Carbonoks, maker of mine rescue shelters, is operating at full-bore.

This summer the company has cleared government hurdles, expanded into another country and decided to add a handful of more employees.

The Rock Branch-based company is the first to receive electrical approval for its underground safe haven from the U.S. Department of Mine Safety & Health Administration.

"That's a big, big thing," said Susan Johnson, director of business development. "In 18 months we have gone through concept, designing, engineering, testing, prototyping and manufacturing."

Johnson added that Carbonoks may have set the bar high because its unit is the first to have electrical components.

She said the only thing left is to get MSHA's approval of the whole unit.

That shouldn't be difficult because the specifications of Carbonoks' shelter far exceed federal standards.

For example, the feds require 15 psi blast capability. Carbonoks' unit failed at 232 psi, Johnson said. The explosion at Sago Mine in Upshur County that killed 12 miners is believed to have measured at 100-110 psi pressure.

The Sago disaster of 2006 has been driving the company's work.

"On practically every wall in our offices -- even in the restrooms -- are copies of one of the letters that the Sago men wrote," Johnson said. "We are bombarded daily by what drives us. That is saving lives and saving miners and their families from tremendous loss."

Carbonoks' rescue chamber is designed to stand up in the worst possible scenario: fire, flood, roof-falls and explosions.

It can withstand 2,000-degree temperatures for one hour -- steel starts melting at 1,600 degrees Fahrenheit, Johnson said. It is so watertight that the mine can flood completely and the miners inside the unit will be fine. It can hold as many as 20 miners and sustain them with breathable air for five days. There are enough meals-ready-to-eat to feed them for three weeks. It is crush-proof up to 150 tons. Most roof falls are 10 to 15 tons, Carbonoks has said in the past.

The second biggest thing happening for the company is its expansion into global markets.

"At the end of this month we will be signing a franchising agreement with a company in Australia," Johnson said. "We were recently contacted by a company in China about being a distributor for our product."

She said Carbonoks is exploring the possibilities of that. China's interest in refuge chambers is significant because that country has such abundant stores of coal that in some cases 400 miners are on one underground shift at a time at a mine site. Johnson said that a mining disaster in China usually means a catastrophic loss of life.

Carbonoks' board of directors recently gave the OK to hire four more people, but that was not the result of the Australian agreement. Johnson said 27 or 28 people will work for Carbonoks after the new hires.

So far Carbonoks has shipped about six units and they have stepped up production to fill orders more quickly for mines that the state has given required to have refuge chambers.