Customised liner solution boosts SAG mill throughput and mine profits
by Philippine Resources - March 08, 2022
Photo: The existing grates within the SAG Mill were pegging. Critical size grinding media were blocking apertures, reducing throughput
A gold and copper mine in South East Asia was experiencing a range of challenges with its SAG mill that were hitting productivity. Facing a significant increase in ore hardness that would have exacerbated the problems, the mine turned to us to provide a solution for a safer and more productive grinding operation.
A multifaceted mill challenge
A remote copper and gold mine in South East Asia had a problem: its 34 ft SAG mill was experiencing a range of performance issues that were limiting its production performance:
- Pulp dischargers of many parts. The steel dischargers on the SAG mill comprised 187 pieces. Not unsurprisingly, this led to lengthy downtimes for component replacement. Making the situation worse: the discharger service life was a relatively short 12 months.
- Inadequate liner service life. The SAG mill’s steel liners were failing to meet the required service life. To remedy the problem, the supplier had added more material to the liner design. But this created its own challenges, reducing the effective grinding volume and adding weight to the mill that was pushing bearing pressures dangerously close to limitations.
- Peening liners. The steel used to make the liners produced a significant amount of peening. This made liner removal a time-consuming activity and more hazardous activity, as a heat lance is needed to remove peened liners. It also increases the risk of structurally damaging the mill’s shell.
- Pegging of the grate plates. There was excessive pegging of the grate plates by worn metal grinding media, reducing flow. As temporary measure, the mine was cutting out the pegged media every few weeks. Which only increased the time and cost spent on mill maintenance.
To solve these challenges, the mine issued a request for quote to three companies with the challenge to improve the safety of mill maintenance and increase mill discharge. In practice, this meant reducing the number and length of maintenance interventions, as well the need for hazardous installation manoeuvres, lowering mill weight and eliminating flow constraints, such as clogging and pegging.
The beginning of the solution is understanding the problem
The journey to our solution began with a thorough review of operating conditions and liner design. Through this, we determined the first course of action should be to tackle the problems associated with the discharge system. This would allow us to increase throughput and reduce weight – and would also lead to other objectives being met.
With some key improvements in mind, we created sophisticated DEM simulations to help evaluate what discharge design would best meet the mine’s objectives. These simulations allowed us to beat the mine’s throughput target of 2,100 tpd and forecast a maximum possible throughput of 2,300 tpd. The new simulated design also showed a significant increase in service life, meeting the need to reduce maintenance interventions.
After initial onsite discussions, mine personnel were invited to review the design adjustments and define the final scope. This made sure customer knowledge was also incorporated into the solution, as well as those of our engineering team.’
Our solution centred on our PulpMax™ composite mill liners, which were combined with material and design modifications to the steel lining system to promote increased efficiency and service life. The new liners boast 27% fewer parts (136 vs 187) and 45% lower weight (106,130 kg vs 191,962 kg).
- Made from material that is up to 50% LIGHTER. This makes the liners easier to handle and improves worker safety. Lighter materials allow us to engineer larger components at reduced weight. It also results in less parts.
- They typically have 50% FEWER PARTS. This results in a faster reline speed and quicker installation, and this adds up to workers spending less time in a confined space performing hazardous work.
Along the journey, we were also able to provide solutions to other challenges – for example, pegging of the grates and peening of the discharge steel. The result was a solution that exceeded original expectations:
- Improved safety. Fewer pieces and lower weight make maintenance simpler and quicker. This reduces the amount of time that workers spend on the mill – improving safety. It also lowers the total cost of ownership. Compounding these benefits, PulpMax composite wear liners last much longer than previous liners – through some 25 million tonnes of production. Liner service life has therefore been extended from 12 months to 15 months and based on wear measurements, could extend to 18 months.
- Improved throughput. The new system consistently achieves throughput of 2,250-2,300 tpd, exceeding the target of 2,100 tpd. This results from:
- Reduced liner mass (>100 tonnes)
- Improved shell design
- Improved discharge efficiency
- Less clogging and pegging
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Philippine Resources - June 30, 2021
Gold mine in Indonesia installing KREBS® UMD™ Pumps to increase safety
Article by Rachel Johnson A large gold mine in Indonesia set a goal to increase safety. As part of the goal, they evaluated the frequency and risk of site maintenance procedures to find areas where they could make changes. They found that their mill discharge pumps had shorter periods between maintenance events than planned, and researched further to find that the wet end components were not reaching the target wear life. Every maintenance shutdown carried a low level of risk, but in a facility that processes 240,000 tons of ore per day, the frequent maintenance tasks added up to be significant. Site management decided that the time had come to investigate other pump options. The conditions the pumps were operating under were highly abrasive and severe, but management was hopeful that a safer and longer-lasting solution was possible. Safety would remain the top priority in any pump conversion plan, but if the downtime caused by pump maintenance could safely be reduced, the increase in production would be welcome. The mine reached out to FLSmidth to ask if they had any solutions. FLSmidth responded with a proposal for a side by side comparison between the existing pumps and the KREBS Ultimate Mill Discharge (UMD) pump. For the comparison, FLSmidth would install a UMD pump at the discharge of one ball mill. The remaining mills would continue to operate with the existing pumps. During this same period, FLSmidth would set up a trial of different material combinations for the suction liner and wear ring in the UMD pump to make sure that the final recommendation would minimize maintenance events as much as possible. The gold mine agreed to the proposal and FLSmidth installed a UMD 650×550 mm (26×22 in) pump at the ball mill discharge. The pump fed the highly abrasive discharge to a cyclone but it was designed for severe duty applications such as this. A trial was planned in phases to test different combinations of the suction liner and wear ring, with the materials for the impeller and casing remaining constant. At the same time as these materials were to be tested, all components would be compared with the wear experienced by the remaining discharge pumps. Before starting the first phase of the trial, FLSmidth established targets that the life of the suction liner assembly would be 200% of the competitor pump, the life of the impeller would be 220% and the life of the casing would be 102%. At the end of the first phase of the trial, the UMD pump was stopped to evaluate wear. Even wear was seen across the wear ring, but the suction liner showed little wear and could have been used longer. At this point, the suction liner assembly (which includes the wear ring) had already run 306% of the competitor’s suction liner life and with a new wear ring the suction liner could have lasted significantly longer. Regardless of remaining wear life for the suction liner, it was decommissioned to prepare for the second phase with a new wear ring and suction liner material. After the first phase, the impeller and casing had significant life remaining, as expected. These parts had not reached the end of their wear life for the UMD or competitor pumps. New materials would not be tested in the trial so they were left in the pump to continue the comparison. Component Wear Life (%) Competitor pump 24×20 Target Wear Life (%) UMD 26×22 Run 1 & 2 Wear Life (%) UMD 26×22 Run 1 Wear Life (%) UMD 26×22 Run 2 *Suction Liner Assembly 100% 200% 306% 233% Impeller 100% 220% (still running) **see note 270% (still running) **see note Casing 100% 102% (still running) **see note 90% (still running) **see note * KREBS® suction liner assembly contains the wear ring ** Note that the impeller and casing operated in both Run 1 and 2 and are still running. The current wear life percentages are shown in Run 2. At the end of the second phase of the trial, the UMD pump was stopped again to evaluate wear. Significant uniform wear was seen on the suction liner, but the wear ring showed no signs of wear and could be used longer. The suction liner assembly had run 233% of the competitor’s suction liner life and the wear ring could last longer with a new suction liner. The suction liner assembly was decommissioned to prepare for the third phase with a new wear ring and suction liner material. After the second phase, the impeller and casing still had significant life remaining so they were left in the pump to continue the comparison. At this point, the impeller had already lasted 270% of the life of the competitor’s impeller. The casing had so far lasted 90% of the life of the competitor’s casing, and with the wear seen it was anticipated that it also would reach or surpass the target wear life. Phase three of the trial is ongoing and a fourth phase is planned, so the successes presented here will be surpassed as the best material combination for the UMD wear components is determined. Yet, the existing data shows that the UMD suction liner assembly lasts more than three times the life of the competitor’s liner and the impeller lasts more than 2.7 times the life of the competitor’s impeller. The gold mine is pleased with the results they have already seen from the pump comparison and the added safety that they can expect when the trial is complete and they can proceed with converting the remaining discharge pumps. The added financial benefit of an increase in production due to the decrease in maintenance is also appreciated.
Philippine Resources - August 26, 2021
Advanced froth phase control: the key to higher recovery
Considered a mix of science and art, flotation is the most widely used process for extracting vital minerals in the modern mining operation. As the amount and type of froth changes from cell to cell, the best recovery systems must be able to accommodate variable froth conditions, otherwise valuable materials end up being lost to tailings. Newer technologies eliminate the guesswork previously associated with flotation, and the latest advancements allow for adapting to the unique conditions within each cell. This improves control of the froth phase and directly affects the mine’s ability to recover either higher volumes or higher grades. As a leading innovator in froth recovery, FLSmidth has created a Froth Recovery Upgrade package that provides customers with more control, resulting in better overall metallurgical performance. The package includes four critical technologies: A level sensor with a robust design and no moving parts, which accurately senses the depth and level of slurry within the cell. Actuators that receive data from the level sensor and adjust the dart valve position to maintain slurry levels. Radial froth crowders to reduce top-of-froth surface area and facilitate movement to the nearest radial launder. Froth cameras, which measure the froth’s velocity and stability and can also infer the froth grade. Ideally, a flotation operation would utilise all four technologies to achieve optimal recovery; however, the full package can be segmented and installed as individual components, based on customers’ needs. This flexibility, and the real-world customer results, are illustrated by the examples below. Customer 1 – Level Sensor and Actuator A large copper mine in Peru approached FLSmidth to increase recovery in an 8-cell flotation bank. The mine’s existing equipment for monitoring slurry levels and controlling dart valves lacked consistency, which caused large deviations in level control. The lack of control and stability reduced overall copper recovery and had a significant impact to the bottom line. Left: Multisense Level Sesnor. Right: Festo Actuator160 Every large fluctuation in level control resulted in two scenarios: First, the cell level would become too high, and pulp would overflow into the launders, resulting in unacceptable grade. Then the level would drop too low and result in little to no recovery of the froth phase, impacting overall recovery. Data from the condition monitoring system revealed an opportunity for improvement, as shown in Figure 1. Sporadic movement of the actuator (blue) caused unstable deviations to the slurry level (green), causing it to fall short of the target level (yellow) needed for optimal performance. Actuator Figure 1 FLSmidth engineers recommended installation of new level sensors and FESTO actuators. The customer agreed to replace its current equipment, and the upgrade yielded immediate improvements. Following the retrofit, slurry levels showed significantly higher stability and remained consistent within the target level, shown in Figure 2. Actuator Figure 2 After a month with the new equipment, slurry levels consistently remained on target. As a result, the customer recovered 0.5% to 0.8% more copper than previously possible with the older equipment. Based on the short-term results, the customer anticipated replacing the remaining flotation cells in the entire plant with new level control. The mine’s return on investment was less than three months. Customer 2 – Adjustable Radial Froth Crowders Another copper mine in Peru consulted with the FLSmidth Flotation team to improve its froth phase control and improve performance of its rougher flotation circuit. The customer was seeking a low-capital solution using its existing equipment and opted to install FLSmidth’s Adjustable Radial Froth Crowders. Radial Froth Crowders Installation of the crowders required no cutting or welding and was completed during a scheduled downtime. With no required permanent structural changes to the cell, modifications could easily be reversed if the customer chose. After installation of the package on just one row of its rougher flotation cells, the customer noticed significant improvements to its operation. Operators were able to decrease reagent consumption, increase the froth phase depth by 3 to 10 cm, and ultimately improve the downstream operations by stabilising concentrate mass flows. With the economic gains seen from the retrofit’s improved performance, the mine retrofitted the remaining two concentrator plants with the same type of adjustable radial froth crowders. Customer 3 – Froth Camera A mine in western Canada contacted FLSmidth with concerns about frequent variations in its copper grade, along with low recovery numbers in its flotation circuit. FLSmidth determined that the frequent variations were caused by poor setpoint control and selection, and that a software solution would provide immediate benefits without a large capital investment. The three-part solution utilised a combination of Model Predictive Control (MPC), fuzzy logic and FLSmidth’s newest technology in froth vision systems, to improve recovery by 4% at the desired grade with less variation. The first step was to ensure stabile level control throughout the flotation circuit. This was accomplished by controlling the dart valve positions directly using an MPC controller which greatly reduces setpoint error and variation. This process ensures that when a level setpoint is sent to a cell, that the dart valve position will be adjusted to reach the desired level set point in a quick and efficient manner. A mine in western Canada contacted FLSmidth with concerns about frequent variations in its copper grade, along with low recovery numbers in its flotation circuit. FLSmidth determined that the frequent variations were caused by poor setpoint control and selection, and that a software solution would provide immediate benefits without a large capital investment. The three-part solution utilised a combination of Model Predictive Control (MPC), fuzzy logic and FLSmidth’s newest technology in froth vision systems, to improve recovery by 4% at the desired grade with less variation. The first step was to ensure stabile level control throughout the flotation circuit. This was accomplished by controlling the dart valve positions directly using an MPC controller which greatly reduces setpoint error and variation. This process ensures that when a level setpoint is sent to a cell, that the dart valve position will be adjusted to reach the desired level set point in a quick and efficient manner. Summary With these advanced level sensors, actuators, radial froth crowders and froth cameras – installed individually or combined as a package – FLSmidth has proven its technology will allow for quicker reactions to flow and slurry density changes, greatly improving the performance of flotation machines. Better froth phase control methods can not only improve metallurgical performance in existing operations, but also allow performance prediction in greenfield operations.
Philippine Resources - November 28, 2021
Optimum froth recovery floats into view
Froth Recovery Upgrade package The flotation process can be divided into two stages: formation of the bubble-particle aggregates in the slurry and recovery of these aggregates in the froth. Historically, most attention – both from the theoretical and practical point of view – has been given to the first part of this process. But due to a newly developed instrumentation package, optimising froth recovery rates is now set to deliver real dividends. “It is probably no exaggeration to say that the potential from augmenting froth recovery rates – in terms of what more efficient control of the level, residence time in froth and pulling rates could deliver – was only recognized a few years ago by the industry,” commented Dr. Dariusz Lelinski, Global Product Manager for Flotation, FLSmidth. “This is because it was assumed that there are no losses during transport from slurry to the launder. It was only a few years ago it was measured that the loses are typically 50% and can reach as high as 90% for coarse particles. What it means is that 50% (averaging over all sizes) of particles must be captured again after detachment in froth phase.” “Our goal was to increase the probability of recovery of particles in the froth phase, especially coarse ones. There is no simple way to achieve it, because of it we came up with combination of instruments and devices flexible enough to achieve our goal in majority of flotation applications,” explains Lelinski. Equally applicable to sites operating with either self-aerating WEMCO® flotation cells or externally aerated nextSTEP™ machine, the newly developed froth-recovery instrumentation package could be a game-changer in flotation recovery. The solution comes from the recognition that the combination of exact slurry level measurement, accurate control of flow using redesigned dart valves and new Festo actuators (designed specifically for FLSmidth) allows for superior control of the froth phase. This in turn results in quicker reactions to flow and slurry density changes, which will dramatically improve performance of flotation machines. The conventional way to influence froth recovery is a combination of changes to froth height (improved by new actuators and dart valves), froth crowding (in the middle of the cell without the possibility of adjustment after installation and not influencing the most active part of the froth surface), and number of radial launders. “All these changes are still possible while using FLSmidth froth recovery package,” says Lelinski. “The most difficult part is froth recovery at the end of the row; there is not enough of hydrophobic particles to form stable, deep froth and a large percentage of these particles is left unrecovered.” “Our package allows not only to recover these particles, but to control required balance between recovery and grade in this part of flotation circuit. So overall, you get better results, but it also gives you another degree of process control, not only during difficulties of froth formation, but during normal operation allowing to more flexibility in selecting grade-recovery relationship.” Adjustable Radial Froth Crowders (ARFC) Central to the froth recovery package are Adjustable Radial Froth Crowders (ARFC) that were recently developed in-house by FLSmidth. The ARFCs are mechanical devices enabling increase of either recovery or grade regardless of amount of froth formed at the top of the machine. They allow for much higher pulling rates (recovery) or much deeper froth (grade) which is currently hindered by top of the flotation machine geometry. Froth Camera Froth cameras are a flotation instrument of central importance, as they allow precise monitoring of the froth phase. Our froth camera systems utilize a combination of Model Predictive Control (MPC), fuzzy logic, and the newest technology in froth vision systems to provide optimised set point selection in real-time. This system combines Deep Neural Networks (DNN) technology and object detection with traditional froth measurements such as velocity and stability to create a cutting-edge system which will optimize each individual flotation cell with the most comprehensive information available. Multisense level sensor (left) and Festo actuator (right) Alongside these elements are improved and redesigned actuators, developed in cooperation with Festo, and a new and improved level sensor, which monitors both the slurry and froth positions with the MultiSense probe, provided in cooperation with HyControl. The final piece of the package are redesigned dart valves (typically in a hinged dart valve configuration), which are the result of an in-house, value engineering project. “We are excited to deliver this complete package to our customers. All the elements working together in combination with radial froth crowders, means this package will deliver better recovery at the same grade or increased grade at the same recovery, making this package better that the sum of all parts.”
Philippine Resources - May 26, 2022
Legal framework needed for gov’t to invest in nuclear power plant
Department of Energy (DOE) Undersecretary Gerardo Erguiza Jr. said there is a need to amend the Electric Power Industry Reform Act (EPIRA) to enable the government to invest in nuclear power plants. This, as the incoming administration has expressed its support in considering a nuclear power plant to be part of the country’s energy mix. “As of now, the government does not have the ability to put up conventional nuclear power plant because the National Power Corp. does not have mandate on this,” Erguiza said in Filipino during the Laging Handa public briefing Wednesday. With the privatization of the power sector under the EPIRA, the government could not enter into power generation. “But we can align together, with the drafting or putting up of the regulatory framework, we can amend our laws to include the government among those that can fund a nuclear power plant,” he added. Erguiza said that based on studies of the Korean Hydro Nuclear Power Company of South Korea and ROSATOM of Russia, they have found out that the Bataan Nuclear Power Plant (BNPP) can still be rehabilitated. According to ROSATOM, an investment of around USD3 billion to USD4 billion is needed to revive the BNPP. Presumptive President Ferdinand “Bongbong” Marcos Jr. earlier mentioned that part of his energy agenda is to revive the BNPP to become an additional source of clean and cheap power. On the other hand, Erguiza said the government can invest in power generation using small modular reactors, the latest nuclear energy technology, in missionary areas that are not connected to the grid.
Philippine Resources - May 26, 2022
Dutch gov’t backs SMC, Boskalis in P740 billion Bulacan Airport project
Photo credit: Palafox Dutch gov’t backs SMC, Boskalis in P740 billion Bulacan Airport project San Miguel Corporation (SMC) received its strongest support yet for its game-changing P740-billion New Manila International Airport (NMIA) project in Bulacan following the approval of the Dutch government of an export credit insurance (ECI) for the project’s land development phase. The approval comes after over a year of rigorous review of the project’s long-term environmental and social impact mitigation measures to ensure that the multi-billion project is done with sustainability in mind and aligned with the country’s climate ambitions. The Dutch government, represented by Atradius Dutch State Business (DSB), extended the ECI to Royal Boskalis Westminster N.V., to cover its EUR 1.5 billion contract for land development works at the airport project site in Bulakan, Bulacan. The NMIA project is the largest in Boskalis’ over 100-year history, and is also the largest export credit agency (ECA) insurance policy granted in the 90-year history of Atradius. SMC President and Chief Executive Officer Ramon S. Ang thanked the Dutch government for its support to NMIA, a project seen to catalyze sustainable economic growth for the Philippines, especially post-pandemic. It is seen to deliver over a million jobs to Filipinos. “This is a significant milestone not only for San Miguel and the NMIA project, but for the entire country. With this, we are closer to our dream of having a world-class, future-ready, and sustainably-built international gateway, proudly built by Filipinos for the Philippines. This also validates our work with Boskalis to ensure that this project is done right, and will provide long-term economic, environmental, and social benefits to our host communities and Bulacan province,” Ang said. In a statement posted on Boskalis’ international website, its CEO Peter Berdowski, said: “I am very pleased that all the hard work with a large team of experts has been successfully completed (today). For more than a year, we have worked intensively with Atradius DSB to ensure that the construction of the new airport will take place in a socially responsible manner.” He added: “In collaboration with Atradius DSB, the Dutch embassy, we succeeded in developing a broadly supported plan with an eye for the local community and the preservation of biodiversity. I would like to thank all those involved for their contribution to the positive decision of the State.” In the same statement, Atradius DSB Managing Director Bert Bruning said: “This project is unique on so many levels. Firstly, of course, as a very important contract for our client Boskalis, but also for us, as the largest ECA policy in our 90-year history,” he said. “In addition, I am proud of the fact that together with Boskalis and San Miguel, by keeping up the dialogue, we were able to ensure that the project is to meet international standards in the field of environmental and social conditions. In doing so, we have not only contributed to making this wonderful contract possible built also really made a difference together for the local communities and nature.” As part of the ECI process, a large group of experts from San Miguel, together with Boskalis and four renowned consultancy firms, conducted an extensive environmental and social impact assessment in accordance with the highest international standards. This process also included the conduct of impact analyses and compensation packages for adverse effects of the project. “This shows that the airport project and our environmental and social mitigation plans are not only sound, but robust and strong, given they can pass not only international standards but the exacting requirements of the Dutch government. It is another testament to the ability of Filipinos to be world-class,” Ang said. “We will continue to work with Atradius, the banks, experts, national and local government, and all stakeholders to ensure we will build this project in a sustainable manner and in compliance with the highest international environment and social standards,” Ang reaffirmed. added. The airport project will feature four parallel runways, a world-class terminal, and a modern and interlinked infrastructure network that includes expressways and railways. Article courtesy of San Miguel Corp
Philippine Resources - May 25, 2022
CTPCMC Allocates 7.7M for COVID-19 Initiatives
Article by: Roniel R. Arguillas - CTPCMC ICE Officer BAYANIHAN AMIDST THE COVID-19 BATTLE In order to protect and improve the lives of the people within the host and neighboring communities pursuant to Republic Act (RA) No. 11469 or the “Bayanihan to Heal as One Act”, CTP Construction and Mining Corporation or CTPCMC allocated 7.7 million pesos intended for the implementation of projects, programs, and activities (PPAs) on COVID-19 prevention. Through its Social Development and Management Program (SDMP) under Adlay Mining Project (AMP) and Dahican Nickel Project (DNP) the company implemented essential PPAs in the year 2021. The beneficiaries of PPAs were from the Host and Neighboring communities specifically Barangay Adlay, Barangay Dahican and Municipality of Carrascal. With an allocated budget of P2,060,803.78, a Covid-19 Assistance Center was put up to be the second line of support to the host communities if their existing Isolation Rooms have been fully occupied. The company’s employees and their dependents are to be prioritized in the center. The center is offering services which include free isolation room for those who are identified and confirmed as covid-19 patients, free vitamins, and over-the-counter drugs, 24/7 monitoring by health personnel and stand-by oxygen concentrators. Another PPA was the provision of 59 medical equipment and kits to Barangay Adlay. The provision included pulse oximeter, thermal scanner, LCD full digital ultrasound machine, hospital bed and refrigerator as vaccine storage. The turnover was done on December 14, 2021, held at Barangay Hall of Adlay. It was attended by Engr. Charlo R. Basadre CTPCMC Resident Mine Manager, Charid O. Cuadrillero ComRel Manager, Hon. Norberto O. Rubi Jr. Barangay Captain, and Raquel Bungcaras assigned nurse. “These are very essential and a huge help to the key front liners and to the people within the community.” Hon. Rubi said during the turnover. The company also provided two SDMP Emergency Response Vehicles for health-related emergencies.