UPDATE 1-Russia's Mechel raises doubt about future

* Mechel files 2008 20-F form with SEC

* Includes going concern notice

* Says can access capital, continue operational existence

(Adds more details from 20-F, debt background, analyst)

By Alfred Kueppers and Polina Devitt

MOSCOW, June 24 (Reuters) - Debt-saddled steel and coking coal producer Mechel (MTLR.MM: Quote, Profile, Research) on Wednesday raised major doubts about its future as a going concern.

Top Russian steel producers borrowed more than $30 billion to make acquisitions and increase production during the pre-crisis boom [ID:nLU975877] and Mechel is one of the most indebted, with total debt of $5.4 billion as of Dec 31, 2008.

"There is substantial doubt about our ability to continue as a going concern," the company wrote in a key filing with the U.S. Securities and Exchange Commission (SEC).

It was the first report of a so-called "going concern" notice to a Russian company since the financial crisis hit, closing off debt markets and slashing demand for key export products such as steel. [ID:nN26301466]