MRA embarks to reduce mercury usage

Alluvial miners at work on Bougainville

Cedric Patjole | Loop PNG | March 8, 2020

The Mineral Resources Authority (MRA) recently launched a project to reduce the use of mercury in small scale mining operations.

The Project aims to identify the extent to which mercury is used in the industry and how it is used and by whom, in a bid to mitigate health risks.

On March 6th, the ‘Reducing Mercury Use in Papua New Guinea’s Alluvial and Small-Scale Gold Mining Sector’ Project was launched in Port Moresby, following a workshop with key stakeholders and project partners.

The Alluvial Mining industry is one of the largest small to medium enterprise sectors in PNG that engages thousands of rural small scale miners.

It is also a sector that is great health risks due to the usage of mercury.

“This project is designed to get a better understanding of our alluvial sector general, and more specifically to identify the extent to which mercury is used how it is used and by whom,” said MRA Executive Manager of Regulatory Operations, Roger Gunson.

“In addition, it will track the supply trial and identify the regions where it is used. The data collected relating to the sector will be entered into a database administered as part of MRA’s land-folio tenement system.

“This will be able to better inform on policy development, resourcing, training and sector needs.”

Gunson, said the Alluvial Mining is one of the biggest revenue earners for the country with K550 million recorded in 2019.

He said this is similar to revenue generated by smaller mines such as Simberi Mine. However, the use of mercury in extracting gold poses major health risks to the miners.

“Unfortunately, in many parts of PNG gold is extracted through the use of mercury. This is a danger to the health of miners, their families and communities as well as we have heard from the workshop today.

“Hence, we have a paradox, we want the gold and we want to be able to seek it, but we also have a health risk that sits alongside it,” said Gunson.

The project is funded by the US Department of State and implemented by Artisanal Gold Council (AGC) in conjunction with the MRA.

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PNG Yet To Sign Global Treaty On Mercury

Post Courier | September 7, 2018

PNG is yet to become a signatory to the Minamata Convention on mercury, a global treaty designed to protect human health and environment from the adverse impacts of mercury and its compounds.

The objective of the Minamata initial assessment project is to ratify and implement the convention on mercury, facilitated by use of scientific knowledge and tools by stakeholders in the country.

However, PNG is working to be a party to the convention next year by implementing the development of MIA project.

In a presentation at the alluvial mining convention in August in Lae, Patricia Torea of PNG Conservation and Environment Protection Authority said the articles of the convention cover provisions that relate to the entire-life cycle of mercury.

“This includes control and reductions across a range of products, processes and industries where mercury is used, released or emitted. The convention also addresses the direct mining of mercury, export and import, safe storage and its disposal once as waste,” she said.

The MIA project is currently undertaking an in-depth assessment of the management and monitoring of mercury and mercury compounds to enable the government to identify the needs and requirements of the obligations of the convention.

The MIA progress includes establishment of a national coordination committee; report for the assessment on the institutional capacity and legal framework with regards to use and management of mercury in PNG and development of a national inventory of mercury releases.

The challenges are that information or data on mercury is not readily available; and stakeholder participation is poor with regards to providing data or information on mercury in PNG.

The future activities focuses on development of draft regulations for mercury, identifying opportunities, challenges under the minamata convention and development of an awareness raising strategy.

The project is expected to be completed next year.

With the convention entering into force in 2017, the global supply of mercury will decrease over time.

Named after a city in Japan which lost almost 2000 lives due to mercury (Hg) poisoning in 1950. The convention opened for signatures on October 13, 2013 in Japan. It entered into force on August 16, 2017, held its first conference of the parties last September and by August 10, this year, had 128 signatories and 95 parties.

Mercury puts gold miners at risk of heart attack

Hezron Kising | The National aka The Loggers Times | 28 June 2018

Small-scale gold miners who directly handle mercury while extracting gold have a greater risk of developing heart disease, a study reveals.

Michael Kiapulkalow, a senior environmental science lecturer at University of PNG, said mercury and its compounds were highly toxic and had adverse effects on human health, wildlife and the environment.

He said this during a workshop on chemical and waste management by Conservation and Environment Protection Authority (CEPA).

This was in regard to thousands of artisanal small-scale gold mining activities throughout the country where people were exposed to chemicals that could harm them.

“Mercury is highly toxic, causing damage to the nervous system at even relatively low levels of exposure” Kiapulkalow said.

“In Wau-Bulolo district in Morobe and Misima Island in Milne Bay, hundreds of people have been exposed to mercury and will encounter long-term health problems.

“It is particularly harmful to the development of unborn children if a pregnant women is exposed or involved.

“Mercury usually collects in human and animal bodies and can be concentrated through the food chain, especially in certain types of fish. Women who are breastfeeding or might become pregnant should limit their interaction in and around those small scale gold mining areas, since there is high amount of mercury concentration released into the environment.

“It’s generally anticipated that the artisanal small-scale gold mining sector has more mercury releases into the environment than the large operating mines.”

Kiapulkalow said CEPA had implemented a convention with the national government to address the issue by putting in place the Minamata Convention (MC).

“MC is a global treaty designed to protect human health and the environment from the adverse impacts of mercury and its compounds,” he said.

“PNG was not able to sign the MC and is currently not a party to the MC.

“There is currently a joint National Executive Council submission between Foreign Affairs Department and CEPA for PNG to accede to the MC.

“PNG will look to becoming a party to the Minamata Convention in 2019.

“That will protect human health and environment from the risks posed by unintentional and intentional emissions and releases, unsound use and management of mercury.”

Mercury kit study work for small-scale miners

Alluvial miners at work on Bougainville

ONE PNG  | 15 January 2018

A recent mercury research study conducted at the small scale mining branch in Wau, Morobe Province is a collaborative work between the mining engineering department of Papua New Guinea’s University of Technology, the Mineral Resources Authority (MRA) through its small scale mining branch and the University of Kyoto-Japan through the leadership of Professor Takaiku Yamamoto, has released its findings.

The use of mercury has become very popular among artisanal and small scale miners because amalgamation is known to efficiently extract fine particles of gold from concentrates obtained by panning and sluicing operations. Gold alloys with mercury to form an amalgam from which the gold can subsequently be separated by evaporating the mercury.

The simplicity of the technique, low investment costs and its comparatively high gold recovery rate has made the mercury amalgam method an integral part of the artisanal and small scale gold mining operations.

In Papua New Guinea, most of the gold deposits worked by the artisanal and small scale gold miners are alluvial deposits in which the gold particles are liberated from gangue particles. It is customary to use riffled sluice-boxes to recover the liberated gold particles.

However, some of the gold particles, particularly the fine gold, does not settle in the riffle compartments but flows over to be discarded as tailings. In the hope of trapping these fine gold particles the artisanal miners frequently place some mercury in between the riffle compartments.

Then in recent years some semi-mechanised and mechanised alluvial mining operations used grinding mills or amalgam barrels for amalgamation of concentrates derived from their recovery systems before putting it through the knelson concentrators or shaking tables for cleaning.

Due to shear force between centrifugal force and drag force in knelson concentrators or the stratification action of the shaking tables, mercury is easily dislodged from the gold and is lost to the tailings. This is because the bonding mechanism holding gold and mercury together is weak and doesn’t require much force to sever the gold particles from the mercury, and because of size and density differences, mercury ends up in the tailings and eventually in the river systems.

However, by far the most dangerous practice adopted by the miners is the gold recovery process from the gold mercury amalgams. Gold is recovered by evaporating the mercury from the amalgam over an open fire

This process is commonly known as “cooking.” The mercury vapour, which includes fine globules, is partly inhaled while the remainder is released into the atmosphere, which returns as part of the “mercury cycle.”

Methods introduced to avoid the practice of releasing mercury into the atmosphere and which can reduce the mercury loss to less than 0.1 per cent are available but have not been so popular amongst miners due to the discolouring effect on the gold after distillation in a retort.

This discolouration is caused by the presence of iron and arsenic compounds and results in a lower price being offered by gold buyers for the product.

One such device is the “Mercury Retort” which evaporates the mercury in a closed cycle and recovers it by condensing the vapour with cooling water.

Mercury is toxic and an environmental pollutant which drew world attention in 1953 after it was reported that a large number of people living in the Minamata bay area in Japan developed symptoms of disease which affected their central nervous system after consuming fish.

The fish in the bay were contaminated with methyl-mercury as a result of mercury being released into the bay by the Chisso Corporation, a chemical company operating on the shores of the bay. The mercury poisoning was responsible for a variety of clinical symptoms which included speech impediments, failure of muscular coordination, and contraction of visual fields in the eye, disturbance in smooth eyeball movements, enteral hearing loss and unbalance of body. The disease is now commonly known as the “Minamata Disease.”

The recent study conducted at theMRA small scale mining branch in Wau was a collaborative work between the mining engineering department of Papua New Guinea’s University of Technology, the University of Kyoto-Japan and the small scale miners in Wau/Bulolo was to trial a an Amalgam retorting machine from Kyoto University-Japan.

The objective was to test run the Japanese mercury recovery kit, a prototype amalgam retorting machine for the recovery of mercury and critically assess the overall performance, its efficiency and ease of operation of the device.

The promotion and use of the retorts would be very beneficial in the long term as they are capable of reducing discharge of mercury vapour into the atmosphere and the environment. It can also recover bulk of the mercury for recycling which would be a potential economic gain for the small scale miners and the chances of them being poisoned can be minimized through the establishment of central facilities in alluvial mining active areas which will alleviate the more dangerous practice of ‘cooking” amalgams.

A batch of mercury gold amalgam samples were provided by the miners from around Wau/Bulolo mining areas for over a period of one week to conduct the research activity by retorting them in the furnace at four different temperatures (300-500 OC, 300-600 OC, 300-700 OC ,300-800 OC) and the mercury recovery results observed ,recorded and calculated.

From this activity, it is noted that mercury which was emitted during the process was mostly trapped in the condensers 1 and 2.

The carbon filter indicated zero mercury which concludes that the air released at the vacuum pump has zero mercury vapour.

From the results obtained, the research team concluded after careful assessment of the overall performance and efficiency of the mercury recovery kit that it is an appropriate technology and should be promoted and used in Papua New Guinea’s artisanal and small scale gold mining industry for mercury and recycling recovery.

MRA managing director, Philip Samar, who was instrumental in introducing the technology, said the purpose of this collaboration was to reduce and mitigate the increased use and disposal of mercury into the environment and increase alluvial gold production, resulting in the health of both the environment and people plus improving the wellbeing of ordinary PNG alluvial miners.

The MRA through its small scale mining branch in Wau would like to thank its research partners for the collaborative work undertaken.

This has set a milestone in being proactive in reducing and controlling mercury contamination to the environment and the users in the artisanal and small scale mining industry.