of the previously thriving industry and township, list what structures have survived and what have not. Give reasons for this.

4. How can we make sure that what is left remains for future generations to discover and enjoy. Make a list of things to be done to ensure this. Research how iron materials are preserved, engineers will know.

32 5. One activity that archaeologists working in places like Karangahake and Waikino do, is make detailed drawings of what they see. Make your own that you could possibly keep to show your own children.

6. Choose one of the structures you could draw in detail during 1 hour using pencil or crayon on newsprint. A cardboard or clipboard backing support will help. It is important you sign and date your work.

The photos on pages 34 to 41 show pictures of the Karangahake township, the Crown Battery, Woodstock Mine buildings, Woodstock Mine Pumphouse, the old tramline, and workers outside the No.8 Level portal of the Talisman Mine N (see diagram on page 30).

2 Victoria 2 The Crown Battery Battery T Site P Ohinemuri River Railway Tunnel

(walkway goes through here) Waikino Owharoa Falls 2 Visitor Centre Karangahake Walkway

Site of old Karangahake Karangahake township Reserve Woodstock Battery Pukekauri Road car park Talisman Battery Road Walking Track T Toilets

Stream P Parking T he Woodstock Waitawheta River Mine ‘Pumphouse’ Waitawheta Road 0 0.5 1km

33