The firm, which launched an investigation into Patriot last September, said the company failed to properly account for the costs of its selenium water treatment obligations.

It alleged Patriot capitalized these costs instead of recording them as expenses, thereby overstating the company’s financial results.

In the wake of the miner’s Chapter 11 bankruptcy filing last July, several law firms filed class suits on behalf of aggrieved shareholders who bought in from October 2010 to July this year.

Pennsylvania lawyers Ryan & Maniskas , New York firm Rigrodsky & Long, and California attorneys Robbins Umeda filed separate class actions against Patriot last month on the charge of misleading bookkeeping of selenium-based costs.

Earlier this month, Maryland-based law firm Brower Priven cited Patriot’s selenium water requirements when announcing a November deadline for shareholders who wanted to be lead plaintiffs in a securities fraud class action suit against the miner.

In January 2012, Patriot settled to pay $US7.5 million in civil penalties for selenium discharges from its mining activities in West Virginia. Several legal entities have since alleged the miner may have failed to properly account for costs associated with court-ordered selenium treatments.

The news coincides with continued pressure from union members and retired Patriot miners to move the company’s pending bankruptcy case from New York to a West Virginia court.

According to reports from West Virginia’s Charleston Gazette, dozens of retired coal miners from around the country are pleading their case to a federal judge in New York City via handwritten letters.

“I would just like to say in my own voice the indignity that I am feeling at this moment,” one letter was quoted as saying in the newspaper. “I would like for those few to sit back and put themselves in our places.”

Miners have expressed concerns that their pensions and health care benefits may not be considered if Patriot’s bankruptcy hearing proceeds in New York.

The United Mine Workers of America has also been vocal on the topic.

UMWA president Cecil Roberts said the group wanted to see the reorganization of Patriot moved to the Southern District of West Virginia because it is “a case about coal and coal miners who live here in the coalfields.”

Patriot is responsible for more than 10,000 retirees and 10,000 dependents across Appalachia and the Illinois Basin.