Tag Archives: Alum

Onto the ‘proper’ Alum Cliffs track near Taroona Tasmania

After walking across the Shot Tower carpark I had one last look back to where I had been. The sky was amazing.

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In the trees then and often further again along the track, Kookaburra birds laughed at me many times. Ha Ha Ha Ha!  Ha Ha Ha! Ha Ha Ha Ha Ha.  Their feathers camouflaged perfectly with the shadows from leaves and the colours of tree trunks and branches.  They were impossible to photograph. Ha Ha Ha Ha!  Ha Ha Ha!

A sign seen at 10.08am indicated the start of the Alum Cliffs track.

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Then I began the careful descent on a steep 100 metres or so length of a four wheel drive wide smooth gravel track. Partly eroded. Basic stairs were irregularly constructed on one side of this incline.  Bush either side.  A small wallaby surprised me bouncing through the undergrowth.

At 10.15 am I reached the creek crossing below. Peaceful.  Looking up, an even longer climb on the other side was rather dispiriting. On the trek uphill I stopped and sat for a while to take in the view of dense gum tree foliage. There were smooth gum trunks as far as the eye could see.  No wind. Trickling creek below. Peaceful.   As I walked higher, the Shot Tower came into view bit by bit over the trees.

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It was 10.33am when I reached a picnic table and lookout at the top of the Alum Cliffs.

Passing white crowned toadstools with sharp white gills when open, I walked along a shady path which was quiet except for the occasional birdsong, rustling water in the creek below, or the soft voices of other walkers. I learnt from one of the walkers that the Alum Cliffs track used to follow the edge and in order to cross creek gullies, ropes were installed up and down the cliff to steady yourself during the climbs.  Part of those walks included rock hopping along the shoreline as well.

At 10.45am I reached the turn-off to Taronga Road – I did not want to exit the Cliff walk so I continued on. At 10.53am I reached the junction with the Brickfields Track – another time I will return to this area and walk that track to look at the remains of any social history along the way.

A few minutes afterwards, I felt I was identifying exposed alum rock.  I decided it was the rock which had partly oxidised into a greenish colour in places. Whether or not it is the real deal I cannot say.

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Despite tree roots and rocks intruding on this track, the well-trodden dirt with a slight leaf covering made for very easy walking.  Off to the side of the track walking would not have been quick and easy.

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I loved the colours on gum tree trunks as bark peeled away naturally.

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I loved seeing the signs of insects which once burrowed their way under the tree bark.

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At 11.07am I reached a seat with a viewing platform from where I watched an oil tanker motoring up the Derwent, having passed Gellibrand Point on the eastern shore.

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It was a long way down to the River over the Cliffs.

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Then I walked some way with another walker until I needed to stop and start with notetaking and the clicking of photographs.  I continued down across another creek and stopped when I noticed the clay at the bottom.  My earlier research/posting had indicated a connection between the alum rock and clay.

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The track passed through a tiny wet forest area with green pronged tree ferns.  Back up onto a drier track I reached a picnic table at 11.26am. Nearby, a teepee of tree branches and leaves had been built casually.  Would it be better than no shelter in a rainy storm?  Not too sure how long the ‘tent’ would survive much wind.

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Walking past native flowers; pink heath, lots of yellow tiny daisy like flowers, and a delicate 5 petal lavender blue coloured solitary flower.

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I passed smaller tracks off to the left which ended by hovering over the edge of the Cliff, and some to the right which I imagine found their way back into suburbia or onto the Channel Highway.

A glossy scarlet red spider, black legs with a blue iridescent tail crossed my path.  I have never seen one before and knew nothing until I researched once back home; this was Nicodamidae –Red and Black Spider.  Apparently, ‘toxicity unknown, treat with caution’.  Trust me – I didn’t touch it.  The size was that of a woman’s finger nail.

Not long after chatting with a man and his dog, at 11.40am through the trees I could see bits and pieces of Kingston Beach.  My trek across the Alum Cliffs was almost over.

Alum – what is it?

On my next walk along the Derwent River – Stage 12, I will start by walking 3-4 kilometres along the top of the Alum Cliffs from Hinsby Beach to Kingston. I have seen the cliffs from Hinsby Beach on Stage 11, and they look like ‘normal’ cliffs.

But what is Alum? 

According to http://chemistry.about.com/od/moleculescompounds/f/What-Is-Alum.htm, “Alum is any of the compounds with the empirical formula AB(SO4)2·12H2O” and if I tell you Alum is a specific compound of hydrated potassium aluminium sulfate with the formula KAl(SO 4)₂·12H 2O, your brow may wrinkle.  Are you still in the dark?  Worse – it seems there are a number of alum varieties including:

  • Potassium alum is also known as potash alum or tawas. It is aluminium potassium sulfate. This is the type of alum that you find in the grocery store for pickling and in baking powder. It is also used in leather tanning, as a flocculant in water purification, as an ingredient in aftershave and as a treatment to fireproof textiles.
  • Soda alum, with the formula NaAl(SO4)212H2O, is used in baking powder and as an acidulent in food.
  • Ammonium alum has the formula NH4Al(SO4)212H2O and is used for many of the same purposes as potassium alum and soda alum. Ammonium alum finds applications in tanning, dyeing textiles (acts as a mordant and helps to lock in colours), making textiles flame retardant, in the manufacture of porcelain cements and vegetable glues, in water purification and in some deodorants.
  • Chrome alum or chromium alum has the formula KCr(SO4)212H2O. This deep violet compound is used in tanning and can be added to other alum to grow lavender or purple crystals.
  • Selenate alums occur when selenium takes the place of sulphur, so that instead of a sulfate you get a selenate, (SeO42-). The selenium-containing alums are strong oxidizing agents, so they can be used as antiseptics, among other uses.

Other uses of Alum

Alum has several household and industrial uses.

  • purification of drinking water as a chemical flocculant
  • in styptic pencil to stop bleeding from minor cuts
  • adjuvant in vaccines (chemical that enhances immune response)
  • deodorant “rock”
  • pickling agent to help keep pickles crisp
  • flame retardant
  • the acidic component of some types of baking powder
  • an ingredient in some homemade and commercial modelling clay
  • an ingredient in some depilatory (hair removal) waxes
  • skin whitener
  • ingredient in some brands of toothpaste

Considering this list, and in this day and age of developers raping resources, I am surprised our Alum Cliffs are still standing.

The more I learn the more I am overwhelmed by options.  I wonder what the story is of our Alum Cliffs between Hinsby Beach and Kingston. More research is required.