Associated Electric Cooperative, Inc. (Associated) appeals from the district court's order granting summary judgment in favor of the Secretary of Labor and permanently enjoining Associated from excluding inspectors of the Mine Safety and Health Administration (MSHA) from its power-generating facility. Because we conclude that Associated is not a "mine" within the meaning of the Federal Mine Safety and Health Act, 30 U.S.C. §§ 801-962 (Mine Act), we reverse.
I.
Associated operates the Thomas Hill Energy Center, a three-unit, coal-fired electric power generating facility in Randolph County, Missouri. The facility obtains its coal from two mines in the Powder River Basin in Wyoming. Before shipment, the mines crush the coal into pieces approximately 2.5 inches in size. The coal is then shipped to the facility by rail. Associated engages in various preparation activities before burning the coal for electricity. All coal passes through grates to sift out large debris and under magnets to remove scrap metal. For one generator unit, coal is crushed into powder with pul-verizers. For the other two units, coal is broken into quarter-inch pieces with hammer mills. Associated also performs sampling to ensure that the coal complies with emission standards.
In September 1995, the federal Occupational Safety and Health Administration (OSHA) received a complaint about coal dust from an employee at the facility. An OSHA inspector visited the facility and took air samples. Subsequently, OSHA informed Associated that it was referring the matter to MSHA to determine which agency had jurisdiction to inspect the facility's coal processing operations. An MSHA inspector visited the facility in August 1996. MSHA informed Associated in March 1997 that it had jurisdiction over the coal processing activities, from the point where coal is unloaded from railroad cars until it is ready for combustion.
On June 23, 1997, an MSHA inspector attempted to complete a formal inspection of the facility's coal processing operations. Associated denied the inspector entrance to the facility. MSHA issued Associated a citation under section 813(a) of the Mine Act for refusing to allow the inspector entrance. Associated continued to deny MSHA entrance to the facility, whereupon the Secretary brought this suit to enjoin Associated from denying MSHA entrance.
After finding that it had subject matter jurisdiction to determine whether Associated is a "mine" within the meaning of the Mine Act, the district court found that Associated qualified as a mine because of its coal processing activities. The court then issued a permanent injunction requiring Associated to grant MSHA inspectors access to the facility.
II.
Initially, Associated claims that the district court did not have subject matter jurisdiction to determine its status as a "mine" under the Mine Act. Because the parties do not dispute the underlying facts, we review the court's determination of subject matter jurisdiction de novo. See United States v. Lawrence, 51 F.3d 150, 151-52 (8th Cir.1995) (reviewing a determination of subject matter jurisdiction de novo); Drevlow v. Lutheran Church, Missouri Synod, 991 F.2d 468, 470 (8th Cir.1993) (same).
According to Associated, the Mine Act only confers federal jurisdiction in cases involving " `habitual' offenders of the regulatory scheme" of the Act. See Appellant's Br. at 8 (quoting Thunder Basin Coal Co. v. Reich, 510 U.S. 200, 209, 114 S.Ct. 771, 127 L.Ed.2d 29 (1994)). Undoubtedly, the Mine Act confers federal jurisdiction when the Secretary believes that a mine operator "is engaged in a pattern of violation of the mandatory health or safety standards" of the Act. 30 U.S.C. § 818(a)(2). Associated overlooks the significance of section 818(a)(1), however, which provides for federal jurisdiction in many other cases, in-*1081eluding when a mine operator “refuses to admit [MSHA] representatives to the ... mine.” Id. § 818(a)(1)(C).
The Supreme Court has recognized that the Mine Act confers federal jurisdiction when any triggering event under section 818(a)(1) occurs. See Donovan v. Dewey, 452 U.S. 594, 604-05, 101 S.Ct. 2534, 69 L.Ed.2d 262 (1981) (stating that section 818(a) would confer federal jurisdiction when a mine operator denies an MSHA inspector access to a facility). The Third Circuit has asserted subject matter jurisdiction in a ease strikingly similar to the present one. In Marshall v. Stondt’s Ferry Preparation Co., an operator claimed that its facility was not a “mine” within the meaning of the Mine Act and denied entrance to an MSHA inspector. 602 F.2d 589, 590 (3d Cir.1979). The Third Circuit held that the facility qualified as a mine under the Act and enjoined the operator from denying MSHA inspectors access to the facility. Id. at 592.
Interpreting the Mine Act to confer federal jurisdiction only when operators habitually violate the Act would render section 818(a)(1) nugatory. This would contradict fundamental principles of statutory construction. See United States v. Talley, 16 F.3d 972, 975-76 (8th Cir.1994) (citing Moskal v. United States, 498 U.S. 103, 109-10, 111 S.Ct. 461, 112 L.Ed.2d 449 (1990)) (holding that whenever possible, statutes should be construed to give effect to all of their clauses and words). Accordingly, we conclude that the district court had subject matter jurisdiction over this case under section 818(a)(1)(C).
III.
Associated also asserts that it is not a mine within the meaning of the Mine Act. We review the district court’s construction of the term “mine” in the Act de novo. See United Energy Servs., Inc. v. Federal Mine Safety & Health Admin., 35 F.3d 971, 974 (4th Cir.1994); Bush & Burchett, Inc. v. Reich, 117 F.3d 932, 935-36 (6th Cir.), cert. denied, - U.S. -, 118 S.Ct. 46, 139 L.Ed.2d 12 (1997).
The Act provides:
“coal or other mine” means (A) an area of land from which minerals are extracted in nonliquid form ..., (B) private ways and roads appurtenant to such area, and (C) lands, excavations, underground passageways, shafts, slopes, tunnels and workings, structures, facilities, equipment, machines, tools, or other property ... used in, or to be used in, or resulting from, the work of extracting such minerals from their natural deposits ... [or in] the milling of such minerals, or the work of preparing coal or other minerals, and includes custom coal preparation facilities.
30 U.S.C. § 802(h)(1). The Act goes on to define “the work of preparing coal” as “breaking, crushing, sizing, cleaning, washing, drying, mixing, storing, and loading of bituminous coal, lignite, or anthracite, and such other work of preparing such coal as is usually done by the operator of the coal mine.” Id. § 802(i). The issue before us is whether a utility company that performs some of these tasks on previously processed coal is a mine under the Act.
In adopting the Mine Act, “Congress was plainly aware that the mining industry is among the most hazardous in the country.” Dewey, 452 U.S. at 602, 101 S.Ct. 2534. Therefore, it designed the Act to “improv[e] the health and safety conditions in the Nation’s underground and surface mines.” Id. The statute expressly declares, “[I]t is the purpose of this chapter ... to protect the health and safety of the Nation’s coal or other miners.” 30 U.S.C. § 801(g). See also Thunder Basin, 510 U.S. at 209-10, 114 S.Ct. 771 (discussing Congress’s purpose for adopting the Act).
To achieve these goals, Congress intended that “what is considered to be a mine and to be regulated under this Act be given the broadest possible] interpretation.” S.Rep. No. 95-181, at 14 (1977), reprinted in 1977 U.S.C.C.A.N. 3401, 3414; see also Bush & Burchett, 117 F.3d at 936-*108237 (stating that the word “mine” should be construed broadly due to the remedial nature of the Act); RNS Servs., Inc. v. Secretary of Labor, 115 F.3d 182, 187 (3d Cir.1997) (same); United Energy, 35 F.3d at 975 (same); Donovan v. Carolina Stalite Co., 734 F.2d 1547, 1553-54 (D.C.Cir.1984) (same). The remedial nature of the Mine Act does not allow courts to extend its coverage without limit, however. “It is clear that every company whose business brings it into contact with minerals is not to be classified as a mine within the meaning of section [802](h).” Carolina Stalite, 734 F.2d at 1551; see also Pennsylvania Elec. Co. v. Federal Mine Safety & Health Review Comm’n, 969 F.2d 1501, 1510 (3d Cir.1992) (Mansmann, Circuit Judge, dissenting).
In Old Dominion Power Co. v. Donovan, the Secretary attempted to assert MSHA jurisdiction over a utility that sold electricity to a mine and periodically entered mine property to read the meter. See 772 F.2d 92, 93-94 (4th Cir.1985). The Fourth Circuit found no MSHA jurisdiction because Congress did not intend all independent contractors that work at a mine to be considered “mine operators” under the Act. Id. at 96-97. Similarly, in Bush & Burchett the Secretary asserted MSHA jurisdiction over a bridge that a mine built to accommodate its traffic on a state highway between the mine and a loading facility on a nearby river. See 117 F.3d at 933. The Sixth Circuit held that MSHA did not have jurisdiction over the bridge because it was dedicated to the state highway system for public use. According to the court, “without some limitation on the meaning of ‘roads appurtenant to,’ MSHA jurisdiction could conceivably extend to unfathomable lengths.” Id. at 937.
Likewise, not all businesses that perform tasks listed under “the work of preparing coal” in section 802(i) can be considered mines. The Act was designed primarily to protect miners, not employees of coal purchasers such as electric utilities and steel mills. See Pennsylvania Electric, 969 at 1510 (Mansmann, Circuit Judge, dissenting) (quoting Secretary of Labor v. Pennsylvania Elec. Co., 11 FMSHRC 1875, 1889-90 (1989) (Doyle, Comm’r, dissenting)); see also S.Rep. No. 95-461, at 37 (1977) (stating that the Act was meant to regulate “mining activity”). Although Associated performs some coal processing operations listed in section 802(i), its employees are not “miners,” even in the broadest sense of the word. “[Ijnherent in the determination of whether an operation properly is classified as ‘mining’ is an inquiry not only into whether the operation performs one or more of the listed work activities, but also into the nature of the operation performing such activities.” Secretary of Labor v. Elam, 4 FMSHRC 5, 7 (1982).
The Secretary relies on decisions of the Mine Safety and Health Review Commission that subject utilities to MSHA jurisdiction. Such decisions, while instructive, are not binding. Further, they can be distinguished from the present case. In Secretary of Labor v. United Energy, the Commission held that a utility located adjacent to a mine was itself operating as a mine because it maintained a conveyor system to transport coal refuse from the mine and performed all processing activities needed to make the refuse a marketable product. See 15 FMSHRC 2022, 2058 (1993). Similarly, in Pennsylvania Electric, the Commission subjected a utility to MSHA jurisdiction because it operated a conveyor that transported run-of-mine, or unprocessed, coal from a mine to a separately-owned custom coal preparation facility located on the utility’s property. See 11 FMSHRC at 1880. In that case, the Secretary did not attempt to assert MSHA jurisdiction beyond the custom coal preparation facility. Id. at 1876. See also Secretary of Labor v. Alexander Bros., Inc., 4 FMSHRC 541, 545 (1982) (subjecting an operator to MSHA jurisdiction because it performed all processing tasks necessary to convert refuse into marketable coal); Secretary of Labor v. Westwood Energy *1083Properties, 11 FMSHRC 2408, 2413-14 (1989) (same); Air Prods. & Chems., Inc. v. Secretary of Labor, 15 FMSHRC 2428, 2429-31 (1993) (same).
The Commission decisions subjecting utilities to IVISHA jurisdiction thus fall into two categories: (1) where the utility maintains a presence at a mine to assist in transporting coal to its generating facility, and (2) where the utility performs all processing tasks necessary to convert coal refuse into a marketable product. Circuit court decisions subjecting utilities to MSHA jurisdiction can be similarly categorized. See RNS, 115 F.3d at 185 (utility performed all processing tasks on coal refuse); United Energy, 35 F.3d at 973 (utility maintained conveyor system at mine and processed coal waste into marketable coal); Pennsylvania Electric, 969 F.2d at 1503 (utility maintained conveyor system to transport run-of-mine coal from adjacent mines). In essence, after a mine delivers processed, marketable coal to a utility any further operations to prepare the coal for combustion are not subject to MSHA jurisdiction. See United Energy, 35 F.3d at 975 (holding that "delivery of coal to a consumer after it is processed usually does not fall under the coverage of the Mine Act").
In the present case, Associated purchased coal that was processed into a marketable form by the mine.1 Associated did not participate in transporting the coal from the mine, nor were its processing activities necessary to make the coal marketable. Therefore, its coal-handling operations are more properly characterized as "manufacturing" than "mining." While MSHA may have expertise in regulating the hazards of coal dust, Congress designed the Mine Act primarily to protect miners. The Secretary cannot claim that Associated's employees are miners. If Congress wishes to expand the Act to cover consumers of coal such as utilities and steel mills, it is better suited to that task than this court. We simply hold that under the current version of the Mine Act, a utility that receives processed coal from a mine does not itself become a "mine" by further processing the coal for combustion.
Associated's coal processing operations remain subject to OSHA jurisdiction. See 29 C.F.R. §-1910.269(a)(1)(i)(B)(1) (stating that OSHA regulations apply to coal-handling installations at utility companies), 1910.269(v)(11)(xii) (requiring utilities to eliminate or control coal dust). Indeed, in prior cases the Secretary has asserted that MSHA has a "policy of inspecting those areas of a power plant that involve the handling ahd processing of run-of-mine coal and of leaving to OSHA the inspection of those areas that involve the handling of previously processed coal." See Pennsylvania Electric, 11 FMSHRC at 1884, cited in Westwood, 11 FMSHRC at 2417. Extending MSHA jurisdiction to the coal-handling operations in the present case would result in needless confusion for utility workers about whether MSHA or OSHA regulations apply to their conduct. "Requiring electric utility employees suddenly to adhere to conflicting standards depending on their job location can only lead to danger, especially where work around high voltage is involved." Old Dominion, 772 F.2d at 99.
The judgment of the district court is reversed, and the case is remanded with instructions to dismiss the Secretary's request for preliminary and permanent injunctions.
. The mine sold its coal to approximately 50 industrial, commercial, and utility customers. See Stipulated Facts ¶ 12, J.A. at 87.