The Utah State Division of Oil, Gas & Mining (OGM) said that despite pleas from the men’s families, plans to send a manned capsule down to the miners have been scrapped.
A spokesman said that the Mine Safety & Health Administration (MSHA), which is co-ordinating the rescue with mine owner Murray Energy Corporation, has decided that using the capsule would be too risky.
The site has seen numerous collapses since the initial cave-in on 6 August.
"MSHA feels it is an unprecedented event that makes it very difficult to come up with a plan," said a OGM spokesman.
"It is such a catastrophic collapse that even after the first event, pillars in the mine have continued to fall as the rescue attempt goes on."
He said the MSHA decided health and safety factors made it too risky to get even one man with sufficient breathing apparatus in the capsule down to the collapse 457m underground.
Rescuers have instead drilled seven boreholes in an attempt to locate the trapped miners, but the spokesman said hopes of finding the men alive were fading because samples had shown the air to be "not good".
The boreholes range in size from 51mm to 219mm in diameter and have been drilled down to between 518m and 549m. Camera and microphone equipment has been lowered into the holes to try and find the trapped men, however, no evidence has yet been found to confirm they are alive.
The cause of the accident was a mine bump – what the MSHA describes as a catastrophic failure of the mine structure. Seismologists with the US Geological Survey National Earthquake Information Center in Colorado and at the University of Utah said the event registered 3.9 on the Richter Scale.