DM30 II: Redesign of the Low Pressure DM30 Hole Drill by Atlas Copco

Topics Covered

Introduction
Key Advantages of DM30 II
Role of DM30 II in Prima Sarana Gemilang (PSG) Mine in Indonesia
Conclusion
About Atlas Copco

Introduction

The island of Kalimantan has approximately 70% of Indonesia’s drills operating in the coal industry, thus representing the country’s major blasthole market. Larger models used for blasthole drilling include the Atlas Copco DML and DM45 rigs. With the launch of the new DM30 II, Atlas Copco provides new option in blasthole drill rigs in the 7 ⅞-inch hole class for miners. The DM30 II is the redesign of the low-pressure DM30.

DM3011 Mid-sized rig by Atlas Copco.

Key Advantages of DM30 II

In the coal region of Kalimantan, the DM30 II has been taking on the DM45, maintaining its production and tonnage at similar properties. According to Jerry Murthi, second generation owner of Nariki Minex Sejati, the DM30 II enables the company to drill larger holes and suitably sized patterns yet much smaller holes when required, thanks to the mid-sized rig’s 7 ⅞-inch capability. Operating at about 15 mine properties, Nariki has larger drills, and many DM45 rigs, but virtually never requires a 9 inch or larger hole.

Jerry Murthi. Second generation owner of Nariki Minex Sejati drilling organisation.

Murthi also informed that the smaller drill also helps the company’s customers in planning. The company mostly drills 7-8-8 or 8-8-9 bench and pattern and the maneuverability of the DM30 II provides the capability to the company to meet the requirements of the mine engineers. The configuration of the DM30 II and the DM45 is listed in Tables 1 and 2.

Table 1. DM30 II Configuration.

Shock sub PN 92003968 14 inch sub
Top thread saver sub PN 92001095 5.5 inch OD x 5 inch sub
Drill pipe PN 92003339 5.5 inch OD x 30 foot sub
Bit sub PN 92009655 5.5 inch OD x 32 inch sub
Deck bushing PN 2310062636 5.5 inch ID
Drill bit PN 93001010 type F35 7 ⅞ bit size

Table 2. DM45 Configuration.

Top sub PN 20306252900 6 ¼ inch OD x 29 inch sub
Drill pipe PN 21206253601 6 ¼ inch OD x 30 foot sub
Bit sub PN 21506253200 6 ¼ inch OD x 32 inch sub
Deck bushing PN 92003844 6 ¼ inch ID x 10 inch OD
Drill bit PN 93001010 F35 size 7 ⅞ inch

Role of DM30 II in Prima Sarana Gemilang (PSG) Mine in Indonesia

Although the PSG mine opened two years before, the first drill rigs were brought to the mine in recent time. Before beginning the drilling at the mine, ripping to crumble the sandstone and claystone formation is assessed. The formation has the hardness, which leads to more productive excavation with less wear on the excavation equipment during blasting. Ripping generated only 25-30% of the output of blasting and drilling per hour.

The formation ruptures well with an 8- or 9-meter burden and 9- to 10-meter spacing. Drill and Blast Supervisors Jos Bernadus Manulang and Handik Setiawan were told that they are still fine-tuning the pattern depending on the variations of the two pits in clay or sandstone rock. They are challenged with a layer of coral in Pit 1 that reduces productivity from an average 56m/h down to 40m/h. Drilling with the DM30 II yields an average of 48m/h in Pit 2.

For comparison, the nearby Buma Binungan mine reaches 63m/h in the mostly sandstone formation with its Atlas Copco DM45. Although the penetration rate is more, the associated costs are also higher with the larger drill. The DM30 II is equipped with a 29.7m3/min (1050cfm), 7.5bar (110psi) compressor, while that parent DM30 design features a 900cfm compressor and the DM45 features a 34.0m3/min (1200cfm), 7.5 bar (110psi) compressor.

At PSG, eight seams are mined, with a coral stratum encountered in Pit 1 at the third seam from the highest elevation. Drilling is typically performed during a 10-hour period each day, with round-the-clock mining operations in two shifts. With benches of 8m high in both pints, the coal sits on a 30-degree incline in seams with a thickness range of 5-30m. The coal in Pit 2 operates at 5,800kcal, while Pit 1 is at 6,000kcal. The coal in Pit 2 is lower in quality, but the seams are usually thicker and more convenient to mine.

Conclusion

In a month, PSG generates 700,000 tonnes of coal from Pit 1 and 300,000 tonnes from Pit 2, yielding a stripping ratio of 7 to 1. Mining began at an elevation of 90m over the seal level and is presently at 20m ASL. Exploration is progressing to estimate the total depth of the coal formation, with a third pit scheduled in the future. Possessing the DM30 II drill rig is advantageous to the mine as it provides more options due to its size.

About Atlas Copco

In close cooperation with customers and business partners, and with more than 130 years of experience, Atlas Copco innovates for sustainable productivity.

  • The products and services include compressors, expanders and air treatment systems, construction and mining equipment, power tools and assembly systems.
  • Atlas Copco's customers are located almost everywhere on the globe. To them, Atlas Copco is a local company; at the same time, the Atlas Copco Group is a global enterprise with worldwide resources.
  • Headquartered in Stockholm, Sweden, the Group’s global reach spans more than 170 markets, with its own sales operations in more than 80 countries. In the other countries, the products are marketed through distributors and service networks.
  • The Group has production facilities in more than 20 countries. Manufacturing is mainly concentrated in Belgium, Sweden, Germany, the United States, India and China.

The objective of Atlas Copco’s corporate responsibility work is to be a good corporate citizen in each market. This is done by making a positive impact in economic, environmental and social aspects, and through employee pride in the Group’s values.

Atlas Copco’s vision is to become and remain First in Mind—First in Choice® for its stakeholders, which is also the driving force of the Group’s corporate responsibility strategy

With a tradition of innovation dating back to the Group’s founding in 1873, the core business remains much the same, with today's equipment delivering an unparalleled level of efficiency.

This information has been sourced, reviewed and adapted from materials provided by Atlas Copco.

For more information on this source, please visit Atlas Copco.

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