Ok Tedi Mining Limited (OTML) today announced the retirement of its Chairman Sir Moi Avei KBE who has successfully led Ok Tedi for more than six and a half years. OTML Managing Director & CEO Mr Musje Werror acknowledged the significant contribution made by Sir Moi during his tenure saying that “under Sir Moi’s leadership the value of the OTML business has nearly tripled while mine life has been extended by 6 years to 2032. The outlook for the Company is very positive with over K20 billion expected to be generated over this period”. He added that “this has been achieved at the same time as the Company has made a step change improvement in safety performance”. 2020 was the first year with no lost time injuries recorded in over 30 years. During that year recordable injury frequency rates fell by 42% and this followed a 27% improvement in the previous year.” In announcing his retirement Sir Moi said, “I wish to thank the shareholders for the support provided to me as Chairman and the faith shown in me and my Board.” In addition to thanking director’s past and present Sir Moi acknowledged MD & CEO Mr Musje Werror, and his predecessor Mr Peter Graham, for their valued contributions leading OTML during his tenure, and thanked the workforce and local community for their efforts and support. Mr Werror said that “on behalf of the management, and the workforce, we are grateful to Sir Moi for his guidance, wisdom and the positive legacy he leaves and especially supporting the elevation of the first national to become Managing Director and CEO of Ok Tedi. He is warmly regarded by all at Ok Tedi, and we wish him well in his retirement”. An announcement on a new Chairman will be made in due course once internal processes are completed.

Photo Credit: Ok Tedi Mining Limited Ok Tedi Mining Limited (OTML) Chairman Sir Moi Avei KBE today announced that the Company has declared an interim dividend of PGK150 million to be paid in September 2021. Sir Moi noted that despite a fire incident at the mine’s processing facility late last year that impacted its January 2021 production, and a two-week suspension of operations in March 2021 due to COVID19, the Company had benefitted from improved second quarter production and strong metal prices. He said, “this has enabled the Board to declare a dividend to the Kumul Minerals (Ok Tedi) Limited, who now owns 67% of Ok Tedi following the recent transfer of shares from the Independent State of Papua New Guinea, and the three landowner entities representing our communities and collectively owning 33% of Company”. He added that OTML continued to maintain a strong balance sheet with no debt, and liquidity remaining within board established guidelines. Sir Moi thanked management and the workforce for their collective efforts to deliver this result during a particularly difficult time. Furthermore, Sir Moi also announced that the OTML Board had approved an updated 2021 strategic business plan which extends Mine Life for a further three years from 2029 to 2032. This follows the three-year extension announced last year. He said, “this extension of mine life reflects the combination of a strengthening long term copper price outlook coupled with detailed strategic planning work undertaken to find mine waste solutions”. This revised mine life will see the Company generate in the order of PGK20 billion in free cashflow over the next 10 years. He also announced that the Board had approved an investment of nearly PGK750 million over the next two years to extend the service life of the aging processing facility.

Photo Credit: K92 Mining The operator of the Kainantu mine in Papua New Guinea's Eastern Highlands, K92 Mining Inc, expects excellent results in the second half of the year. In a press release, Chief Executive Officer John Lewins stated that the second part of quarter two provided good results, with 16,284 ounces/oz (461kg) of gold produced. “We expect the second half of the year to be stronger than the first half, and the fourth quarter to be the strongest for the year,” Lewins said. “The introduction of the Judd vein system into our mine plan in the fourth quarter will provide a boost to operational flexibility by adding another mining front and high-grade ore which are expected to benefit the operation in not just this year but going forward. “On exploration, we are actively reducing our backlog of holes to assay and core log, while also adding more holes from our drill rig fleet with up to 11 rigs operating at the moment. “This is expected to result in an increase in news flow in the second half of the year. “The immediate focus is reducing the backlog at Judd and we expect to report results near term.”   Reference: Pacific Mining Watch (18 August 2021). “K92 Mining Inc expecting strong results in second half of year”.

Newcrest Mining Limited has announced its annual results for Financial Year 2021, a year marked by substantial challenges across all of its operational jurisdictions as a result of COVID-19. Despite the challenging operating climate, Newcrest is happy to announce that its contribution to the PNG economy has remained considerable. In the previous fiscal year, the overall contribution to the government's revenue increased (year ending 30 June). Newcrest paid K80 million in corporation taxes and K203 million in other taxes, including pay and wages tax, production levy, and customs and excise duties. Lihir paid K99.6 million in royalties for the fiscal year ended 30 June 2021. Fortunately, there were no significant COVID-19 operational disruptions at Lihir throughout the reporting period, which was only achievable because of the hard work and devotion of the Lihir team. Craig Jones, Newcrest's Chief Operating Officer in PNG, reaffirmed this during his presentation of the company's annual statistics. “Our workforce has demonstrated great resilience, some of whom were away from home for many months. “Overcoming these challenges would not have been possible without the assistance of the Lihir community and Nimamar Local Level Government, with whom we have worked alongside throughout this period.” While Newcrest was able to continue operations, the steps required to mitigate the pandemic's impact on Newcrest's employees and host communities, as well as to provide a safe working environment, resulted in additional expenditures of K185 million for the previous financial year. This has had an influence on Lihir's All-in Sustaining Costs, which were US$1,370 per ounce. Total gold output at Lihir was 737,082 ounces in FY2021, which was in line with expectations. Lihir is well-positioned for the future, with annual gold production targets of more than 1 million ounces. With a workforce of about 5000 people, including 2200 permanent PNG national workers and 2800 contractors, Newcrest has added economic benefit to PNG in various ways. Lihir wants to purchase locally wherever feasible, and given the size and scope of the company, this translates into a large investment in the PNG economy, with K1.05 billion spent on PNG suppliers in the previous financial year. Infrastructure, equipment, maintenance, and consumables were all covered in this budget.   Reference: Loop (21 August 2021). “Lihir’s Input To Economy Rise”.

The primary driver of new mine exploration and development will be more foreign investors or investments into the country. Tommy Tomscoll, country manager of Ramu Nico Management (MCC), stated that exploration is a high-risk business, and that the PNG government and landowners will not be able to operate and finance upstream mining activities. According to him, because the mining sector is worldwide, legal frameworks, stability agreements, and the operating environment must be stable, robust, and clear. “I urge the industry to formulate a White Policy Paper that would articulate industry thoughts from mining companies operating in the mining sector,” Mr Tomscoll said. “Let us work together in unity and unison. “We are not competitors but partners in a global industry. “Our competitors operate in another mining sector in other countries.” He said the PNG mining sector is the spine of the national economy. “As new mining production increase, so does the dividend and taxes to government treasury and public investment,” he said. “The mines create significant domestic demand for smaller suppliers of goods and services (or MSME) unmatched by any other sector. “The potential growth area for viable MSME also lies in the mineral sector by developing new mines and expanding old mines.” Mineral Resource Authority managing director Jerry Garry also mentioned that exploration is the lifeline of the industry. “From an exploration point of view, we have been averaging between K200-K350 million annually on exploration. “All of you would appreciate and we have repeated that in many fronts that without exploration there would be no mining because exploration is the lifeline of the mining business and that sector needs to be encouraged,” he said. Despite COVID-19, Garry believes that investments in the exploratory industry will continue.   Reference: Tom, Patrick. Post-Courier (17 August 2021). “More Foreign Investors To Drive Exploration, Says Tomscoll”.

The Hidden Valley Mine contributes K633.7 million to the regional and national economies, indicating its importance in the development and growth of the country's economy. Monica Rau, the Harmony Gold PNG exploration's environment, social, and governance manager, revealed this in a PowerPoint presentation at the Chamber of Mines and Petroleum's community affairs and media workshop in Port Moresby. She also stated that Hidden Valley has paid the government K591.5 million in royalties and direct taxes over the last LOM. Hidden Valley, according to the report, has created over 2000 jobs, with 96 per cent of them located in Papua New Guinea. “From financial year FY 2009 to FY 2020, Hidden Valley has spent K4.9 billion on procurement in PNG, including K1.3 billion with local landowners, K 1.8 billion in Morobe Province, and K 1.7 billion on other procurement in PNG.” The mine has supported a variety of community activities through the memorandum of agreement (MoA), the benefit-sharing trust, and discretionary spending in the areas of community infrastructure, education and health support, law and order programs, gender development, integrated development, and donations, as well as assistance given to communities throughout the mine's life cycle. She also addressed the obstacles and solutions on the path to mine closure, stating that the mine has around seven years to run until more extension options are discovered, but landowners and communities are unwilling to discuss mine closure. Hidden Valley is a gold and silver open-pit mine that began operations in 2007 in the Morobe Province. Morobe Consolidated Goldfields Limited (MCG), a wholly-owned subsidiary of Harmony Gold (South Africa), owns and operates the mine.   Reference: Post-Courier (17 August 2021). “”Rau: Hidden Valley Contributes K633.7M To Economy”.

The Tolukuma Gold Mine in the Central Province has a new interested applicant: Lole Mining Limited, a local mining firm. This came after a previous agreement with Tolukuma Corporation Limited fell through owing to COVID-19. Tolukuma Corporation Limited had previously agreed that the investor will spend K50 million on mine rehabilitation and environmental work, with K15 million going to the liquidator to pay outstanding obligations. However, this did not go as planned, and in a letter to the Mineral Resources Authority, liquidator Andrew Pini notified them that this arrangement is no longer feasible and that a new investor is interested in purchasing a 100% interest in the mine. The liquidator wrote to Mineral Resources Authority managing director Jerry Garry, requesting that MRA evaluate and transfer stake in the license to a new partner, Lole Mining Limited. According to Garry, the new investor is a local mining firm that is listed on the PNG company register and has a partnership with international operators who can manage the mine. According to him, a team from MRA has been charged with reviewing the new structure. “The current mining lease 104 will expire on August 28 2022 however, either the liquidator or the new company if given the ok can apply for an extension based on how their findings of how much and how long they can mine. “The last company did not report to MRA on how much gold reserve the mine currently has because Petromin did not do enough work and report to MRA as expected and that includes resource drilling.” According to Garry, the new investor's plans will be subject to due process, with the Mining Advisory Council making a decision based on the investor's work program.   Reference: Yafoi, Melisha. Post-Courier (10 August 2021). “New Investor For Tolukuma Mine”.

The certification of 24 clans from the Special Mining Lease (SML) regions in Porgera was just completed, according to Mining Minister Johnson Tuke. Tuke stated that all arrangements had come to an end. Barrick Niugini Ltd (BNLinitial )'s lease ended on August 16, 2019. Tuke emphasized the importance of the validation effort in reconfirming the several clans of landowners on the outskirts of the Porgera gold mine in Enga. “Government is determined to reopen the mine. “It has to tick off all the boxes since the first SML has expired,” Tuke said.  Clan agents would then designate their executives to a landowner organization, according to Department of Mineral Policy and Geohazard Management Secretary Harry Kore. Kore emphasized the need of identifying landowners and the state knowing which group to engage with about the project. Jerry Garry, managing director of the Mineral Resources Authority (MRA), highlighted that the mine's landowners have already received compensation. Landowners would receive a part of the royalty and equity under the new Porgera contract, according to Garry. Prime Minister James Marape expressed pleasure with the development of the Porgera Landowners Association's clan agents being confirmed (PLOA). The ratification of the clan agents, he added, was the first step in reorganizing the PLOA, which is a key player in the Mining Development Forum. “The state negotiating team is working hard to meet the required timeframe to ensure that the mine is reopened in September. “Indeed, a mine reopening plan has been discussed by Barrick, the operator of the new joint venture, and while parts of the milestones proposed are slightly delayed, we believe it is still possible to achieve our timetable,” he said. Meanwhile, Marape issued a warning to illicit miners not to enter the Porgera mine.   Reference: The National (6 August 2021). “Validation of special mining leases complete: Minister”.

The Mineral Resource Authority (MRA) is looking for new capital investments of K45 billion for new projects. In his presentation at the PNG Chamber of Mines and Petroleum media and community affairs workshop, MRA managing director Jerry Garry stated that the mining industry alone had generated K17 billion in export income in 2019. “This is the highest export revenue by commodity and is only comparable to PNG LNG.” He stated that the mining industry has been the country's main source of export earnings and will continue to expand. “We are currently looking at new potential capital investments for new projects valuing around K45 billion. “These projects are Frieda River, Wafi Golpu, Woodlark and Geothermal project and others,” he said. “From an exploration point of view, we have been averaging between K200-K350 million annually on exploration. “All of you would appreciate and we have repeated that in many fronts that without exploration there would be no mining because exploration is the lifeline of the mining business and that sector needs to be encouraged,” he said. Despite COVID-19, Garry believes that investments in the exploratory industry will continue. “I am pleased to announce that we have made significant progress in ensuring that benefits sharing flow rightly to the beneficiaries rather than having been parked in integrated holdings, “he said. “This result indicates that the authority is progressing and heading into the right direction from now and into the future.”   Reference: Tom, Patrick. Post-Courier (5 August 2021). “MRA Sets Sights On K45 Billion Projects”.

Photo Credit: Ilya Gridneff/AAP Rio Tinto and Bougainville Copper Limited's attempt to address remaining legacy concerns from the Panguna mine has been appreciated by the Autonomous Bougainville Government (ABG). From 1973 until 1989, President Ishmael Toroama claimed that the Panguna mine was exclusively responsible for funding Papua New Guinea's independence and providing its economic basis. Despite the mine's financial rewards, he added, Rio Tinto and BCL's inability to address environmental harm and local population relocation generated conflict between the people of Bougainville and the corporations, including the national government. “Left unintended these issues became one of the major factors that directly contributed to the 10-year Bougainville civil war,” he said. “In the last 30 years since the mine ceased operations, there is still extensive damage of the environment within the special mining lease and lower tailings (area).” According to Toroama, an environmental evaluation will be conducted to determine the entire extent of the mine's harm. He expressed his government's satisfaction that Rio Tinto and BCL were taking responsibility for their conduct, and he thanked the Human Rights Law Centre for giving legal advice and allowing complainants to submit their complaints to the organization for economic cooperation and development. He also thanked the Australia National Contact Point for helping to facilitate the conversation. The president praised Minister of Education Theonila Matbob for her efforts on behalf of the people in pursuing the subject. “It was through her perseverance that we have been able to reach an amicable solution with Rio Tinto and BCL,” he said. Meanwhile, Toroama put to rest rumours that his administration will give Panguna Mine concessions. “The mine will remain closed until such time as all outstanding issues have been addressed,” he said. “My government’s main agenda is to progress development and prepare our people for independence.”   Reference: The National (29 July 2021). “ABG welcomes miner’s move”.

According to the Porgera Chamber of Commerce and Industry, the State's awareness and validation exercise suggest the mine will reopen later this year. The mine is expected to reopen on September 16, according to Chamber president Nickson Pakea. He said the district and province were anticipating the launch after Prime Minister James Marape met with local stakeholders in Wabag last month. The Porgera valley awareness campaign began on Monday and will conclude on Friday. From July 26 to August 3, there will be a validation exercise. The conclusion of the exercise, according to Mining Minister Johnson Tuke, would allow the appointed agents from the 25 sub-clans to participate in the mining development forum and other sanctioned forums. The proprietors of SML 11's supplementary tenements for lease for mining purposes, mining easements, and mining leases would be involved in the screening process, according to Tuke. Meanwhile, Pakea stated that all community leaders, businesses, and the general public backed the government's legislative exercises allowing beneficiaries to elect their representatives. “People are delighted with Mineral Resources Authority’s tentative programmes and awareness to be carried out this week,” he said. People's sole concern, according to Pakea, was the delay in electing their representatives due to law and order concerns. “Otherwise, it is a good indication and we appeal to the prime minister (Marape) and Barrick CEO (Mark Bristow) to remain focused on opening the mine on the established date,” he added. People, companies, and services in Porgera had been negatively impacted by the shutdown, according to Pakea, and the reopening would help to restore the district's economy and growth.   Reference: The National (22 July 2021). “Chamber: Awareness indicates opening of Porgera mine in Sept”.

According to managing director Jerry Garry, the Mineral Resources Authority is evaluating more than K50 billion in investments in the country. Wafi-Golpu, Frieda River, and Woodlark are among them. “We are also looking at the Central Lime and Cement,” he said. “If that project comes on-stream, it will be one of the first industrial mines ever built in the country.” Garry was speaking at a Port Moresby consultation session on the Mine and Works (Safety and Health) Bill 2021. PNG, he added, was home to some of the world's largest mines. “We have grown from strength to strength,” he said. “If you compare the Bank of PNG statistics, the mining sector alone, in terms of production, has exported over K17 billion in 2020 and 2019. “So it’s a huge industry that we are trying to regulate and manage.” Garry expressed gratitude to the industry for making safety a primary priority. “They have been taking health and safety at the workplaces very seriously,” he said. “We must not only consider (the workers) and the environment but also people living around the (areas) we operate in. “And if we are using any hazards, we must also take responsibility.” The newest mining methods in Wafi-Golpu, known as block cave mining, are one of the new things to expect, according to Garry. “New mining hazards will come with this new mining method,” he said.   Reference: The National (20 July 2021). “Authority assessing investments worth K50bil”.

On June 28, Canadian junior mineral exploration company Freeport Resources Inc. announced it had acquired Carpo Resources Inc. in a definitive share purchase agreement -- and thus took control of the Yandera Copper Project in Madang, within New Guinea’s rich Copper-Gold Belt. Yandera is one of the most prospected resources in PNG that has yet to be mined. Located 95 kilometers southwest of Madang, the project area was the subject of intensive, drill-based exploration programs during the late 1960s and 1970s by a number of companies, including Kennecott Copper and BHP. The historic activity, which included 102 diamond drill holes totaling over 33,000 metres, culminated in the preparation of a mining study by BHP, identifying the Yandera porphyry system as containing one of the largest undeveloped porphyry copper systems (with ancillary molybdenum and gold) in the southwest Pacific. A pre-feasibility study, completed by the Worley Parsons Group in November 2017, indicated Yandera had measured and indicated resources of 727 million tonnes grading 0.39% copper equivalent with inferred resources of 231 million tonnes grading 0.32% copper equivalent. The study also identified 541 million tonnes of probable reserves, grading 0.39% copper equivalent. Since acquiring Yandera, Era Resources Inc. – which is owned by Carpo Resources -- has completed an additional 471 diamond drill holes totaling over 144,000 metres. Era released an updated NI 43-101 compliant resource estimate in December 2016 following a 43-hole diamond drill campaign. “This latest resource is significantly strengthened compared to the 2015 estimate, with a substantial increase in size,” Era says on its website. “It also encompasses an expansion of the footprint, establishment of linkages between previously separate pits and the potential to further optimize pit designs and reduce stripping ratios.” But with Freeport -- which recently acquired Quidum Resources, which in turn controls the Star Mountain project in PNG -- now taking control of Carpo/Era, Yandera seems to be a step closer to development. Freeport confirmed in a press statement that it does not expect to assume any material liabilities, nor will it commit the majority of its working capital or resources to Carpo or the Yandera’s development. “As a result, the transaction does not constitute a fundamental acquisition for the company, within the policies of the TSX Venture Exchange … [and] will not result in the creation of a new insider, or a change of control, of the company.” The acquisition is the second in PNG for the Vancouver-based Freeport in a year. Last October, it purchased the Star Mountains copper and gold project. The closing of the Yandera deal is pending Toronto Stock Exchange approval. PNG Business News was fortunate to interview one man who was involved with Yandera for several years -- Les Emery, who was President and CEO of Marengo Mining Inc. until April 2014. Later that year the company changed its name to Era Resources Inc. “I listed Marengo on the ASX in 2003 and then listed the Company on the TSX in 2008, as Marengo Mining Inc, delisting from the ASX soon after. In 2006 Marengo also listed on the Port Moresby Stock Exchange in Papua New Guinea,” he told PNG Business News. Following the listing of Marengo in November 2003, Emery and his management team started to look for a “company-making asset.” During the next 18 months they reviewed some 150 projects before being offered an opportunity to look at several PNG projects. “Following a visit to PNG in 2005, none of these projects were considered to be what we were looking for either; however, a chance meeting with some people in Port Moresby introduced us to the Yandera Project, which at that time was held in a private PNG company (Belvedere Limited),” he said. Following a review of data on Yandera, produced by BHP and Kennecott Exploration from the pre-1975 period, an agreement was reached with Belvedere’s shareholders for Marengo to acquire Belvedere, making it a wholly-owned subsidiary of Marengo and its PNG operating company (Yandera Mining Company Limited), Emery added. Here is the rest of our Q&A with Les Emery: PNGBN: Please describe the Yandera project. How significant is it compared to existing PNG copper projects? To PNG mining projects in general (existing and prospective)? Emery: The Yandera project is a world class sized copper-molybdenum-gold deposit that will be one of the next phases of mine developments in PNG. As we know, the ‘electrification’ of the world means that the demand for copper is increasing at a rapid rate and many of the world's current mines are seeing their reserves depleted by age, hence new mines are required. These mines are not discovered overnight and as in the case of Yandera, date back many decades to the original discovery, in Yandera’s case more than 50 years. PNGBN: How did Freeport Resources come to purchase Era Resources and thus Yandera? Were you involved in the decision? Will you still be involved with Yandera going forward? Why? Emery: Following my departure from the board of Marengo the company changed its name to Era Resources Inc and during the following year the major shareholder, a private equity company, Sentient, took over the company in full. During 2020, Sentient announced that it had exited its investment in Era Resources by way of a private transaction with an unnamed Canadian group. On 28 June 2021 Freeport Resources Inc, a TSXV company announced that it had entered into an agreement to acquire Era Resource and hence the Yandera Project from Canadian unlisted Carpo Resources Inc for shares. I left Marengo in April 2014, so I had no involvement with the Company from that time.   PNGBN: Has Era's application for the renewal of Exploration Licence 1335 been approved? Why are there questions if it should be granted by the PNG ministry? Emery: From recent enquiries it appears that the current renewal application for extension of Exploration Licence 1335 at Yandera has not yet been approved by the PNG authorities. It is my understanding that this renewal application covers a two year period from November 2019 to November 2021 and the delay in considering this is due to previous work programs/expenditure being considered. In addition, of course COVID restrictions have delayed many administrative matters in PNG. PNGBN: From what you know, has Freeport begun contacting the community at Yandera to get them involved? How important would the project be to the community, and why is it necessary to build a partnership agreement with the local landowners? Emery: As of today (July 3 -- Editor), I have been advised by a number of landowners that no contact has been made by Freeport, or the previous owners of Era Resources. My personal view is that for any company wanting to operate successfully in PNG they need to gain the full trust and support of the community, this can only be gained by giving the community early notice of any activities that affect them, whether not be on-ground activity or corporate matters that affect the ownership of the operator and hence its future activities on site. As with many jurisdictions, in PNG the rights to minerals are controlled by the government, however the land is owned by the traditional landowners, so at all times you need to have full and rank discussions with landowners as to what you wish to do on their land and how it will benefit these people, together with what effect these activities will have on them. Failing to undertake these discussions on a very regular basis will work against any group wishing to explore and ultimately bring a project to mine status. I take pride in the fact that during my time at Yandera we put a big effort in maintaining a very strong relationship with the community at all times, this paying off with total support in return. PNGBN: When would the Yandera project become fully operational? What would it take for Freeport to get it off the ground, in terms of financing, operations, etc.? What sort of revenues could the company expect yearly from this project? Emery: As it has been some years since my involvement with the Yandera project I cannot give a definitive answer, however I believe that with the current demand for copper and with the right group operating the Yandera Project, it could become one of the next major PNG mines by the end of the decade, if not before. Any operating company will however need deep pockets or a substantially-sized partner. PNGBN: Given the government's moves to modify or change the tax regimes for mining, how would it affect Yandera? How far away is the project from getting its license to operate from the government, and what would it take to open it sooner? Emery: The recent moves by the PNG government to see greater participation on mining projects can only assist the Yandera Project, it aligns the aims of all concerned, the company, the government, and the community. PNGBN: How has the COVID pandemic affected mining operations in PNG, and Yandera in particular? What are the opportunities and challenges for the project going forward? Emery: Although I have no direct involvement in any PNG mining operation it has been well reported that some operations have suffered shutdowns due to COVID outbreaks and restrictions. As for Yandera, there has been no effect on exploration or feasibility activities onsite as it has been reported to me that no site activity has been carried out since 2017-2018.

Here is a recent study that investigates the mechanisms of arsenic partitioning into, or out of, streambed sediments downstream of the Porgera Gold Mine in Papua New Guinea. [1] Arsenic (As) is a metalloid element with atomic number 33. Arsenic is known to be released in the environment during gold mining activities. Preventing toxic contamination of soil and water in mine sites is important in a mining operation. This is possible with the application of various techniques on effective arsenic sequestration. A recent study titled “Arsenic sequestration in gold mine wastes under changing pH and experimental rewetting cycles” was done by Beth Hoagland, Luke Mosley, Tess Russo, Jason Kirby, Cecilia Cullen, Matthew S. Fantle, Mark Raven and Joshua Fisher. Their study was featured by Science Digest website last January 2021. Why is this study important in protecting the environment and in assuring health and safety to humans? “The discharge of mine-derived hard rock and liquid tailings waste can alter water and sediment chemistry and release contaminants that pose risks to the functioning of aquatic ecosystems and human health (Nordstrom, 2011; Hudson-Edwards, 2016). Mining companies typically manage these risks by adding lime (Ca(OH)2, CaO) to tailings waste to increase alkalinity and pH and precipitate or co-precipitate metals out of solution. However, such approaches may not be as effective for metalloids (oxyanions), such as arsenic (As), whose response to liming is different than metals such as iron (Fe) (Jones et al., 1997; Smedley and Kinniburgh, 2002). Arsenic, a naturally-occurring metalloid associated with gold-bearing sulfide deposits (Corkhill and Vaughan, 2009; Nordstrom, 2011), is less strongly sorbed to minerals such as Fe-oxides at neutral-alkaline pH compared to metals such as zinc (Zn) and lead (Pb) (Jones et al., 1997). Thus, the efficacy of using lime to remove As from wastewaters is potentially limited as an As remediation strategy and depends on geochemical conditions in addition to pH (Moon et al., 2004; De Andrade et al., 2008; De Klerk et al., 2012)” [1] How do we determine the treatment options for the removal of arsenic from mine wastes? For this, the geochemical conditions of the receiving environment must be considered. “The background conditions of the environment receiving the wastes can influence the aqueous concentration, speciation (e.g. arsenite (As(III)) and arsenate (As(V)), and partitioning of As between water and sediment phases (Smedley and Kinnibrugh, 2002; Cheng et al., 2009). Such conditions include climate, the mineralogy of interacting sediments, and the chemistry of interacting waters (e.g. pH, Eh, and other chemical constituents present in solution).” [1] With regards to the location of the study, its geographic and climatic features, the Porgera catchment is located in the headwaters of the Strickland Watershed in the Enga Province of the Papua New Guinea highlands (5◦27′ 47.83′′S, 143◦ 8′ 45.62′′E). “Mean annual temperature in Porgera is 15.5 ◦C. The long-term mean annual precipitation is 3750 mm and the long-term daily mean precipitation is 10.4 mm, where precipitation events occur more than 300 days per year (Ross, 2012).” With the tropical rainfall that happens almost daily in Porgera, the mine-derived sediments then interact with dilute rainwaters. The kind of rocks present in the highlands are underlain by igneous and sedimentary rocks, which host a suite of sulfide minerals such as pyrite (FeS2), sphalerite ((Zn,Fe)S), and galena (PbS).” These sulfides have submicroscopic gold content, (pyrite and arsenical pyrite). These are extracted using acid-pressure oxidation and recovers using conventional cyanidation techniques (Fleming et al., 1986; King and Knight, 1992). “After extraction, the mine separates the slurry from the gold-bearing solids and neutralizes associated wastewaters and waste sediments with lime (Ca(OH)2, CaO). The treated waste is discharged into the watershed and creates a braided, rocky channel known colloquially as the Red River.” From the initial part of the study, they reported that “arsenic release related to gold mining activity can alter surface water and sediment chemistry. However, the toxicity of As in mine wastes, which is controlled by the speciation, concentration, and bioavailability of As, depends on the geochemical conditions of the impacted environment (e.g., pH, climate, mineralogy, etc).” [1] “This study investigates the mechanisms of As partitioning into, or out of, streambed sediments downstream of the Porgera Gold Mine in Papua New Guinea.” The use of lime as treatment for mine tailings and then discharged directly into the watershed makes the interaction prone to interaction with rain water. This reduces groundwater or acid rock drainage if it were to develop post mine-closure. [1] One of the things to consider about the use of lime in the treatment of the mine tailings is that this practice increases the pH. This in effect triggers the precipitation of some trace metals that were derived from wastewaters. With an overall spike in pH, arsenic can now become more soluble. For the study, the group conducted batch reactor experiments to bring out the effects of changing pH (ranging from 4 to 10) and wetting/drying cycles on arsenic interactions with lime-treated tailings. Another objective of the experiment is to understand the potential arsenic behavior following mine closure. [1] “Across the pH range investigated, lime-treated waste sediments and streambed sediments located downstream of the open pit mine effectively scavenged As from the water column,” according to the study. More specifically, tailings that were treated with lime buffered the pH. This reaction enhanced the interactions between dissolved arsenic and sediment surfaces via surface complexation reactions on amorphous iron oxides, “ as suggested by surface complexation modeling and batch reactor experimental results.” This “arsenic scavenging mechanism” further controlled and counteracted the increased solubility of arsenic at high pH.  Another aspect of the study was conducting a wetting/drying cycle experiments. From this, the group was able to infer that lime-treated tailings that are subjected to repeated wetting/drying cycles rapidly desorbed arsenic during the onset of rewetting, “but sorbed arsenic via an aluminum-bridging mechanism in subsequent wetting/drying cycles.” [1] What useful information can we derive from these results? In general, these results highlight the importance of continued lime treatment in order to lower the arsenic mobility in mine wastes following mine closure. This is applicable particularly for mine sites where wastes are released directly to the watersheds with no containment infrastructure to gather or filter out the outflow. These results highlight the importance of continued lime treatment to reduce As mobility in mine wastes following mine closure, particularly for mine sites where wastes are released directly into watersheds with no containment infrastructure. ----- In conclusion: Gold mine wastes treated with lime facilitated As removal via surface complexation. Lime-treatment enhances As sequestration by mine tailings from pH 4 to 10. Mineral saturation and Al-bridging influence [As] during wetting/drying cycles. ----- Reference: [1] Hoagland, Beth et. al. (January 2021). Science Direct - Applied Geochemistry. Volume 124. "Arsenic sequestration in gold mine wastes under changing pH and experimental rewetting cycles". Retrieved from - https://www.sciencedirect.com/science/article/pii/S088329272030281X Other references: Department of Geosciences, The Pennsylvania State University, University Park, PA, USA Acid Sulfate Soils Centre, The University of Adelaide, Adelaide, SA, Australia Earth and Environmental Systems Institute, The Pennsylvania State University, University Park, PA, USA CSIRO Land and Water, Contaminants and Biotechnology Program, Urrbrae, SA, Australia The Earth Institute, Columbia University, NY, NY, USA About the map Map of stream water and streambed sediment sampling sites in the Porgera Watershed. Shaded areas represent areas of concentrated gold mining activity mapped using Google Earth. Background colors correspond to surface elevation above mean sea level (m) determined from the SRTM 30m digital elevation model. The inset map highlights major watersheds of Papua New Guinea and the location of the Porgera catchment in the greater Strickland River watershed. The Anj-Kai label represents the confluence of the Anjolek and Kaiya Rivers. The Red-Up, Red-Mid, and Red-Pog represent sampling sites at the upstream and mid-stream locations in the treated wastes, and the confluence point of the treated waste stream and Pongema Rivers. Note that Yakatabari Creek, or the open pit runoff site, is a small tributary of Kakai River and the stream reach is not depicted on this map. The Yakatabari Creek sampling location is marked adjacent to Kakai River and upstream of the confluence point of these two reaches.

The Mineral Resources Authority (MRA) is happy with the conclusion of the recent Consultative Meeting in Wabag, as well as the landowners' demands that the Porgera mine be reopened as soon as feasible. The re-opening of the mine, according to MRA Managing Director Jerry Garry, is contingent on the conclusion of various agreements between Kumul Minerals Holdings Limited, the State, and Barrick Niugini Limited (BNL), which are presently being negotiated by the State Negotiation Team. The leaders of the Porgera mining project's 200 to 300 landowners who attended the conference expressed their wish to reopen the mines. According to the MRA, Kumul Minerals Holdings must apply for Registration of the Dealing and legal transfer of interests in Special Mining Lease 11 to BNL and a new project company with Mineral Resources Enga and Landowners at the conclusion of either the Shareholders Agreement or the Commencement Agreement. He added the Mining Minister's mining advisory committee will decide on the transfer to allow the new project business and its shareholders to manage the mine. Furthermore, Garry stated that several legislative criteria for the issuance of SML under the Mining Act 1992, which have been delayed by the Mining (Amendment) Act 2020, must be met concurrently with the commercial talks. MRA has established a set of minimal but important needs, and its staff will be on the ground to guarantee that all relevant consents and agreements are in place before the mine reopens. Garry further noted that the Mining Act of 1992 imposes conditions on the Development Forum that must be met before the Mining Minister requests position papers, attendance, and involvement for the agreement. He said: “Despite the informal acceptance of submission by several stakeholders, everyone will be formally called upon when the minimum requirements are satisfactorily met through the due processes.” In the next months, the Mineral Resources Authority and the State Team will work diligently to ensure that all minimal criteria are satisfied. The team will be implementing programs on-site in the Porgera mine region, and everyone is urged to participate in those activities that will help the mine reopen. “We are aware of the differences among landowners over leadership issues but their consent and support to the government process is required in the best interest of the project and the nation in our endeavour to re-open the mine. “And at the heights of securing a much better deal for landowners, local level government, the provincial government and the State.”    Reference: Loop PNG (14 July 2021). “MRA Calls For Stakeholder Support”.