Since this event isn't "cannon", I'll refer to the events in present tense.
After Clark Kent does a boring article on a meteor passing Earth, he tries (and fails) to interview the gangster "Rocks". Later, Clark and Lois go to a museum and meet Daryl Bronson. Rocks tries to rob the museum, but only steals a seemly worthless painting. The meteor turns out to be from Krypton. The meteor (travelling near Earth, but doesn't enter the atmosphere) robs Superman of his powers. Lois visits Bronson only to discover he is working for "Rocks". Clark Kent sees a professor (who had gained "K-Metal" from another Kryptonian meteor) and discovers K-Metal can sap his powers and give normal people powers similar to his. Clark goes to "Rocks'" house and finds some goons carrying a package. The package contains a ultra-violet light generator that reveals the painting is a map to a gold mine worth millions. A goon knocks out Clark. Bronson kills "Rocks" and kidnap Lois. "Rocks'" goon take Clark to a mine to shoot him. However, Bronson appears and puts Lois in the mine and seals them in by causing a cave-in. The meteor leaves the Earth thus giving Clark his powers. Clark is conflicted since if he saves them he'll reveal he is Superman. Clark decides to reveal his identity and save them. Superman defeats Bronson. Since Lois knows he is Superman, she wants them to become partners, which Superman agrees to. The K-Metal is stolen by an unknown villain.
K-Metal is a fictional metal from Krypton (hence the name). K-Metal is a precursor to kryptonite. K-Metal may be radioactive since it is green and glows. When a kryptonian touches the metal, they lose their powers and become weakened (although not to lethal levels). However, a meteor of it was able to remove Superman's powers despite not touching him. When a human touches the metal, they gain powers similar to that of Superman such as super strength.
- http://supermanthrutheages.com/k-metal/splash.php has a (mostly) restored and remastered version of the story