Former hard coal mine shaft in the Neunkirchen coalfield, part of the Grube König-Dechen complex, closed 1968, with the site cleared in the 1970s and the former Allenfeldschacht area now part of a commercial and residential zone in Neunkirchen.
The Allenfeldschacht was one of the outer shafts of the Grube König-Dechen hard coal mine in Neunkirchen (Saar). Its coordinate places it at the north-eastern periphery of the Grube König-Dechen Grubenfeld, in the direction of the Allenfeld area between the main König surface complex and the former Grube Dechen/Heinitz workings. The core mine, Grube König, had its origins in a Stollenbergwerk founded in 1820; after the Tiefbau began with Wilhelm-Schacht 1 on 1 May 1847 and a succession of further shafts, the field extended progressively north and north-east.
The Grube Dechen, which operated independently from 1855 in the Holzhauertal at Heinitz, came under the directorship of the Grube König on 1 January 1963 and was formally merged into the Verbundbergwerk König-Dechen on 1 January 1964. All operations at the Verbundbergwerk König-Dechen ceased on 31 March 1968. The Tagesanlagen of the former König-Dechen Grubenfeld, including the Allenfeldschacht site, were largely demolished in the 1970s.
Only the Fördergerüst over Wilhelmschacht I at the main König site in Neunkirchen survived, as the Wahrzeichen of the Industriegebiet König.
The history of mining at the site of the Allenfeldschacht belongs to the extended operational territory of the Grube König-Dechen. The Grube König, established in 1820 as a Stollenbergwerk to supply the Neunkircher Eisenhütte of the Gebrüder Stumm, entered Tiefbau with the anteufung of Wilhelm-Schacht 1 on 1 May 1847 and Wilhelm-Schacht 2 in 1854. Over subsequent decades a succession of further shafts were sunk as the Grubenfeld expanded northward and north-eastward in the direction of Heinitz. The Grube Dechen, founded independently in 1855 in the Holzhauertal and named after Oberberghauptmann Heinrich von Dechen (1800–1889), operated its own system of shafts — Schächte Dechen I, II, and III — from the 1850s. At its peak in 1938, Grube Dechen employed 2,040 workers and produced approximately 800,000 tonnes of Steinkohle annually. By the late 1950s and early 1960s, the underground fields of König and Dechen had been connected. In January 1963 the Grube Dechen was placed under the Betriebsdirektion of the Grube König; in August 1963 the underground Durchschlag was completed; and on 1 January 1964 the formal Verbundbergwerk König-Dechen was constituted.
The Allenfeldschacht, whose coordinate corresponds to the north-eastern margin of the Grubenfeld between the König and Dechen fields, functioned as part of the extended shaft infrastructure of this Verbundbergwerk. Precise dates for the sinking and function of the Allenfeldschacht have not been identified in the publicly consulted sources. Contextual evidence places its operational period within the final decades of the Grube König-Dechen's life, prior to the definitive closure on 31 March 1968. After closure, the Restvorräte of the Grubenfeld were worked by the Grube Reden. In the 1970s all surface buildings at the former König-Dechen sites — including any structures at the Allenfeldschacht location — were demolished. Portions of the cleared area became Brachfläche before later conversion to Gewerbegebiet and other uses. Only the Fördergerüst over Wilhelm-Schacht I at the main König site in Neunkirchen was retained, as the Wahrzeichen of the Industriegebiet König.