PT. Promincon Indonesia (PMC) was founded in 2011 in Jakarta by Mike Andrews and George Bonney. The goal was to provide reliable core drilling services across the Indonesian archipelago with easily maintained and portable drill rigs.
Today, the company operates as a private Indonesian entity from its headquarters in South Jakarta and focuses on achieving client satisfaction at an affordable price with a simplified ‘all-in’ meter rate. PMC prides itself on operating safely, minimizing environmental impact, and meeting or exceeding client requirements. The company’s achievements include many successful projects, core recovery rates of 96–97% or higher, being eight years LTI-free at the Martabe site, and multiple diamond drill holes exceeding depths of 1200 m (3937 ft).
Experienced team
PMC employs a base core of employees in the field, including an expat drilling manager, supervisors, drillers, mechanics, logistics, safety, and administration personnel. The remaining employees are always recruited from surrounding villages to support the local economy and offer alternative employment. Many of these casual employees have shown initiative and gone on to become full-time employees. We are also proud to say that PMC has a high female participation rate.
The company ensures compulsory POM (Pengawas Operasional Madya—Intermediate Operational Supervisor) and POP (Pengawas Operasional Pertama—First Operational Supervisor) certifications for supervisors and drillers. It also provides ongoing training through on-site videos covering Standard Task Procedures (STP) and 4WD training. Every site is staffed with qualified HSE personnel and all senior personnel are trained in First Aid as a minimum requirement.
Drill rigs: The PMC models
The company manufactures its rigs in-house, making the PMC200, PMC400, PMC700, and the PMC1200 models, with rig sizes being the rated drilling depths in NQ. The rigs are made to be skid-mounted or heli-portable in configuration. PMC’s current fleet includes 23 rigs and three underground rigs.
The PMC400 is powered by a single 57 hp forward engine, while the 700s and 1200s are powered by twin forward engines. Each series of portable drills is the same, and many components are interchangeable. As the majority of PMC’s work is heli-portable, all rigs can be broken down into components weighing less than 600 kg (1323 lb) for PMC1200 and less than 430 kg (948 lb) for PMC200, 400, and 700, making them easier for helicopter lifts. To assist heli-moves, PMC has manufactured, tested, and certified lifting cages for equipment and 200 L (53 gal) diesel drum slinging. Once the rig base has been secured on the drill pad and components have been transported by helicopter, rigs can be operational within six to eight hours.
In addition, each PMC drill is equipped with an extensive range of items such as water supply pumps, mud mixing pumps and tanks, drill rods, all downhole drilling items, poly pipe water line, hand tools, generator set and lighting equipment, and a portable welder. Rigs also have communication equipment for remote areas, downhole survey cameras, and orientation tools if required.
Indonesia: A challenging environment
Indonesia is an archipelago of islands, which presents numerous issues with regard to mobilizing equipment and supporting jobs logistically. A single job may require transport by truck, ferry, and helicopter to get supplies to the site, and that can take from days to weeks.
Further challenges arise from the weather. Indonesia is a tropical country and has two seasons: the dry season, which runs from April to November, and the wet season, from November to April. In general, the climate ranges from 20°C to 35°C (68°F to 95°F), with cooler temperatures at higher altitudes. Significant rainfall in the wet season is common, causing flooding, washed-out roads, and landslides. For example, northern Sumatra (or Sumatera, as locals call it) experienced massive rainfall at the end of November 2025, causing significant infrastructure damage, the loss of houses and entire villages. As part of the Pacific Ring of Fire, Indonesia has around 130 active volcanoes.
Dealing with mountainous terrains, wet season weather, including floods and landslides, as well as navigating local labor regulations, local governments, and environmental issues, can take a lot of planning. PMC is well experienced in these operating environments.
Drilling in Indonesia
Drilling locations in Indonesia can vary greatly, from being next to rice paddies to isolated locations high in the mountains. Some sites have fly camps, which are solely dependent on helicopter support for food, fuel, and supplies, requiring excellent logistics from the PMC management, while others are at mines and fully supported.
Additionally, drillers often face varied types of rocks, including dense volcanic rocks and softer sedimentary layers. This means that PMC crews need to choose the right drill bits and adjust their drilling techniques to optimize penetration rates.
Water management is also crucial, as the tropical climate can lead to high groundwater levels, necessitating the use of effective mud systems to stabilize boreholes and prevent collapse. The wet season brings high risks of landslides, which have resulted in PMC equipment loss on several occasions but, fortunately, no injuries. The other major concern in the wet season is the huge thunderstorms with multiple lightning strikes. Rigs must be shut down until the storms clear.
In the dry season, the opposite can be a problem. Numerous creeks and streams drying up requires pumping water from 1 km (0.6 mi) or more away with vertical lifts of up to 400 m (1312 ft). Staging pumps are sometimes needed to assist with the distances and lifts. Using the correct mud systems is also an important part of trying to manage water loss in extremely broken ground. At times, drilling must stop while waiting for the water supply to be replenished.
Because of the usually fractured or soft formations, PMC specializes in drilling predominantly PQ3, HQ3, and NQ3 sizes. In addition, our rigs are designed so that they can drill from 90 degrees to horizontal with minimal modifications. PMC also provides a range of geotechnical services, including standard penetration testing, undisturbed samples, installation of piezometers, and monitoring bores.
Case studies
With 15 years of experience, PMC has the drilling equipment, the expertise, the logistical resources, and the team to deliver reliable services at affordable prices in the challenging operational environments across Indonesia. The company’s strong track record is reflected in its many successful projects.
Way Linggo project
PMC started drilling for Natarang Mining in 2012 at their Way Linggo project in southern Sumatra. Initially, two PMC400s and two PMC700s were being used. The job expanded and required additional drills, including a PMC1200 rig and the purchase of three underground rigs to complement the surface rigs. At Talang Toha, 29 km (18 mi) from the Way Linggo mine site, PMC established an office, accommodation, mess hall, storage, and maintenance facilities. PMC provided drilling services to Natarang until 2023, when they purchased their own rigs. During that period, PMC drilled over 150 000 m (492 126 ft) of surface and underground coring.
Martabe Mine
A cornerstone of PMC’s history is the long-standing relationship with PT. Agincourt Resources at their Martabe gold mine in North Sumatra. PMC recently secured the tender to continue exploration drilling at the Martabe Mine until October 2027, marking 15 consecutive years on site. In that time, PMC has completed around 750 000 m (2 460 630 ft) of exploration and geotechnical drilling, with the deepest hole drilled being 1244.5 m (4083 ft) at a 65-degree angle. In September 2025, the company achieved eight LTI-free years at Martabe, and this unblemished record is still ongoing.
At its peak in 2021, PMC had 15 rigs operating at Martabe. Currently, it has a mixture of exploration and geotechnical rigs on site, with the number varying depending on the mine site’s requirements. In his reference, the previous Chief Geologist of PTAR Martabe stated:
‘PMC had up to 15 diamond coring rigs working at Martabe. On one occasion, they were required to ramp up over three months from five to 15 rigs, which was accomplished without any significant safety incident and no serious injuries or lost time.’
With the rugged, steep, and heavily forested terrain at the site, drill locations are generally only accessible by foot or helicopter. Preparation of drill pads is done manually, and often there are limits to the size of the pads. In very steep areas, sometimes drill platforms are cut out into the canopy of the trees and constructed from the available timber. Timber walkways are made from solid trees running parallel with thinner branches nailed across them to form steps.
The Martabe mine site is also the main base for all of PMC’s equipment. Drilling management, safety personnel, site administration, and logistics team are located here. The setup also includes light vehicle maintenance, an electrical workshop, a machine shop, a welding bay, as well as large stocks of spare parts. Our helicopter support team works from here too, loading and unloading loads of fuel, camp supplies, as well as the numerous core samples from the rigs.
The previous Chief Geologist of PTAR Martabe summarized:
‘I found PMC extremely professional to work with, and of equivalent or better quality and service than much larger, internationally based drilling companies. They were responsive to client needs and always willing to work with our requirements. PMC was flexible in its approach and provided a high-quality service. They operated in both mountainous forested terrain and within the mining operation with a high regard for safety, core recovery, and efficiency.’
The drilling market in Indonesia
The landscape has changed significantly, both on the client and contractor sides. In the early days, the clients were the big Australian, American, and Canadian explorers: Normandy, Newcrest, Newmont, BHP, Rio Tinto. Contractors were predominantly owned or run (or both) by expats: Boart Longyear was a significant player, along with Pontil (now Major Drilling), Maxidrill, Indodrill, and BMP.
Some mining companies withdrew from Indonesia, while others sold their interests to local firms. Meanwhile, local Indonesian drilling contractors have advanced significantly in terms of size, quality of equipment, and safety standards. They are now far more competitive and hold a large portion of the work. From a business point of view, it is becoming harder and harder for foreign, expat-run firms to compete against the ever-evolving Indonesian companies.
Looking ahead
As PMC is a relatively small company, the client is always dealing directly with the people who make the calls, ensuring clear communication and decisions that can be made on the spot without lengthy delays. This allows us to be flexible to the client’s requests and quick to react when variations to the original work order are required. PMC’s focus going forward is to maintain a stable client base to which it provides a complete drilling service safely and at a high standard.
For more information: Visit ptpmc.com
