Grasberg Block Cave mine: cave planning and undercut sequencing

This paper provides an update of the mine design, construction, caving progress and operations status of the Grasberg Block Cave (GBC) mine. Undercutting was initiated in September 2018 and drawbelling in December 2018. Undercutting is currently proceeding in three production blocks. Full production is expected in 2025, a 21-year time period between initial access development in 2004 to full production. Diluted ore reserves are about 959 million tonnes at a grade of 0.97% Cu and 0.73 g/t Au. The mine plan utilizes an El Teniente-style drawpoint layout on a 20 m x 30 m drawbell spacing, comprising some 2,400 drawpoints in a 720,000 m2 footprint. The drawpoint opening sequence comprises eight production blocks. Ore is transported via diesel-powered LHDs to a series of ore passes, then via loading chutes to a rail haulage system, which delivers the ore to a three-gyratory crusher complex. Crushed ore is transported to the mill stockpiles via dual inclined conveyors. Development and construction of the initial fixed facilities was completed in late 2018 and expansion of those facilities is ongoing to support production ramp up. Primary access for workers and materials is via the 6-km long AB adits. The service shaft for hoisting workers and materials from the AB adits’ level to the various operating levels was commissioned in 2016. The rail haulage central control system and initial haulage operating areas were commissioned in 2018. The first phase of the crusher/conveyor system was commissioned in mid-2018. Ventilation is provided through a series of large intake and exhaust drifts; four 5,000 kW main fans are operational, and a fifth fan will be commissioned in 2021. A 1,600 l/s pumping system will manage drainage from the mine. The initial stage of the pumping system is under construction and will be commissioned in 2020.

At PT Freeport Indonesia’s Grasberg mining complex, the Grasberg open pit is scheduled to cease production in early 2019. Mining of the Grasberg deposit will then transition to the underlying Grasberg Block Cave (GBC) mine, with initial undercutting currently planned for late 2018. The GBC is projected to become the district’s flagship underground mine for the next two decades. Early-stage production areas at the GBC are hosted within a heterogeneous rock mass. The footprint will be subjected to variable abutment and cave loading conditions. Mine design and sequencing adjustments, combined with customised ground support options, continually evolve to improve footprint reliability and permit a favourable transition between open pit and underground operations. This paper provides a snapshot of strategies employed to promote the successful caving operation at the GBC mine.

PT Freeport Indonesia is a mining company which includes mining, processing and exploration of ore containing copper, gold and silver. PT Freeport Indonesia operates in the highlands of Mimika Regency, Papua Province, Indonesia. PT Freeport Indonesia is committed to providing benefits to the community around the operational area, these benefits are realized through various social investment activities carried out with partners. This study aims to provide an overview of PT Freeport Indonesia's commitment in implementing community development and empowerment that has been going on for the last three years. The research method is carried out using qualitative methods in general, describing a research to be simpler and subjective. Data processing was carried out by studying literature using data from the social investment annual report of PT Freeport Indonesia. The results of this study provide a general description of PT Freeport Indonesia's commitment to implementing community development and empowerment in the operational are.

PT Freeport Indonesia menghadapi tantangan besar dalam mengelola dampak lingkungan akibat aktivitas pertambangan, terutama terkait pengelolaan air asam tambang (AAT) dan penyediaan air siap minum bagi masyarakat sekitar. Penelitian ini bertujuan menganalisis strategi dan teknologi yang diterapkan PT Freeport Indonesia dalam kedua aspek tersebut. Metode yang digunakan adalah studi literatur dari berbagai sumber, termasuk laporan keberlanjutan, jurnal ilmiah, dan penelitian terdahulu. Hasil pembahasan menunjukkan bahwa dalam pengelolaan AAT, PT Freeport Indonesia menggunakan beberapa metode utama seperti netralisasi menggunakan bahan alkali, penerapan lahan basah buatan (constructed wetlands), dan sistem pemantauan kualitas air secara berkala. Pendekatan ini terbukti efektif menurunkan kadar logam berat hingga di bawah ambang batas yang ditetapkan oleh Kementerian Lingkungan Hidup dan Kehutanan (KLHK). Di sisi lain, penyediaan air siap minum dilakukan melalui teknologi filtrasi, desinfeksi, dan reverse osmosis (RO), yang memungkinkan pengolahan air dari sumber lokal menjadi layak konsumsi. Air bersih tersebut didistribusikan melalui jaringan perpipaan dan stasiun pengisian air bagi masyarakat sekitar. Program ini tidak hanya mengurangi dampak pencemaran lingkungan, tetapi juga memberikan manfaat langsung bagi kesehatan dan kesejahteraan masyarakat. Dengan kombinasi teknologi canggih dan tanggung jawab sosial, PT Freeport Indonesia berhasil menunjukkan praktik pertambangan berkelanjutan yang memprioritaskan keseimbangan antara aktivitas industri, kelestarian lingkungan, dan kesejahteraan masyarakat.

Large scale block cave mining has been operated for over 30 years in the Erstberg Mining District in the province of Papua, Indonesia. The ore body is divided into four vertically stacked ore bodies: Gunung Bijih Timur (GBT), Intermediate Ore Zone (IOZ), Deep Ore Zone (DOZ), and Deep Mill Level Zone (DMLZ). The GBT and IOZ mines were closed on 1993 and 2003, DOZ mine is in its peak production performance 80 ktpd, and DMLZ mine is still in the development stage to prepare mine infrastructures. This situation generates gradual downward settling of the surface or subsidence. Significant deformation changes at the surface by block caving subsidence could damage the mine’s infrastructures in surface and underground and also affect geological structures overlying the mining areas which may result in surface impacts on the natural geomorphology and land use.
 
 In this paper, integrated system based on Geographic Information System (GIS) platform applied to predict ground movements due to underground mining. Deep Ore Zone (DOZ) block cave mine is studied for subsidence prediction. The mining extraction thickness model is obtained from height of draw (HOD) observed data. Subsidence Engineering Handbook (SEH) of empirical model and measured data from mining fields is used for subsidence calculation parameters. The calculations were performed in GIS. The maximum vertical displacement has been predicted about 12m by means of full caving mining method.
 
 Keywords: Ground movements, block caving, GIS, underground mining, and subsidence

The implementation of CSR during the COVID-19 pandemic was constrained due to an uncertain and unprecedented situation, which had an impact on the implementation of CSR program. The purpose of this study is to analyze the CSR program in the health sector during the COVID-19 pandemic carried out by one of the State-Owned Enterprises in Indonesia, namely PT Freeport Indonesia (PTFI), which has been known as one of the companies that has a significant impact to Papua and Indonesia as well. PTFI continues to carry out CSR programs in the health sector as in previous years, as well as providing assistance for the prevention of COVID-19. However, although CSR programs in the health sector are still being carried out, few community empowerment programs are provided, and PTFI has not carried out community empowerment in dealing with health crisis. The implementation of PTFI's CSR program in the health sector during the COVID-19 pandemic faced many challenges. The challenges are mostly technical in nature due to social restrictions and health protocols that must be carried out, as well as matters related to infrastructure to facilitate working remotely.

In a competitive and dynamic business era, contractor performance management is crucial for achieving operational efficiency and competitive advantage. This research aims to develop a conceptual framework to enhance contractor management and performance, addressing a key challenge in the business sector, which is the availability of electric locomotives (ellocos) performance in GBC mine in PT Freeport Indonesia. By adopting the DMAIC (Define, Measure, Analyze, Improve, Control) approach, this study outlines systematic steps beginning with a deep understanding of user needs and expectations regarding contractor performance. The study employs a qualitative method to identify the root causes of the decline in elloco performance through the analysis of contractor management and performance. The DMAIC approach is applied to improve contractor performance, with periodic monitoring every six months or annually. Data is collected through observation, unstructured interviews with supervisors, and documentation. Data analysis is conducted using the Miles and Huberman model with a triangulation approach to ensure the validity and reliability of the findings. The results indicate that implementing this conceptual framework provides clear and effective guidance for organizations in enhancing contractor performance. The use of the DMAIC approach ensures that each step in the research process is carried out carefully and systematically, helping organizations address the challenge of ellocos performance availability and achieve their business goals. The implementation of this conceptual framework is expected to improve contractor performance and well-being in the dynamic business context.

Physical modeling of high extraction columns in block cave mining

Hydraulic fracturing can be used for preconditioning in block cave mining. Microseismic monitoring is one of the techniques used to determine the orientation, extent and time evolution of the hydraulically-generated fractures. Data are recorded continuously at significantly higher frequencies than currently used in routine seismic monitoring in mining environments, and the data analysis is accordingly more complicated. Microseismic monitoring was performed as part of the hydraulic fracturing programme at Ridgeway Deeps Block Cave. The seismic data that are recorded during a typical fracture session have been described in detail. Frequency filtering and time domain methods are used to isolate the individual seismic events. A straight-ray method is used to estimate source location. A group of seismic events is then relocated with a double-difference method and the locations are used to describe the hydraulic fractures. Several hundred events from several different fracture sessions were located using this technique. For many fracture sessions, the locations are clearly planar, and estimates of strike and dip could be obtained. Fracture planes from consecutive fracture sessions were compared. The time evolution of individual fracture sessions was analysed and used to provide estimates of propagation rates. Criteria have been discussed for applying the technique to other hydraulic fracturing programmes.

This community service program aimed to enhance the leadership capacity of the elected board members of the Amungme and Kamoro Community Empowerment Foundation (YPMAK) in Timika through active listening training. The training was organized by Pusat Studi Pengembangan Bisnis dan Industri Kreatif (Pusdi-PBIK), Padjadjaran University, in collaboration with YPMAK and PT Freeport Indonesia, involving five elected board members. The training methods included lectures, discussions, role-playing, and evaluations, with materials covering the importance of active listening, its challenges, benefits, and practical techniques such as paraphrasing, maintaining eye contact, and avoiding interruptions. The results indicated active listening supports better decision-making, improves interpersonal relationships, and fosters trust. Challenges such as emotional and external noise, as well as the disparity between thinking speed and speaking speed, can be mitigated through effective communication techniques. It is concluded that active listening is an essential leadership skill that enables YPMAK board members to understand community needs, strengthen relationships with stakeholders, and enhance the success of empowerment programs. Implementing an organizational culture of active listening through advanced training and real-world simulation is recommended to ensure the sustainability of its positive impacts.

Two years ago, my mom handed me the article, “Below a Mountain of Wealth, a River of Waste,” from The New York Times, describing Freeport-McMoRan’s mining activities in Papua New Guinea. After reading “Below,” I knew that the world had to change; the injustices that Papuans were experiencing could not continue for long without retribution. 
 “[A]n American transnational mining company called Freeport-McMoRan…operat[es] the largest gold mine on Earth, not in Africa but in the heart of West Papua” (Leith xv). Freeport-McMoRan Copper and Gold Inc. is the best known subsidiary of PT Freeport Indonesia, operating in West Papua, New Guinea. Freeport’s operation there has resulted in the complete remodeling of the society and economy. West Papua is a province of Indonesia; it, along with Papua New Guinea, comprises the island of New Guinea. West Papua has a population of approximately 800,000 people, making it one of the smallest Indonesian provinces. Due to its small size and remoteness, Freeport was able radically to change the social structure there; often these changes occurred without Papuan consent.

The purpose of this research is to identify and manage toxic and hazardous waste, called THW, present in the Concentrating Division of PT Freeport Indonesia. The identification and management process of this waste was based on the Indonesian Government Regulation Number 22 of 2021. Furthermore, this research uses a qualitative approach where data was collected by field observations and secondary data collection. The data collected incorporated different types and weights of the THW generated in the last 5 years. These wastes were identified based on their level of hazardousness as well as their source. The results showed that the total THW weight generated in the last 5 years was approximately 975,814 kg and the total waste generation rate is 16,264 kg/month. In addition, the most dominant waste types generated include grease waste, fire assay waste, and used oil. Various waste management processes were conducted in this study. They include reduction, storage, collection, and utilization. The identification and management of THW in the Concentrating Division is almost consistent with the Indonesian Government Regulation Number 22 of 2021. However, the process of waste collection in the target area is not yet consistent with this regulation because the Waste Transfer Point (WTP) is still under construction.

In 1967 the transnational mining company Freeport was the first foreign company to sign a contract after Sukarno was sidelined by Suharto. Eventually, Freeport-McMoRan Copper and Gold, through its subsidiary PT Freeport Indonesia, came to operate the biggest gold mine and lowest extraction-price copper mine in the world in the isolated mountains of the Indonesian province of West Papua. It also became politically and economically significant to the Suharto regime. In the absence of the central government, the American mining company became the de facto developer and administrator of its concession in West Papua while in the United States it served as an important political lobby group for Jakarta. With Freeport becoming the largest taxpayer in Indonesia, one of the largest employers, and eventually running one of the largest socioeconomic programs in the republic, it was described by Suharto as essential to the nation's economy. Freeport's importance encouraged the development of mutually beneficial and supportive relationships between the company, the Indonesian president, his military, and the nation's political elite. In return, Freeport was politically and physically protected by the regime. Eventually, Freeport's financing of the president and his cronies' interests in the company threatened to see Freeport violating the United States' Foreign Corrupt Practices Act. Today Freeport's past relationship with Suharto has made it a high-profile target for anticorruption reformers in Indonesia. Because of the pivotal economic role the company continues to play in Jakarta and West Papua, any question of future independence for the province will be inextricably linked to the company.

The Deep Mill Level Zone (DMLZ) is one of the underground mines operated by PT Freeport Indonesia (PTFI), located approximately 1,500m below ground level and consists of multiple production blocks on the same extraction level. The DMLZ experienced significant seismic activity, and to mitigate the risk, Production Block (PB) 4 was elevated 225m above the current DMLZ footprint elevation. PB4 sits adjacent to the existing and future cave formed by the lower production blocks. The development of DMLZ PB4 mine started in late 2021 following conceptual and pre-feasibility level studies, and development continues concurrent with detailed engineering targeting undercutting start in early 2025. This paper presents the challenges encountered, evolution of the design and mining strategy of PB4 during the rapid development and engineering of this new block. Lessons learned and ongoing work related to project and change management, undercutting plan, development schedule, and overall mine design are discussed in the paper.

Detection of the presence of arbuscular mycorrhizal fungi (AMF) on marginal land within degrading reclamation effort land is very important to support the success of such reclamation. The purpose of this study is to determine the presence of AMF in the root rhizosphere of fern plants Equisetum debile, Pteris radicans, and Nephrolepis hirsutula that grow in the tailing area of gold mine Timika. The study used a survey method to isolate AMF from the root rhizosphere of fern plants in the gold mine tailing deposition area of the Modified Ajkwa Deposition Area (ModADA) of PT Freeport Indonesia (PTFI) in Mimika Regency, Papua, Indonesia. AMF infection was tested using a trypan blue staining method, while the calculation of the percentage of infection was carried out by a slide method. The presence of AMF spores was detected by a wet sieving method. The results of the study showed that there were AMFs in the root rhizosphere of the three types of fern. However, based on the observation of infection of the plant root system, there were only P. radicans indicating to interact with AMF, while E. debile and N. hirsutula were not associated with AMF. There were 54. 44% of infection at the root rhizosphere found in P. radicans and number of spores ranged from 8 to 12 per 10 g of soil samples. Although there were no infection of AMF on the root rhizosphere of E. debile and N. hirsutula, however there were 4.33 and 11 spores per 10 g of soil samples of both plant rhizosphere respectively. Based on morphology, it can be identified that the types of AMF were member of genus Scutelospora, Glomus, Claroideoglomus, and Acaulospora.