My Bloody Valentine is a 1981 Canadian slasher film directed by George Mihalka and written by John Beaird. The film tells the story of a group of teenagers who decide to throw a Valentines Day party only to incur the vengeful wrath of a maniac in mining gear who begins a murder spree, and stars Paul Kelman, Lori Hallier and Neil Affleck.
Two miners in full gear, including face masks, are seen going down into a deep mine shaft. They reach an alcove and one of the figures takes off half of their gear, and is revealed to be a woman. As the other miner refuses to remove his gear, he sticks his mining pick in a wall, and she does a strip tease, fondling the mans mask and breathing tubes in a sexual manner, resulting the miner killing her by impaling her chest with the picks blade.The small town of Valentine Bluffs is seen preparing for a Valentines Day dance. The town is home to a coal mine, where many of the local men work, both young and old. Hanniger, the town Mayor, discusses the Valentines Day dance with a woman named Mabel Osborne, who runs a laundromat. Hanniger makes a vague reference to a past tragedy associated with Valentines Day, and reveals that this is the first Valentines dance to be held in decades. ........
Source: Wikipedia