Cleanout of Coal Mine Settling Ponds using TenCate Geotube® Dewatering Technology
by Philippine Resources - August 31, 2021
Cleanout of Coal Mine Settling Ponds
A large Indonesian mining corporation operating an-open-pit coal mine in a remote part of South Kalimantan, Indonesia, faced a problem on how to dewater silt sediments from settling ponds that had reached their capacity.
As part of the settling ponds cleanout efforts, a TenCate Geotube® dewatering facility was constructed to contain and dewater sediments extracted from the ponds. In total, more than 300 Geotube® dewatering tubes have been used to dewater more than 1,000,000 m3 of slurry containing 170,000 m³ of dry solids annually.
To optimize land space the Geotube® dewatering tubes are stacked up to seven layers high based on standardized units with a circumference of 36.6m and lengths between 17.4m to 61.4m to create large solid landfill structures
The problem facing the mine was how to deal with high volumes of silt in evaporation ponds. The silt, originating from a mix of wastewater from the mines open pits as well as eroded silty rainwater runoff from within the mine catchment area, discharged into the ponds rapidly filling the header ponds before overflowing and clogging adjacent ponds.
Initially, the problem was solved by constructing new ponds until there was a shortage of free land space. Cleaning the ponds required a constant combination of silt dredging and truck relocation in a constant cycle to prevent runoff with high levels of suspended solids (TSS) discharging into and polluting adjacent river channels.
As silt levels in the ponds increased, the cost of dewatering ponds became prohibitive, requiring a more proactive and cost effective permanent Geotube® dewatering solution.
To prove the effectiveness and viability of TenCate Geotube® dewatering tubes, a series of on-site evaluation tests was undertaken. Firstly, a series of Rapid Dewatering Tests (RDT) was conducted to determine the most suitable polymer, the optimum polymer dosage and estimate the final end-of-dewatering solids concentration. Figure 1 and 2 shows the RDT test being undertaken and the effluent and dewatered solids captured.
Secondly, a pilot tube trial was conducted using a few scaled-down Geotube® units that would simulate actual process conditions. The pilot trial validated the results of the RDT evaluation and was used to quantify information and operational implications that was then used in the final project design. Figure 3 shows the pilot trial set-up which utilized a Geotube® GT 500D fabric with a circumference of 13.7m and length of 30.6m.
The pilot trial Geotube® units was laid out over a membrane lined platform to reduce ground infiltration of the effluent. The slurry pumped into the Geotube® units was dosed with polymer at the rate determined earlier by the RDT test. Figure 4 shows the final dewatered cake achieved in the pilot trial Geotube® units.
A Geotube® dewatering facility was constructed to contain and dewater slurry extracted from the ponds. Construction of the dewatering pad started in August 2015.
Prior to placement of the Geotube® dewatering tubes, the surface area of the land was levelled and cleared of sharp objects such as rocks, roots etc as shown in Figure 5a. The pad preparation included the placement of a LDPE liner, drainage trenches, HDPE piping, manifolds and flexible hoses. A working space of about 5m was also allocated between the edge of the tubes and drainage for the operators as shown in Figure 5b.
The first layer of Geotube® GT500D with a circumference of 36.6m and length of 61.4m was installed. Slurry was then pumped into the Geotube® dewatering tubes from a floating dredger in the ponds at a flow rate of 350-500 m³/hour in a 10-hour operation daily. The polymer used was a cationic flocculant injected at a dosage of 1.5 to 3.0 kg/MTds that was into the slurry prior to delivery into the Geotube® dewatering tubes.
The maximum filled height was 2.65m and the final height after consolidation was 1.8m. After the initial Geotube® dewatering tubes have been consolidated, the following layer was then installed (Figure 5c). This process continued until seven layers of Geotube® dewatering tubes was installed. Effluent discharged from the Geotube® dewatering tubes was pumped back into the settling ponds.
The Geotube® dewatering technology installed in this largescaled project has proven to be a highly effective and efficient solution with significant benefits in cost savings and environmental sustainability. The design of stacking seven layers of Geotube® dewatering tubes enabled land space to be well optimized while harnessing the performance of Geotube® technology.
Geotube® dewatering technology improved the water discharge quality by substantially reducing the total suspended solids (TSS) being discharged back into the ponds with its ability of achieving high rates of solids retention and effluent discharge as compared to the previous dewatering methods used.
The solids contained in the Geotube® dewatering tubes also eliminated the risk of rainfall erosion and silt runoff. Presently, the solids in the Geotube® dewatering tubes are being reclaimed as infrastructure earthworks fill, reducing carbon footprint while returning a revenue contribution to the mine operations.
This project has the distinction of being one of the biggest Geotube® dewatering projects ever undertaken in the world providing a wealth of knowledge on the economics of extreme large scale Geotube® dewatering
Philippine Resources - June 30, 2021
Miragrid® GX Geogrid – Segmental Block Retaining Wall application at Davao City Coastal Road
Project Data Project : Davao City Coastal Road Bago-Aplaya Section - Segmental Block Retaining Wall Year of construction : 2017 – on going Client : Department of Public Works and Highways – Region XI. Material : TenCate Miragrid® GX Geogrid Introduction: The Davao City coastal road bypass project will traverse from Roxas Avenue to Bago Aplaya, cutting through NHA Kadayawan Homes, Matina Aplaya, and Bolton Isla. Three roundabouts (or rotundas) will be installed in the 35-kilometer coastal stretch at Roxas Avenue, Times Beach area, and Matina Aplaya. Increasing population and continuous development of the Davao Region leads to the worsening traffic congestion within its major roads. The coastal road project will definitely abate and address the traffic congestion within the city. Problem: The Bago-Aplaya Section facing Davao Gulf going to Talomo is an elevated highway with a 90 degree vertical slope on both sides. The contractor then needs to stabilized and reinforced the embankment effectively. Solution: Segmental block wall reinforced with TenCate Miragrid® GX Geogrid was chosen for the final design of the project for its fast, durable, aesthetics and cost effective construction. Reinforced segmental block wall system consists of precast concrete blocks stocked to form the wall facing, with the soil/sand backfill behind reinforced with Miragrid®GX Geogrid. The blocks are moulded with an interlocking mechanism that allows them to firmly interconnected. The geogrid reinforcement laid horizontally in the soil backfill, is connected to the concrete blocks via the interlocking mechanism at specific design heights of the wall. The construction of the reinforced segment block wall system provides a relatively flexible structure that can tolerate differential settlement without causing distress to the structure.
Philippine Resources - September 24, 2021
DOTr, Pasay City sign deal for monorail, flyover extension
Residents and those working in Pasay City will soon enjoy easier public transportation after the Department of Transportation (DOTr) and the city government signed a deal for the construction of a monorail and extension of the Epifanio Delos Santos Avenue (Edsa)-Tramo flyover. In a live broadcast on Facebook on Wednesday, DOTr Secretary Arthur Tugade and Pasay City Mayor Emi Calixto-Rubiano signed the memorandum of agreement (MOA) for the proposed Integrated Pasay Monorail and Edsa-Tramo flyover extension project. Tugade said the project will be interoperable with the Light Rail Transit Line 1 (LRT-1), Metro Rail Transit Line 3 (MRT-3), the Edsa Busway, and the Edsa Greenways. “[Ito ay] makapagbibigay ng mas mabilis at episyenteng biyahe sa mga pasahero. Magiging mas madali na rin ang access patungong central business district (CBD) ng Pasay (This will provide fast and efficient travel to passengers. Access to Pasay CBD will also be easier),” Tugade said. Aside from its benefits to commuters, he said the project will also create jobs. “Ang paulit-ulit kong sinasabi na karugtong ng mga proyekto para sa kaunlaran ay trabaho para sa Pilipino (What I have always been saying is that development projects go hand-in-hand with jobs for Filipinos),” Tugade said. He said the project is a partnership between the DOTr, Pasay City government, and SM Prime Holdings. “Makakaasa 'ho kayong magpapatuloy ang DOTr sa pagsusulong ng mga proyekto para sa ikauunlad ng pampublikong transportasyon sa bansa (You can be rest assured that the DOTr will continue to promote projects for the development of public transportation in the country),” Tugade said. The MOA signing was witnessed by Pasay City Vice Mayor Noel del Rosario, DOTr Undersecretary for Finance Giovanni Lopez, Undersecretary for Legal Affairs Reinier Paul Yebra, Undersecretary for Railways Timothy John Batan, SM Prime Holdings President Jeffrey Lim, and other representatives from the Pasay City government and the private sector. On Sept. 7, the Pasay City government and the SM Prime Holdings made a joint presentation on the project to the DOTr. By Raymond Carl Dela Cruz Article courtesy of the Philippine News Agency
Philippine Resources - September 24, 2021
DOTr eyes GenSan airport as alternate int'l gateway
Photo credit: Department of Transportation The Department of Transportation (DOTr) is pushing for the inclusion of the newly rehabilitated and expanded airport here as among the alternate gateways for returning Overseas Filipino Workers (OFWs) and international travelers. DOTr Secretary Arthur Tugade proposed the move on Thursday as he personally led the formal unveiling and inauguration of the city airport’s new passenger terminal building and other completed facilities. He said the city’s international standard airport can accommodate airline passengers coming in from as far as the Middle East. Tugade said it can be realized once the proposed increase in the daily cap for returning OFWs, currently at 2,000 for the Ninoy Aquino International Airport (NAIA), is approved. Once the cap is expanded, he said NAIA might “choke” with the influx of airline passengers from various countries. “If we will increase the cap, we need to expand our gateways and not limit them to Clark, Cebu, and NAIA. We can include GenSan among the gateways for travelers from Doha who are going to Manila,” he said in a press conference. He said they will propose such strategy with the airlines serving the international routes, including the Philippine Airlines, and seek the approval of the city government. The other possible alternate gateways could be the Laoag International Airport in Ilocos Norte and the Bohol-Panglao International Airport, Tugade said. The rehabilitated and expanded General Santos Airport passenger terminal building, which was completed early this month, is part of the PHP959-million upgrade implemented by the national government. The other completed components are the procurement and installation of navigational aids and the construction of the new Civil Aviation Authority of the Philippines (CAAP) administration building at the airport. Under the project, Tugade said the passenger terminal area has tripled in size from 4,000 to 12,000 square meters. “This will allow the airport to accommodate more passengers and provide them comfortable and convenient travel,” he said in his speech. A DOTr report said the larger passenger terminal building can now accommodate around 2 million passengers annually, a significant jump from the previous 800,000 per year. Tugade said the improvement at the city airport will continue next year with the upgrading of its air control tower, which he considered as “too low.” He said they will build a “higher and modernized” tower in 2022 to make it “more world-class” and can easily adjust to the needs of the airport. The official said the upgrading of the airport, which started in 2018, is among the agency and the national government’s top priorities in Mindanao. He said the initiative is part of the government’s efforts to bring more progress and economic opportunities in Mindanao, which “suffered from long years of neglect in terms of development.” Tugade said they endeavored to implement these projects despite the challenges posed by the continuing coronavirus disease 2019 (Covid-19) pandemic to pursue their goal of giving a “comfortable and convenient life” to Filipinos. “After the pandemic, we want all these developments in place and ready to benefit the people,” he said. In a video message, President Rodrigo Duterte commended the DOTr, the local government, and concerned stakeholders for completing the projects at the city airport amid the Covid-19 pandemic. He said the city has “gone a long way” in terms of the development of its air connectivity and airport facilities. “The rehabilitation and expansion of the airport passenger terminal building, among others, will truly boost General Santos City’s role as an agro-industrial and eco-tourism hub,” the President said. City Mayor Ronnel Rivera lauded the national government for helping the city realize its dream of having an international-standard airport. Aside from the expanded passenger terminal building, the airport is now capable of accommodating bigger aircraft like Boeing 737 and 747, as well as Airbus A330, A340, and A350. “(What) we are seeing now is a result of multisectoral commitment and dedication in various stages of the airport development, which includes coordination of several initiatives, preparation of the airport master plan, operations, and marketing,” he said. The mayor said the local government will continue to engage with prospective investors and airlines for the opening of more flights to and from the airport and the development of adjacent areas. He cited the proposed establishment of an aerotropolis or growth area centered on the city airport and its surrounding areas. “We are opening a wide array of opportunities, not only on the improvement of our infrastructure facilities but also in terms of investments that will generate more economic opportunities for the city and the entire region (Soccsksargen),” he said. Aside from the inauguration of the airport projects, Tugade also led the unveiling of completed initiatives at the Makar port here. The DOTr said it includes the construction of the Port Operations Building and other vital facilities, which includes a parking area, covered court, port manager’s quarter or Day Care Center, and drainage system. “The improved port of Makar will now offer safer, comfortable, and a more convenient port experience to passengers, while ensuring a faster turnaround for vessels, cargo trucks, and other ancillary service providers,” it said. Article courtesy of the Philippine News Agency
Philippine Resources - September 22, 2021
Cebu-Cordova Link Expressway 83% Complete
Photo credit: Cebu-Cordova Link Expressway As of August 31, 2021, the construction progress of the Cebu-Cordova Link Expressway (CCLEX) project was at 83.84 percent. The P30-billion toll bridge, which will be substantially completed by the end of 2021, will use a full electronic toll system when it opens to motorists in the first quarter of 2022 to enable faster traffic flow and seamless travel. The project recently marked a milestone with the completion of the installation of all 56 stay cables that hold the main bridge deck. On September 11, the Cebu Cordova Link Expressway Corporation (CCLEC), through its contractor, installed the last and longest stay cable, which is 219 meters long. The gap on the main bridge, on the other hand, is now down to only two meters before span closure and preparations are underway for the lowering of the form travelers. These form travelers, which weigh 500 tons in each tower, were used to construct the main bridge’s pier table and deck. Also, all 434 NU (Nebraska University) girders for the entire project have already been installed. With this, the mobile launching gantry used to install the girders have been demobilized. At the Cebu South Coastal Road (CSCR) on ramp and off ramp sections of CCLEX, construction of its substructures is complete. Ongoing works are now on the installation of precast planks and the concreting of deck slab. Also finished is the 200-meter pedestrian footbridge beside the CSCR with all six prefabricated steel walkways already installed. The footbridge will start near the U-turn slot of the South Road Properties’ welcome tower and will connect to the on-ramp sidewalk of CCLEX. At the Cebu viaduct, the construction of deck slab is ongoing. The Cordova viaduct, on the other hand, is now structurally complete with its substructure already done. Installation of handrails are underway. At the causeway, embankment works continue to progress with the placing of 20 vent pipes, which equalize the flow of seawater along the Cordova Channel, is finished. Also structurally complete are the four low-level bridges along the causeway, which will provide fishermen continued access to their fishing grounds. Aside from these, works are ongoing for the toll plaza and the CCLEX Operations and Maintenance Center. CCLEX, highlighted by its iconic crosses on top of the twin pylons of the cable-stayed main bridge over the Mactan Channel, is Metro Pacific Tollways Corporation’s (MPTC) first toll road project outside Luzon. CCLEX, which will be the third link to Mactan Island from Cordova Municipality to mainland Cebu through Cebu City’s South Road Properties, has a design speed of 80 kilometers per hour (kph) and a navigational clearance or height of 51 meters to allow large vessels to pass underneath the bridge. Not only is CCLEX seen to reduce traffic and make traveling more convenient but also spur trade activities and open greater economic opportunities for Cebu and the rest of the Visayas region. CCLEX is a project of Cebu Cordova Link Expressway Corporation (CCLEC), in partnership with the local government units of Cebu City and Municipality of Cordova. CCLEC is a wholly owned subsidiary of MPTC, the toll road arm of Metro Pacific Investments Corporation (MPIC), a publicly listed infrastructure holding company and a member of the MVP Group of Companies. MPTC is the largest toll road concessionaire and operator in the Philippines, which expansion goals include establishing toll operations in the Visayas, other parts of the Philippines, and in neighboring countries notably Vietnam, and Indonesia. Article courtesy of Cebu-Cordova Link Expressway