Clean up of Mine Waste in Papua New Guinea

 The Papua New Guinea's (PNG) Minister for Environment and Protection stated on the daily news paper dated October30, 2020 that an Hong Kong based company would be engaged to clean-up the mine waste in PNG at no cost to PNG government and the mining operators.

The company targets the river deltas where the Ok Tedi Mine and Porgera Mine dispose their mining waste. And the overseas based company is kind enough to clean up the mine waste in PNG.

The Minister may not be aware thinking that it is a good idea to get rid of the mine waste without realizing the value of the contents in it, Or he may be very well knowingly trying to get these assumed valuable residues from OK Tedi and Porgera which could be full of gold and other minerals. The Map interestingly showing the targets are Porgera and Ok Tedi river deltas. The foreign investor is not a non-sense to collect the mine waste from PNG deltas targeting Ok Tedi and Porgera tailings disposal rivers.  The tailings contain gold other gangue minerals which are unable to extract at the processing plants in both Porgera and Ok Tedi Mining.  And because both mines discharger their tailings into the river system, the sediments of these rivers (Strickland and Ok Tedi River) are rich in alluvial gold which can be extracted with improved techniques that can recover gold that are of fine particles.

 

It is good the company is interested in the mine waste disposal area and PNG should welcome the idea as it is an investing opportunity. however,  the company's approach is quite not right and must re-strategize and must make its hidden intention known by way of exploration proposal or Mining Proposal rather than saying they want to clean-up mine waste. They should apply for mineral tenement/leases and do the right thing with the PNG Mining Regulator which is Mineral Resources Authority.  

 

It must not be opposed but allow them to  progress and re-phrase to mine alluvial gold from  mine waste disposal areas rather then clean-up mine waste at the deltas. The deltas are rich in alluvial gold and industrial minerals if not known. It can only be proven with exploration and sampling.

Screen shot of The National News Paper publication..

 

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Analysis of Flood in Mul District that caused 6 lives and Catastrophic destruction to properties

The flooding of Kuma Creek has caused massive destruction to properties and confirmed six fatalities downstream. Kuma Creek is such a small creek which is  a tributary of Gumanch River which joins with other rivers to form the Wagi River in the Western Highlands Province.

It is unbelievable for such a small creek to cause massive destruction to lives of people and properties downstream. According to preliminary report posted on Facebook dated 4th February 2020 by Stanley Kheel Kewa, it reads: 

"Preliminary reports from Mt Hagen confirm massive scale of destruction by the Kuma river a tributary of the Gumanch river in Mul district of Western Highlands Province. Four adults and five children totaling nine casualties as reported deaths now. More investigations are in progress as surrounding communities are assessing and investigating the magnitude of the destruction.

Local tribes in the area are the Nengka, Munjika & Mele tribes. Locals reporting from Hagen say this is one of the worst natural disasters the community has ever experienced since time immemorial. The Kuma & Gumanch rivers originate from the top peak of the highest mountain range in WHP known as the Mt Hagen range from which the current Hagen city got its name.

The Nengka Kuiprungils, Nengka Oiyambs and Munjika Rapgangils live at the edge of the Hagen range with houses and gardens patched along the Gumanch and Kuma tributaries.

Ken Paul is a local from the area and reports he is in Hagen town trying to mobilize disaster office and news personnel into the area for further investigations and reporting.

This is just a preliminary report with photos of the disaster zone downloaded from fb pages."

Locals on site - photo courtesy of Facebook

Photo Courtesy of The National Newspaper

Debris of flood - Photo courtesy of facebook

MarapanaVillage aftermath - photo by National newspaper

Now,

one would wonder with questions in anticipating superstitions without establishing the facts and without even having a curiosity in mind. The possible cause of the flood can be best explained as follows;

There must be couple of landslips

caused by what is believed to be over saturated water-table/reservoir

contain by permeable rocks

at both steep

sides of the wedge walls/hills

of  Kuma Creek which is indicated on the snapshot below. 

Then the slipped materials must have

formed an embankment or base which blocked the upstream and the water built up at the upper end of the embankment which formed a temporary mini dam. 

As the mini dam rose with altitude, the stress build up also increased until it reached a

bursting failure in which debris of embankment together with other slipped materials along the creek's

pathway were all washed away and flooded the banks of Kuma and Gumanch Rivers which caused the catastrophic destruction to properties and fatality of 6 human lives. 

The mass flow of loose materials which blocked the flowing river which resulted in forming a mini dam were not competent or strong enough to withstand the pressure/stress build up at the upper end of the blockage, it then burst out and flooded the downstream at a greater momentum which is possible for massive destruction.

So sad that  many loved ones lost their lives due to the catastrophic disaster caused by this unusual flood.

Expected failed area

Location Failure is Expected

Marapana Village

Ariel view of Kuma,Tagla Kwip and Marapana

Note  that this analysis is based on opinion only and not substantiated with facts. If someone wants to proof with factual information then someone need to take a walk up the Kuma river and look for any trace of landslip. If that is so then that would be the cause of the flooding. 

To prevent properties and lives, build houses on higher grounds and also build flood walls along the river banks where valuable properties are installed. Do make awareness to kids and matured people to evacuate quick if unexpected signals are given before massive destruction happens again.

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Geothermal System Modelling - Basic Model

Geothermal System Modelling

Report Submitted by Group Fuji

Basic Model

1.0       Introduction

The Basic Model  parameters (basicmodel.in) was used to calculate the transient behaviour of the hydrotherm system up to 100,000 years. Team Fuji analysed the calculation results in the numerical model by changing one of the parameters in the initial model and run the simulation using HYDOTHERM. In this case, the team changed the size of the heat source while keeping the other parameters constant in the model. The calculation results were run at 20000,40000,60000,80000 and 100000 years.

The physical modes of each scenario are demonstrated in the following model diagrams (Fig. 1-5) below. Heat Source is shown at the centre at 4km x 4km x 2km for the basic model which is represented in red cubical color. The size of the heat source is decreased by 3km x 3km x 2km and then increased to 6km x 6km x 2km in that order. Two different input file  with the different  sizes in X and Y direction  (heat source dimensions only) were run using  Jupiter post-processor (Hydrotherm program). After the simulation in the series of years mentioned above, temperature and flow variation were used to explain the trends in cooling rate of the heat source and temperature variation with time, corresponding analysis is illustrated in the discussion section.

Fig. 1 Heat source at the deeper layer
 of the model (2km thick) 

  Fig. 2 Section View of the initial
 model

  

Fig. 3 Overview of the initial block model

  Fig. 4 Section view of the block model when heat source decreased to 3km x 3km

    

Fig. 5 Sectional view of the block model when increasing the
 size of the heat source by 6km x 6km

                               

Note: everything else is kept constant except the size of heat source changed for the next two models.

2.0    Discussion

1.1 Heat source

The trend of the cooling equations (below) illustrate the differences in the thickness of the heat sources. Therefore, the larger the areal extent of the heat source is inverse proportional to the cooling rate.  The bigger the heat source, the longer it takes to for it to cool down.

Figure 6: Cooling rate of the heat source

The cooling equations for the model with 3kmx3kmx2km, 4kmx4kmx2km and 6kmx6kmx2km heat sources are shown below:

respectively.

1.2  Rate of cooling of the reservoir

The graph below portrays the cooling rate of the reservoir, approximately 1km above the heat source where the convective heat transfer currents are mostly upwelling.

4kmx4kmx2km heat source

Figure 7: Cooling rate of the reservoir

The reservoir cooling curves in Fig.7 above have near - similar trend except for the model with 6kmx6kmx2km heat source which has a kink upwelling at 40,000 years.

1.3 Interstitial steam and water flow

1.3.1        3kmx3kmx2km heat source model

At 20,000years, the hot water rises from the center of the model and travels upward towards the surface as interstitial water moves slowly to recharge the reservoir. At 40,000 years, the rising hot water together with the conduction heat transfer heats a larger area above the magma thus expanding the reservoir area (region in which hot water rises upward).  From 60,000 to 100,000 years, the model cools to below 200°C and convective currents carrying hot water upward weakens over time.

Figure 8: Simulation of 3km x 3km x 2km heat source after 20000 years.

1.3.2        6kmx6kmx2km heat source model

At 20,000years, we have two convective upflow regions which may form two reservoirs about 1km on either side of the center of the model (approx. 9000m and 11000m from LHS of the model).

At 40,000yrs, the two reservoirs merge into one as the heat source cools with convective currents weakening as the model ages all the way to 100,000years.

Figure 10: Simulation of 6km x 6km x 2km heat source after 40000 years.

3.0     Conclusion

In this study, only the heat source dimensions were varied without any change in other parameters.  The results were then evaluated and discussed using that assumption.

The areal extent of the heat sources directly influences the convective flow of fluids and temperature. However, transient temperature evaluation indicates that the rate of cooling of the heat source is inversely proportional to the size of the heat source. The larger size (6km x 6km x 2km) of the heat source allows for a longer period of high-temperature fluid convection. 

     

Figure 12 : 3X3 Heat source       Figure 11: 6X6 Heat source

Source: Groupwork Hydrotherm Basic Model Assignment Report -

Contributions to Group Fuji:

Islomove Sunnatullo-Rock Engineering, Koskey Philemon Kiprotich- Geothermics, Gilbert Bett Kipngetich-Geothermics, Gutierrez Donaire Kevin Yamil - Geothermics, Haissama Osmanali - Geothermics, Kuri Las - Rock Engineering, Lim Pagna-Economic Geology, Mwangi Samuel Muraguri -Geothermics, Ngethe John-Energy Resources, Omondi Philip Omollo-Geothermics, Samod Yuossouf Hassan - Economic Geology

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Frieda River (SMLA9) Mining Warden Hearing

Frieda River copper and gold project is located at the border of East and West Sepik. The holder of the exploration license EL58 lodged an application  for a Special Mining Lease on 24th june 2016. This date is the date at which the application was registered by the Registrar of Mineral Tenements. This process is pretty much similar to that of land lease process.

As per the process, the Registrar upon registration gives notice to the Chief Mining Warden and other officers for technical appraisal. This triggers the next procedure which is the Warden Hearing Process. the Chief Warden together with the registrar fixes a date and time and venue and notify impacted stakes holders regarding the hearing. This is a public forum for the impacted stake holders where the views of the impacted people are gauged.

As such, the above process were followed and Mining Warden hearing was conducted at several venues. The Application was not only the SML application but some other auxiliary leases as well such as lease for mining purposes (LMP), Mining Lease, Mining Easements (ME). To cater for all these leases, there were several venues fixed for hearing. the impacted communities of the Frieda River Project include but not limited to the following:

* Wabia village

*Ok Isai Air strip

*Kubkain village

*Iniok Village

*Aum 3 Village

*Wemimin 1 & 2

* Hotmine Mission Station

The Views of the people were gauged and report compiled for further deliberation. The views of the people were either supportive or objective. The the job of the mining warden is the record all good or bad comments and compile report and also give his/her view.

The other part of the technical assessment is another process which is dealt with by the technical assessment team.

Chief Mining Warden, Andrew Gunua was  Conducting Mining Warden Hearing at Ok Isai, for the Frieda River SML 9 Application in the West Sepik Province 

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Introduction to Mineral Processing- Questions and Answers

S

1.       Write down the main objective and technological summary of mineral processing on mining industries.

The main objective of mineral processing in mining industries is to separate the gangue minerals from the valuable or target minerals or the desired minerals. The desired or valuable minerals are fixed within the ore. The target minerals are to be liberated from the ore and gangue minerals are disposed of.

The summary of the mineral processing technology is in the following sequence:

·        Rock drill & blasting of Ore

·        Crushing & Grinding (Liberation)

·        Sieving & Classification

·        Separation, Extraction, Concentration

·        Concentrate & Metallurgical Treatment

 

 2.       Describe what kind of technology is important for securing resources (or resource supply), including the reason and your idea.

The crushing and grinding technology is very important in securing resources because without crushing or grinding you cannot go further. Crushing and grinding are the only primary actions for further downstream processing. After crushing and grinding you can look for other alternatives of screening and separation and further downstream processing techniques that suites the recovery of target mineral.

For example, you can’t recover in-situ or ROM gold by leaching if there is no fracture to expose gold surface interaction with cyanide solution.  You cannot proceed with flotation if you have not crushed and ground the materials to expose the surface of mineral particles 

3.       It is required to process a low grade ore in which the primary mineral is chalcopyrite associated pyrite. Suggest a process flowsheet, a reagent scheme and a set of operating conditions that may optimize the recovery of copper while minimizing the recovery of pyrite. Explain the reason that led to your decisions.

Froth Flotation process is best for recovering Chalcopyrite. Both Chalcopyrite and pyrite are in pregnant solution at lower pH value. In order for us to separate Chalcopyrite from pyrite, we need to regulate the pH value in the flotation. This can be done by introducing lime and alkaline reagents into floatation thank so that the pH is increased above 6. The pyrite will then precipitate at pH above 6 and the chalcopyrite floats as bubble which is separated from pyrite.

 4.       What kind of technology development do you think is necessary for the mining and mineral processing, which is expected to become difficult in future?

Describe with your idea.

The development of processing technology would be a challenge to recover very low grade ore which is regarded as waste materials or tailings. It is assume that the tailings at least contain some valuable minerals but are hardly recoverable using the metal recovery techniques. It is normally allowed to pass through as tailings into the tailings dams or discharged into the river or on to the seafloor.

Some researchers have come up with proposals to recover low grade ore with a concept of  near zero waste through bio-leaching processing techniques but it will be a challenge whether such technology will truly help to recover very low grade ore mixed with silts and fine particles of rocks and soil.

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Small Scale Mining in Papua New Guinea (PNG)

Small-scale mining in Papua New Guinea was practiced for more than a century when the first ever gold discovery was done in the Sudest Island in in the Milne Bay Province in 1888. The small-scale mining operation then extended to other neighbouring islands of Missima and Woodlark and further to the other parts of Papua New Guinea.

It is also known that about 100 years ago there were also miners mining on the Yodda and Gira fields in Oro Province and 10 years later at Lakekamu in Gulf Province in 1920s. These discoveries led to the development of major mining operations in Papua new Guinea.

Gold is still actively produced in Bulolo Wau area as well as other areas in PNG today.

The early miners were able to open up the Highlands in the 1930's and located gold at Kainantu, Kuta and Porgera. Others discovered the Sepik areas and found gold at Maprik and Amanab. The early miners also mined at Kupai on Bougainville near the closed Panguna Mine.

Gold remains an integral part of the cash economy in areas where gold has been traditionally mined. The local landowners are testing their own land and finding new gold anomalies throughout PNG.

There are more than 50,000 to 60,000 small scale gold miners working at various alluvial gold districts throughout he country using various mining methods.

The most commonly known basic mining methods are sluicing and panning. The miners sometimes use water pump and other motor powered machines in their operation to either go semi-mechanised or fully mechanised.

Abandoned Trommel at Tuguba River Mine Site in Tamo, East Sepik Province

Mechanized Mining Equipment Parked at an alluvial mine site at Tuguba River, Tamo in the East Sepik Province

Note:
The this article is an extract from a publication by Department of Mining Papua New Guinea,2001.

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