WELLINGTON, New Zealand (AP) — An Australian drilling company pleaded guilty Tuesday to three safety violations in connection with a 2010 coal mine disaster in New Zealand that killed 29 miners.

VLI Drilling pleaded guilty in a New Zealand court to charges that it failed to keep its workers safe at the Pike River coal mine. The company faces a maximum fine of 750,000 New Zealand dollars ($607,000). VLI, a contractor at the mine, employed three of the men who died.

Nine safety and health charges also are pending against the main mine operator, Pike River Coal Ltd., which employed the rest of the victims. The receivers for the bankrupt company elected Tuesday not to contest those charges in court. A court is scheduled in October to determine the company's culpability.

Pike River Coal's former chief executive, Peter Whittall, also faces 12 charges, which he has vowed to fight.

Bernie Monk, father of a Pike River Coal employee killed in the disaster and a spokesman for all of the victims' families, said VLI has been able to walk away without facing any meaningful consequences.

"For me it's only a slap on the wrist," Monk said. "It's very hard to defend."

The men died after a series of methane-fueled explosions. The Labour Department said in a statement of facts about the case that it's not known if VLI's drill rig was running at the time of the first explosion. However, the department says VLI's methane detector on the rig was faulty and needed replacing, and hadn't been inspected as required.

Brett Lynch, the chief executive of parent company Valley Longwall International, emphasized that the charges didn't relate to the explosion itself. He said he regretted VLI not having in place proper procedures to ensure inspections were carried out.

"We regard the safety and wellbeing of our people as an absolute priority," Lynch said in a statement.

He said the company had provided "ongoing financial and practical support" to the families of the three dead miners, adding it would be inappropriate to disclose details.

At a government inquiry into the disaster, experts testified that the mine didn't have adequate escape routes or ventilation, and that Pike River Coal was cutting corners due to financial pressure. The inquiry is scheduled to issue its findings in September.

But Monk, whose 23-year-old son Michael died in the accident, said the failure thus far by New Zealand authorities to hold anybody accountable in a meaningful way or to implement better safety procedures was deeply frustrating. He said he and other victims' relatives will continue to push for both legal and mine safety reforms.

"We've had to fight every inch of the way to be heard," he said.

Monk said the families would consider civil litigation once the government inquiry is concluded.

Lynch said he didn't expect civil litigation to be brought against his company because the safety charges didn't relate to the explosion.

The Labour Department said in an email that any fines collected from VLI would go to the government rather than to the victims' families.

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    Twenty-nine <a href="http://www.facesofthemine.com/faces-of-the-mine-upper-big-branch-memorial-page/" target="_hplink">miners</a> died in an explosion at the Upper Big Branch mine on April 5, 2010. The mine, located in Montcoal, W.Va., was owned and operated by the Performance Coal Company, a subsidiary of Massey Energy.<br><br>The Mine Safety and Health Administration <a href="http://wvgazette.com/News/montcoal/201009170861" target="_hplink">has said</a> that sparks from a worn-out piece of machinery combined with a buildup of coal dust caused the accident. Massey Energy has <a href="http://blogs.wvgazette.com/coaltattoo/2011/01/28/massey-continues-to-dispute-msha-on-ubb-cause/" target="_hplink">continued to say</a> that a buildup of methane gas caused the explosion.<br><br>At a public meeting detailing the federal investigation, Kevin Stricklin, coal administrator for mine safety and health at MSHA, said that there were two sets of books on mine conditions kept by Massey workers -- an accurate log that included safety problems, and a separate, watered-down version for federal and state inspectors to see.<br><br>The Upper Big Branch explosion was the <a href="http://online.wsj.com/article/SB10001424052702304450604576415683464733192.html?KEYWORDS=upper+big+branch" target="_hplink">worst</a> U.S. coal mining disaster in 40 years.

  • Crandall Canyon Mine

    On Aug. 6, 2007, six miners were trapped in the Crandall Canyon Mine in Huntington, Utah, after roof-supporting pillars <a href="http://www.msha.gov/genwal/ccSummary.asp" target="_hplink">failed</a> and ejected coal over a half-mile area. Ten days later, three more people were killed by a subsequent collapse during the rescue effort.<br><br>According to the <a href="http://www.msha.gov/genwal/ccSummary.asp" target="_hplink">official</a> accident investigation summary released by the Mine Safety and Health Administration, the catastrophe was the result of "an inadequate mine design." Unsafe pillar dimensions and an poor engineering management review contributed to the collapse.<br><br>In the above photo, family and friends carry the the body of Dale Black -- one of the rescue team members -- to his burial site at Huntington City Cemetery.

  • Darby Mine No. 1

    On May 20, 2006, five miners were killed in an explosion at Darby Mine No. 1 in Holmes Mill, Kentucky. According to information <a href="http://www.usmra.com/saxsewell/darby.htm" target="_hplink">released</a> by the United States Mine Rescue Association, the explosion was the result of methane gas that was ignited by the cutting of a metal roof strap.<br><br>The miner who was working on the roof strap with a cutting torch had a functional methane detector tucked away in his pocket, a sign that it was not being used to check continuously for the potentially lethal gas. The USMRA also says a cutting torch should not have been used at the time.

  • Sago

    On Jan. 2, 2006, an <a href="http://www.msha.gov/sagomine/sagomine.asp" target="_hplink">explosion</a> at a mine in Sago, W.Va., killed 12 workers and severely injured one. The 13 miners were <a href="http://www.msha.gov/Fatals/2006/Sago/ftl06C1-12.pdf" target="_hplink">forced</a> to barricade themselves within the mine after the explosion -- caused by elevated levels of carbon monoxide and methane -- destroyed 10 seals used to separate a closed area of the mine.<br><br>Ben Hatfield, CEO of the International Coal Group, which owned the Wolf Run Mining Company that ran the Sago Mine, received criticism when the families of the fallen miners were falsely informed that the 12 men had lived. In an interview with NPR, workers and family members who were present when Hatfield broke news of the deaths <a href="http://www.npr.org/templates/story/story.php?storyId=5134307" target="_hplink">described</a> the scene as "chaos."

  • Scotia

    In March 1976, a succession of explosions at the Scotia Mine in Oven Fork, Ky., claimed a total of 26 lives.<br><br>The first blast happened on March 9, killing 15 men. During rescue efforts on March 11, a second explosion killed 11 more.<br><br>Investigators <a href="http://www.usmra.com/saxsewell/scotia.htm" target="_hplink">concluded</a> that both explosions were caused by the ignition of a methane-air mixture inside the mine.

  • Consol No. 9

    An explosion at the Consol No. 9 mine in Farmington, W.Va, killed 78 people on Nov. 20, 1968. The explosion was followed by raging <a href="http://www.wvculture.org/history/disasters/farmington02.html" target="_hplink">fires</a> that brought rescue operations to a halt.<br><br>A <a href="http://www.npr.org/templates/story/story.php?storyId=97115205" target="_hplink">memo</a> from a federal investigator that surfaced in 2008 revealed that a safety alarm on a ventilation fan had been deliberately disabled before the explosion. The alarm, which hadn't been working for as long as 90 minutes before the blast, could have saved the lives of the 78 miners.<br><br>The tragedy at Farmington led to the <a href="http://www.msha.gov/mshainfo/mshainf2.htm" target="_hplink">passage</a> of the federal Coal Mine Health and Safety Act in 1969. That act paved the way for the <a href="http://www.msha.gov/REGS/ACT/ACTTC.HTM" target="_hplink">Federal Mine Safety and Health Act of 1977</a>, the legislation that currently governs the Mine Safety and Health Administration's activities.

  • Cherry Mine

    On Nov. 13, 1909, a fire killed hundreds of workers in a coal mine in Cherry Hill, Illinois.<br><br>According to <a href="http://www.usmra.com/saxsewell/cherry.htm" target="_hplink">reports</a> from the United States Mine Rescue Association, kerosene torches were used that day after the mine's electrical system broke down. Hay brought into the mine to feed mules that worked underground caught fire after being parked under one of the torches.<br><br>The fire quickly spread, causing the deaths of 259 men and boys who worked in the mine.

  • Monongah Nos. 6 And 8

    On Dec. 6, 1907, explosions occurred at a pair of nearby mines in <a href="http://www.msha.gov/disaster/monongah/monon1.asp" target="_hplink">Monongah</a>, West Virginia, killing 362 men and boys. The blast could be felt as far as eight miles away.<br><br>It wrecked the mine's ventilation system, allowing toxic gas to fill the area and hinder rescue efforts. Though investigators aren't certain of the <a href="http://www.usmra.com/saxsewell/monongah.htm" target="_hplink">cause</a> of the explosion, it was probably started by the ignition of firedamp -- combustible gas made up mostly of methane -- and coal dust within the mine.