BEIJING (AP) — Chinese authorities detained 13 people over the collapse of scaffolding at a power plant construction site that killed 74 workers, as a preliminary investigation zeroed in on how the building company had rushed the job. Most of the dead had been working on the interior concrete wall of a massive circular cooling tower 70 meters (230 feet) up when the scaffolding collapsed Thursday morning, resulting in one of China's most serious industrial accidents in years. State media reports said the accident occurred during a change of work shifts, possibly accounting for the high death toll.