Mine Line

The line began as a freight railway for the Ōmine coalfield. The private Sanyo Railway Company opened the first section, from Asa to Ōmine (about 19.6 km), on 13 September 1905 to haul coal, establishing Atsu, Shirōgahara, Isa (the present Minami-Ōmine) and Ōmine stations. When the trunk Sanyo Railway was nationalised on 1 December 1906, this branch passed to the state, and on 12 October 1909 the government railways designated the Asa–Ōmine section the Ōmine Line.

A second concern extended rail into the Mine district. The Mine Light Railway Company opened the line from Isa to Shigeyasu (about 5.5 km) on 15 September 1916; that company was nationalised on 1 June 1920, becoming the government's Mine Light Line. The route was then pushed northward, and on 23 March 1924 the Ōfuku–Shōmyōichi section (about 18.8 km) opened, completing a through line across the prefecture from the Sanyō side to the San'in side.

The line's shape was settled over the following decades. On 24 February 1933, when the San'in Main Line was completed as a through route, the northern Shōmyōichi–Udagō portion was transferred into the San'in Main Line. The route through Mine acquired its present name, the Mine Line, on 1 October 1963.

Dieselisation and modernisation followed in the postwar years. From 10 September 1960 passenger services were largely converted to diesel railcars, apart from one morning up and one evening down working and the Ōmine branch; steam traction was eliminated by early 1972, and centralised traffic control was installed in 1974. Freight remained important — general freight services ran until 1984, while limestone haulage from Shigeyasu continued much longer, ceasing only in 2009.

Upon the privatisation of Japanese National Railways on 1 April 1987, the Mine Line was succeeded by the newly formed West Japan Railway Company (JR West). Passenger services came to be operated mainly by KiHa 120 diesel railcars from the 1990s. The little-used Minami-Ōmine–Ōmine branch (2.8 km), a remnant of the original coal line, was closed to traffic on 1 April 1997. The line had already shown its vulnerability to weather: heavy rain on 15 July 2010 washed away bridges and track bed and suspended the entire line, which was not restored to full service until 26 September 2011, in time for the national sports festival held in Yamaguchi that year.

A far more serious disaster struck in 2023. Record heavy rain at the end of June and start of July 2023 washed out a bridge over the Atsa River between Shirōgahara and Minami-Ōmine and scoured ballast at several other points, and on 1 July 2023 the whole line fell out of service. Substitute buses began running on 4 July 2023 across most of the route, with substitute taxis on the Asa–Yunotō section. JR West stated that restoring and sustainably operating the line on its own would be very difficult without outside financial support, and on 22 May 2025 it presented the view that recovery by bus rapid transit (BRT) was the most appropriate course. On 16 July 2025 the parties agreed to give up rail restoration and rebuild the route as BRT, and on 7 August 2025 the prefecture and municipalities formally concluded an accord to abandon the railway and convert the Mine Line to bus rapid transit.

• 190513 September: the Sanyo Railway opens the first section, Asa–Ōmine (about 19.6 km), to haul coal from the Ōmine coalfield; Atsu, Shirōgahara, Isa and Ōmine stations open.
• 19061 December: the Sanyo Railway is nationalised; the branch passes to the government railways.
• 190912 October: the government railways designate the Asa–Ōmine section the Ōmine Line.
• 191615 September: the Mine Light Railway Company opens Isa–Shigeyasu (about 5.5 km).
• 19201 June: the Mine Light Railway is nationalised, becoming the government's Mine Light Line.
• 192423 March: the Ōfuku–Shōmyōichi section (about 18.8 km) opens, completing the through line across the prefecture.
• 193324 February: on completion of the San'in Main Line as a through route, the northern Shōmyōichi–Udagō portion is transferred into the San'in Main Line.
• 196010 September: passenger services are largely converted to diesel railcars, apart from one morning up / one evening down working and the Ōmine branch.
• 19631 October: the route is renamed the Mine Line.
• 1984General freight services on the line cease (limestone haulage from Shigeyasu continues).
• 19871 April: with the privatisation of Japanese National Railways, the line is succeeded by JR West.
• 19971 April: the Minami-Ōmine–Ōmine branch (2.8 km), a remnant of the original coal line, is closed to traffic.
• 2009Limestone haulage from Shigeyasu — the line's last freight — ceases.
• 201015 July: heavy rain washes away bridges and track bed, suspending the entire line.
• 201126 September: the line is restored to full service, in time for the national sports festival held in Yamaguchi.
• 20231 July: record heavy rain washes out a bridge over the Atsa River between Shirōgahara and Minami-Ōmine and scours ballast elsewhere; the whole line is suspended. Substitute buses begin on 4 July (with substitute taxis on the Asa–Yunotō section).
• 202522 May: JR West presents the view that recovery by bus rapid transit (BRT) is most appropriate; on 16 July the parties agree to abandon rail restoration for BRT; on 7 August the prefecture and municipalities formally agree to convert the line to BRT.