Regulators are also considering 53 proposals to improve plans by tapping through-the-earth communication technology and other emerging methods, Chirdon said.
Massey Energy Co. had some of its required new system installed at its Upper Big Branch mine at the time of the April 5, 2010, explosion that killed 29 men. Regulators have said the blast destroyed the system, rendering it unusable during a nearly weeklong search for some of the victims.
Besides gear that can survive accidents, manufacturers are also developing systems that can keep up with miners and machinery on the move, Chirdon said. Some are even adding components that can warn miners about gas and coal dust levels, and when they're in danger of colliding with equipment.
MSHA's numbers show 192 out of the 529 mines lacked a full set of equipment as of February. Most, however, have done part of the work, Chirdon said.
"We're expecting them all to be compliant by June 15," Chirdon told the Associated Press on Thursday.
The numbers are far higher than 2010. At the time, just 34 of 529 mines, or 6.4 percent, were in compliance, Chirdon said.
Associated Press Business Writer Tim Huber in Charleston contributed to this report.