Coal News No. 9
Up until now I’ve called this newsletter Cypress-Happy Valley News. But the big opencast mining area of Stockton is currently generating a lot of media. This centres around Solid Energy’s (SE) gross pollution of creeks and rivers and its plan to mine the Skyline Ridge with its critically endangered population of Powelliphanta land snails. So its now Coal News.
Water pollution - start of a big clean-up?
The pressure of our campaign has led SE to announce spending of $20 million over 3 years to clean up water. It’s to be done in stages, and its clear SE’s aim is to deal with visible pollutants first. These are sands, silts and coal fines. Acid Mine Drainage (AMD) is the biggest problem and the most expensive to fix so it’s on the backburner.
The emphasis of the clean-up is the Mangatini Stream despite St Pats Stream being similarly polluted and of similar size. The difference is that Mangatini Str flows over the once beautiful Mangatini Falls on the Charming Creek Walkway. The water is so polluted that the mist rising from the falls acts as a herbicide. It has killed most of the surrounding rainforest, coating what’s left in a layer of black sludge. A viewing platform below the falls was closed 10 years ago due to the danger of falling limbs from dead trees.
Pollution of the Ngakawau River is getting worse and worse since SE is opening new pits all the time. Also, many older pits remain open to provide the range of coals necessary for the various blends SE markets. On top of this, Stockton has never been planned to control and treat waste water. Rock dumps leach AMD and coal fines because they are not capped. Sediment dams, few as they are, only work when rainfall is light. Moderate to heavy rain turns the pollution tap on. Flow rates are often mind-bogglingly vast, since annual rainfall at Stockton is 7000mm.
The clean-up plan involves a series of new dams with the biggest halfway down the Mangatini Stream. SE has identified their central coal mixing area (ROM Pad) as a major source of coal fines. Ford Ck, which drains the ROM, will get a lamella thickener - a machine that seperates out the fines. Some coal dumps will be roofed as a preventative measure.
The biggest problem I see, apart from AMD, is the wide dispersal of coal fines amongst the many huge rock dumps scattered over the plateau. Stockton coal is unusual in that it weathers to a very fine powder. This mixes readily with water to form an oily liquid. Removing the fines requires chemical treatment of the lamella variety.
Another treatment option that has been shown to work at Stockton, more by accident than design, is to let polluted water percolate through a dam of compacted coarse sand. However, the intense rainfall means such dams readily overflow, so they can only be expected to work in the very headwaters of creeks. Then there’s the problem of what to do with the black sludge when its time to clean them.
Currently it goes in the rock dumps, but my guess is it mobilises with the first decent rain and runs out the bottom to pollute another stream.
Granity Ck Dam - a disaster waiting to happen?
A few years ago SE built a dam on Granity Ck to divert polluted water to the Mangatini catchment. Almost immediately it began to leak, first from a single source at around 5 liters per second. Black with coal fines, it flowed like a thick soup. Over the next year or so, the flow rate increased and the number of sources along the foot of the dam did too. The water retained its AMD pollutants, but had become clear, meaning the fines were being filtered out by the dam. A month ago Debbie Chorley of Ngakawau Riverwatch and I went up with SE’s water-measuring team. The number of leaks had increased to 19 and the flow rate to 55 liters per sec (4.7 million liters per day). This was after an unusually dry period and it was apparent from signs of scouring that the flow rate is much higher after rain. The water was clear, but conductivity of around 1000 confirms very high levels of dissolved metals (earlier testing shows the worst are aluminium and nickel). The pH of 2.7 is the most acid reading I’ve heard of on the coal plateau.
So apart from the disastrous levels of pollution pouring down a creek that SE is not even supposed to pollute, there is the grave risk of a dam failure that would knock out bridges on the mine access road and the state highway below. Worse still, it could destroy a couple of homes at Granity and Drifters Café.
The leaks and possible failure were entirely predictable - an engineers report at the time of construction warned that the coarse sand and rock used to build the dam might not hold water.
Granity Ck dam is only one of many leaking structures at Stockton. All the dams and diversion drains leak because none are properly designed. But, surprise, surprise, SE says the chance of the same thing happening at the proposed Cypress mine is "unlikely". On the basis of previous experience, I’d say it’s a virtual certainty. Yet 3 Hearing Commissioners and one Environment Court judge agree with SE’s experts.
There’s an old saying, "bullshit baffles brains". If the people spouting the bullshit have enough letters after their names, and use enough big words, bullshit can officially become truth. This occurs even when all the evidence is screaming out the opposite.
Getting back to SE’s promise of spending $20m on cleaning the visibles from polluted streams, will it work? Not necessarily. Over the last decade or so, SE has spent millions on dams, drains and settling ponds and most of them don’t work. In the case of the Granity Ck dam, they’ve created a major liability.
Briefs
SE has just employed West Coast Regional Council ceo David Horn as its national consents and environment program manager. He’ll be a great asset to SE, since his particular skill is making sure complaints from NGOs and the public never reach the stage of convictions or stop-work orders. Asked by the Greymouth Star if he thought he’d experience a conflict of interest during his final weeks at council, Horn replied that his conduct will "reflect the requirements of the position". I interpret this to mean he’ll continue to support SE until his last day.
NZ Oil & Gas has named the equity partner who will help fund the Pike River coalfield on the edge of Paparoa National Park. Its India’s largest privately owned coke manufacturer Saurashtra Fuels. The huge demand from India and China for coal is keeping prices high.
Forest & Bird’s appeal against the proposed Cypress opencast mine near Stockton goes to the Court of Appeal in the next few days. Good luck.
