the record with care, we find, for the reasons set forth hereinafter, that the risk of an explosion or fire was too remote and speculative to have constituted an imminent danger within the meaning of the Act. 43 CFR 4.605. Accordingly, we reverse the decision below and vacate the subject withdrawal order. Procedural and Factual Background The withdrawal order in question, No. 2 LCW, was issued by a Mining Enforcement and Safety Administration (MESA) inspector on January 24, 1974 at appellant's Margaret No. 7 Mine. The order cited the following condition: Accumulations of float coal dust along the 11 Right belt conveyor for a distance of The order was terminated nine hours subsequent to its issuance after the application of 20 tons of rock dust. The present case was instituted by appellant on February 4, 1974 when it timely filed an application for review pursuant to section 105(a) of the Act. 30 U.S.C. § 815(a) (1970). Appellant asserted in pertinent part that the condition cited in the subject withdrawal order could not have reasonably been expected to cause death or serious bodily harm before such condition could be abated. MESA filed an answer in opposition on February 11, 1974. Three days later, on February 14, 1974, the United Mine Workers of America (UMWA), as representative of the miners at the subject mine, also filed an answer contending, as did MESA, that the challenged order was valid in all respects. An evidentiary hearing before the Judge was held on April 4, 1974 at which time all parties were represented except the UMWA. Following conclusion of the hearing, all parties except the UMWA filed proposed findings of fact and conclusions of law. In addition, appellant filed a post-hearing brief. By decision dated October 15, 1974, the Judge denied appellant's request that the subject withdrawal order be vacated and affirmed its validity. On November 18, 1974, appellant filed its notice of appeal. Subsequently, timely briefs by appellant and MESA were filed with the Board and oral argument took place before the undersigned panel on June 16, 1975. The UMWA has not participated in this appeal. Issue on Appeal Whether the Administrative Law Judge erred in concluding that the subject withdrawal order was issued on the basis of a condition which at the time of issuance warranted a reasonable estimate or expectation that death or serious bodily injury would occur before elimination of the danger if normal operations to extract coal continued. Discussion [1] Appellant takes issue with one principal aspect of the decision below. It contends in substance that the Judge abused his fact finding discretion in weighing the inspector's expert opinion to the effect that the chance of an explosion or fire occurring amounted to just a possibility. Judge erred in concluding that the subject danger was imminent on the basis of his finding, contrary to the inspector, "*** that the chance of something going awry is more than a mere possibility." It also argues that the The basic facts essential for a decision in this case are undisputed. The specific area of the mine covered by the subject withdrawal order was the No. 11 right belt line which spans a distance of approximately 3,200 feet. For most of its length, the entryway is approximately three and one-half feet high and is traversible only by lying flat in a prone position on the conveyor belt. Water runs through the entry for about 500 feet and there are other wet spots along the belt line. The sole mining activity occurring in this portion of the mine is the transporting of coal along the belt; no other operations associated with the extraction of coal take place in this area. There is no evidence of a history of methane releases or gas explosion in the subject mine. Float coal dust consists of extremely fine particles of coal that are carried along by air current. The dust settles down and forms a layer on rib and floor surfaces. The depth of such a layer may be extremely small and is not readily measurable. The presence of such dust is ascertained by subjective and purely visual observation. Dry float coal dust is more readily ignitable than larger particles of coal. Moreover, it is so lightweight that it is easily disturbed and can explode, when in suspension in sufficient quantity and upon ignition. The inspection, which led to the issuance of the subject withdrawal order, was conducted by MESA inspector Lester C. Walker. Mr. Walker was accompanied by Mr. Walter C. Balitski, his super visor, as well as by Mr. William E. Edmonds, appellant's mine superintendent. The inspection party traveled 2,700 feet along the subject belt line lying flat on their stomachs, but were able to walk upright through the remaining 500 feet. The principal sources of illumination were headlamps worn by each person. The inspector concluded that there were dangerous accumulations of float coal dust because the entry was "black," and at one point he raised some dust by kicking the surface. He neither measured nor sampled the dust. (Tr. 19-25.) Appellant established that there was a substantial amount of wetness and dampness throughout the entry. (Tr. 74, 135-6, 197-8.) It also showed that the "accumulation" lay considerably beneath the conveyor belt rollers. (Tr. 119, 225.) The inspector had no knowledge of methane in the area or of any history of prior methane explosions in the subject mine. (Tr. 70.) The air in the subject entry was adequate and was directed toward the working sections. (Tr. 30.) The potential sources of ignition were, according to the inspector, a 550 volt insulated feed line, electrical switches, |