Aug 22, 2016

The metals inside an Olympic medal for Rio 2016

3 min
Recycled and mercury free medals for the 2016 Rio Olympics (Photo: Rio 2016/Alex Ferro)
With the 2016 Olympics coming to a close, a grand total of 2,488 medals were produced and awarded – 812 of them gold, 812 silver and 864 bronze...

With the 2016 Olympics coming to a close, a grand total of 2,488 medals were produced and awarded – 812 of them gold, 812 silver and 864 bronze.

When the medals were announced, the medals’ design was to celebrate sustainability, with the silver and bronze medals produced using 30 percent recycled materials. The gold medals were produced 100 percent free of mercury.

Mercury is used in artisanal and small-scale gold mining. It is mixed with gold-containing materials, forming a mercury-gold amalgam which is then heated, vaporizing the mercury to obtain the gold

Mercury-free mining techniques are considered safer for both the miners directly as well as local communities.

An Olympic gold medal from Rio 2016 is made up from recycled silver at 92.5 per cent purity.

This percentage of silver purity keeps the Olympic medals within the minimum IOC requirements:

  • Gold medals to be composed of at least .925 grade silver plated with 6 grams of gold
  • Silver medal to be composed of .925 silver
  • Bronze medal to made of mostly copper (40 percent) with tin and zinc – which was made up from melded and decontaminated waste material from the Royal Mint of Brazil

As a result of the mercury free production and recycled material, the value of the gold medal is actually lower than it could have been. It is currently valued at approximately $564, based on the current commodity price of gold ($43.76 per gram) whereas if it was 100 percent gold it’s value would be closer to $22,000.

Three methods of artisanal and small-scale mercury free gold mining:

Spiral Concentrators – Specialised pans tilted on an angle with spiralled grooves in a pan which lead towards the centre where a hole is connected to a container to catch material. The pan is rotated automatically as concentrate is fed into the pan by an operator. Through water being sprayed into the spinning concentrator, lighter particles are washed away while the spiral grooves direct denser particles such as gold into the hole and centre of the concentrator. Following multiple repetitions of this process, high grade and often liberated gold is produced. 

Shaking Tables – Elevated tables with raised ridges running horizontally tilted to one side. Crushed ore or sediment, otherwise known as mineral feed, and water is released onto the table and washes the feed down it. Specialised grooves on either side of the table traps gold while the water washes the lighter minerals away. The tables are shaken through a motor to aid in the separation of gold particles.

Flotation – Flotation is a process often used by large scale mining organisations in which a mixture of crushed ore and water, known as a slurry, as well as frothing agents are added into a flotation machine. Air is then released into the tank of the flotation machine and an agitator creates air bubbles within the tank. Hydrophilic minerals, such as gold, are then brought to the surface of the water through the bubbles and accumulate as froth. This froth is scraped off, creating a concentrate of gold. The flotation method is a successful process of creating a high quality concentrate of gold.




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Jan 30, 2019

Deloitte predicts industry transformation - Tracking the Trends 2019 report

Daniel Brightmore
3 min
Deloitte reveals top ten trends transforming mining in annual Tracking the Trends report
Deloitte has published the eleventh edition of its an...

Deloitte has published the eleventh edition of its annual report on the mining industry. Tracking the Trends identifies the top ten trends transforming the future of mining in 2019

The Deloitte report endeavours to provide the mining industry with insights it can leverage to support its continued quest for productivity, capital discipline, strategic development and sustainable growth.

Philip Hopwood, Deloitte’s Global Leader - Mining & Metals, commented: “It appears that the mining industry is poised for greater growth than it’s seen in a decade, but today’s market realities are very different than those of the past. We’re now dealing with geopolitical tensions in the form of trade wars and tariff concerns, as well as looming asset shortages. Rising commodity prices should fuel expansion, but could also result in a return of inflation and the costs that go with it, eventually eating into margins. 

Disruption and volatility has become the new normal and the pace of change is outpacing our ability to adapt. This makes it imperative for mining companies to clarify how they plan to drive value into the future and how they intend to respond when prices inevitably drop again.” 

Related stories:

EY survey finds losing 'licence to operate' is the biggest risk to the industry in 2019

Predicting the disruptors of tomorrow’s mining industry: Deloitte’s tracking the trends 2018

Renewables the key to energy cost savings and competitive edge says Deloitte

Here are the key messages provided by the 2019 report:

  • Disruption and volatilitymake it imperative for mining companies to clarify how they plan to drive value into the future and how they intend to respond when prices inevitably drop again. To thrive into the future, mining companies will need to challenge the status quo by soliciting a diversity of opinions and taking the risk to do things differently. 


  • Technology and artificial intelligence (AI) will play akey role, not only in helping companies envision future scenarios, but in identifying risks at an enterprise level and transforming the supply chain. Moreover, advances in finance platforms, sensor technology, autonomous vehicles, cloud- based solutions, and analytics are paving the way for the design of a digital mine. 


  • Understanding the needsand perceptions of people both inside and outside the organization will be critical. Companies must build amore diverse workplace and address succession planning, while fostering loyalty and retention among existing employees. At the same time companies must do more outreach to local communities, governments, and consumers so they can be more transparent and receptive. 


Top Ten Trends Transforming the Future of Mining:

  1. Rethinking mining strategy - Embedding the discipline to deliver measurable value across the cycle 
  2. The frontier of analytics and artifcial intelligenceMoving up the maturity curve 
  3. Managing risk in the digital era - Exploring a new approach to controls and risk management 
  4. Digitizing the supply chain - Why innovation requires integration 
  5. Driving sustainable shared social outcomes - Finding value beyond compliance 
  6. Exploring the water-energy nexus - Making the case for a systematic approach 
  7. Decoding capital projects - Learning from past mistakes
  8. Reimagining work, workers, and the workplace - A blueprint for the future 
  9. Operationalising diversity and inclusion programs - From theory to practice 
  10. Demanding provenanceEVs and battery minerals provoke the desire for provenance 

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