Questões de Concurso

  Mining trucks are monstrous machines that guzzle fuel at a scarcely believable rate. Weighing 220 tonnes, they can get through 134 litres of diesel every hour. Little wonder then that mining companies are focusing their attention on these vehicles as the first step to reducing their carbon footprint.

    Anglo American, in collaboration with several partners, is retrofitting a mining haul truck with hydrogen power technology. A first of its kind, the monster mining vehicle is being piloted in Limpopo, South Africa, at the firm’s Mogalakwena platinum mine. Due to be launched early 2022, the truck will be hybrid, with a hydrogen fuel cell providing roughly half of the power and a battery pack the other half.

    Instead of having a tank of diesel that powers the motor, hydrogen enters the fuel cell and mixes with oxygen to create water in a chemical reaction catalysed by platinum, which generates the electricity needed to power the motors that drive the wheels. By rolling out this technology across its global truck fleet, Anglo American says it will be “taking the equivalent of half a million diesel cars ‘off the road”.

    The construction sector, which includes mining, accounted for 39% of energy-related CO2 emissions in 2017, according to Davide Sabbadin, from the European Environmental Bureau. He says the sector will need to reduce its energy consumption by a third if it hopes to be compatible with the Paris Agreement. “While electric-powered vehicles, generally speaking, are less damaging to the environment than internal combustion engines on a life cycle analysis, this does not mean that they are green,” he says. It all hinges on how the hydrogen is produced. Some hydrogen is created using fossil fuels, which of course means there are substantial emissions as a result. “We should refrain from presenting hydrogen as a technological solution to all problems… all forms of hydrogen come at an environmental cost – water use, impacts on nature,” says Mr Sabbadin.

(Jesse Preyser. www.bbc.com, 21.12.2021. Adaptado)

( ) 

  Mining trucks are monstrous machines that guzzle fuel at a scarcely believable rate. Weighing 220 tonnes, they can get through 134 litres of diesel every hour. Little wonder then that mining companies are focusing their attention on these vehicles as the first step to reducing their carbon footprint.

    Anglo American, in collaboration with several partners, is retrofitting a mining haul truck with hydrogen power technology. A first of its kind, the monster mining vehicle is being piloted in Limpopo, South Africa, at the firm’s Mogalakwena platinum mine. Due to be launched early 2022, the truck will be hybrid, with a hydrogen fuel cell providing roughly half of the power and a battery pack the other half.

    Instead of having a tank of diesel that powers the motor, hydrogen enters the fuel cell and mixes with oxygen to create water in a chemical reaction catalysed by platinum, which generates the electricity needed to power the motors that drive the wheels. By rolling out this technology across its global truck fleet, Anglo American says it will be “taking the equivalent of half a million diesel cars ‘off the road”.

    The construction sector, which includes mining, accounted for 39% of energy-related CO2 emissions in 2017, according to Davide Sabbadin, from the European Environmental Bureau. He says the sector will need to reduce its energy consumption by a third if it hopes to be compatible with the Paris Agreement. “While electric-powered vehicles, generally speaking, are less damaging to the environment than internal combustion engines on a life cycle analysis, this does not mean that they are green,” he says. It all hinges on how the hydrogen is produced. Some hydrogen is created using fossil fuels, which of course means there are substantial emissions as a result. “We should refrain from presenting hydrogen as a technological solution to all problems… all forms of hydrogen come at an environmental cost – water use, impacts on nature,” says Mr Sabbadin.

(Jesse Preyser. www.bbc.com, 21.12.2021. Adaptado)

 

   Mining trucks are monstrous machines that guzzle fuel at a scarcely believable rate. Weighing 220 tonnes, they can get through 134 litres of diesel every hour. Little wonder then that mining companies are focusing their attention on these vehicles as the first step to reducing their carbon footprint.

    Anglo American, in collaboration with several partners, is retrofitting a mining haul truck with hydrogen power technology. A first of its kind, the monster mining vehicle is being piloted in Limpopo, South Africa, at the firm’s Mogalakwena platinum mine. Due to be launched early 2022, the truck will be hybrid, with a hydrogen fuel cell providing roughly half of the power and a battery pack the other half.

    Instead of having a tank of diesel that powers the motor, hydrogen enters the fuel cell and mixes with oxygen to create water in a chemical reaction catalysed by platinum, which generates the electricity needed to power the motors that drive the wheels. By rolling out this technology across its global truck fleet, Anglo American says it will be “taking the equivalent of half a million diesel cars ‘off the road”.  

    The construction sector, which includes mining, accounted for 39% of energy-related CO2 emissions in 2017, according to Davide Sabbadin, from the European Environmental Bureau. He says the sector will need to reduce its energy consumption by a third if it hopes to be compatible with the Paris Agreement. “While electric-powered vehicles, generally speaking, are less damaging to the environment than internal combustion engines on a life cycle analysis, this does not mean that they are green,” he says. It all hinges on how the hydrogen is produced. Some hydrogen is created using fossil fuels, which of course means there are substantial emissions as a result. “We should refrain from presenting hydrogen as a technological solution to all problems… all forms of hydrogen come at an environmental cost – water use, impacts on nature,” says Mr Sabbadin.

(Jesse Preyser. www.bbc.com, 21.12.2021. Adaptado)

(1º§)It sits on the "line of contact" - an almost 500km (310 mile) long fissure between Ukrainian government territory and two enclaves that have been held by Russian backed separatists since 2014. Families, communities, and services are divided by this line. The enduring conflict here on the eastern front has already claimed more than 14,000 lives - at least 3,000 of them civilians, according to the United Nations.

(2º§)The self-styled Donetsk People's Republic (DNR) and Luhansk People's Republic (LNR) are recognised by no one - for now, not even the Kremlin - but they are home to about four million people. Larysa is one of them. She was wrapped up against the cold in a bright blue jacket, pink jumper, and matching woolly hat. She preferred not to use her last name.

(3º§)It takes permission and patience to get from Ukrainian government territory to the other side. Larysa knows the drill. "I do this every six months," she said. "I have been for a check-up at a hospital in Dnipro (in central Ukraine) and now I am going home to Donetsk." As she waited for sniffer dogs to check her bag, she wasn't too concerned about the Russian military build-up on Ukraine's borders.

(4º§)"We have been bombed, and we have been through a lot," she said."I don't believe there will be an invasion, or if there is, it won't be a big one. That's my view as someone with intuition. I watch TV and what politicians say. I think all of this is just to keep us on our toes and stop us from getting too relaxed."

(5º§)Perhaps. But Western leaders have long feared that President Vladimir Putin would fake a crisis in the Russian-backed rebel areas - or the appearance of one - to use as an excuse to invade. The seeds were sewn on Friday when rebel leaders announced that women and children would be evacuated over the border to Russia because Ukraine was planning to attack. Ukraine denied that and most civilians in those areas appear to have stayed put.

(6º§)"We, the people, do not want any war to happen. We want to live, love... We want to love everybody and give them a hug," said Larysa, eyes smiling above her mask. With that she boarded a bus to take her through no man's land to a checkpoint on the other side.

(adapted) https://www.bbc.com/news/world-europe-60460003

   There is no doubt that the resources extracted from mining are critical to our way of life. Likely, you’re reading this on your computer, smartphone, or tablet. Mining touches all our lives daily (in addition to metals used in electronics, think about that can of soda you are drinking, or the aggregate used to pave your driveway). The industry works hard to make sure the net impact is positive. 

   However, the waste associated with mining, both past and present, is an unavoidable result of conventional mineral processing. In the future it may be possible to extract metals like copper and gold without crushing and grinding the ore down to fine particle size and adding considerable quantities of liquid, resulting in conventional tailings.

    What are the challenges associated with conventional tailings? Well, it is all about water. Managing seepage from the tailings themselves, monitoring pore water pressure within the tailings dams or designing facilities to safely store or pass flood events. Because such a significant quantity of water is added during mineral processing, “conventional” tailings dams store the tailings as a slurry. Water within the tailing material is either evaporated, migrates as seepage or remains entrained within the tailings impoundment. Removing water prior to disposal through various means is considered “alternative” disposal. Mining low grades of ore has resulted in increased water use per unit of production. In some cases, the availability of water is one of the greatest constraints on mine development.

Internet: <www.stantec.com> (adapted).