By Sasongko Nurwendo, Act. KPC drill & blast manager
Case study
PT Kaltim Prima Coal (KPC) is a major open pit coal mining company operating in the regions of Sangatta and Bengalon, East Kalimantan, Indonesia. The combined mining concession area is 61 543 Ha with KPC managing one of the largest open- pit mines in the world which produces around 60 million tonnes of (Run of Mine) ROM coal per year.
he mining method utilised is truck and excavator within multiple pits which are managed by two mining divisions; Mine Owner Division (MOD) and Contract Mining Division (CMD). AECI Mining Explosives operates within the CMD area of the KPC operations.
KPC coal production began in 1992 and mines over 450-million Bank Cubic Metre (BCM) of overburden material per year. In 2021 KPC mined 453-million BCM of overburden by consuming 85 000 tonnes of bulk explosives to produce 56.4-million tonnes of coal. Approximately 83% of the overburden requires drilling and blasting to enable efficient excavation.
KPC’s mining activity generates over 8-million liters of used oil per annum (2010-2021). Prior to 2011, used oil in explosives was only used for ANFO whilst the remaining oil was shipped to a local licensed waste processor.
BUSINESS CHALLENGES
The required volume of Bulk Explosives at KPC is in the range of 80 000-100 000 tonnes per year and 65% of that requirement is supplied by AECI Mining Explosives at the CMD Operations.
KPC has identified that fuel and explosives consumption represent two of the main operating costs for the mine. Consequently, KPC is actively and constantly identifying and implementing more efficient and safe blasting processes to reduce consumables costs including the saving on diesel for emulsion manufacturing. To support this, in 2016 KPC obtained a permit to introduce and utilise used oil to replace diesel up to 80%
in the emulsion formulation and in conformance to the local standard SNI 7642:2010 (SNI, Standar Nasional Indonesia) followed by an upgrade to 100% replacement in 2017.
Used oil is known to contain elements, which are harmful to the environment and handling this waste stream in a cost effective and environmentally responsible way is challenging. In order to categorize the used oil as a reusable resource and not as a hazardous waste material, a strict specification for the quality of the used oil is necessary. The recovered used oil from a given workshop facility or source is delivered to a specific settling tank where the used oil is allowed to settle for a number of days. Water, solids, and oil sludge are drained off the bottom of the tanks at regular intervals until the stored used oil is approved for use in the fuel blend component of the emulsion for the manufacture of the final S300 Eco emulsion.
The S300 Eco series is designed to incorporate used oil with the aim to protect the environment and reducing the carbon footprint. AECI Mining Explosives is one of the pioneers in the use and application of used oil as a replacement for diesel in emulsion manufacturing.
Advanced emulsifier technology combined with high quality used oil has allowed for the successful replacement of diesel in the manufacture of bulk emulsion explosives. The development of suitable emulsifiers has enabled AECI Mining Explosives to replace diesel up to 100% without reducing the bulk explosive performance. Energy and performance have in-fact increased through the combination of these technologies and it is safe to say that AECI Mining Explosives quite possibly produces the best emulsion explosives in the world today.
Back in January 2011, AECI Mining Explosives commenced trials at KPC with 10% replacement of virgin oil, ramping up to 100% in 2017. This is testament to the two Companies’ relentless drive for continuous improvement.
The performance of the S300 Eco Series bulk explosive products has been consistent with all levels of used oil replacement and monitored regularly on the bench by conducting regular Velocity of Detonation (VOD) tests. The product has proved to be stable and performed within its specification with excellent blast results achieved.
Since the time of introducing used oil for emulsion manufacturing, the saving in diesel consumption for the period of 2011-2021 has been approximately 25.5 million liters or annual average saving of 2.3 million liters per year.
“The KPC Drill and Blast department is committed to adhering to the country’s stringent environmental regulations. In realising this with our commitment to greener operations, the team understands that there is an opportunity to reduce the proliferation of used oils, which is categorized as a hazardous pollutant. Part of the synergies explored with AECI Mining Explosives is to ensure that used oils from the Mine’s production processes will be absorbed as part of AECI’s explosive formulations.
This opportunity for improvement will not only significantly reduce the blasting cost, but also assist KPC with managing the used oil produced from its operations. The Group expects that AECI Mining Explosives Indonesia will maintain, and where possible, improve on the current excellent emulsion technology and also to continue bringing new improvement ideas to KPC.”