posted by rfvv .
1. The ice must be 15 centimeters thick at least.
2. The ice must be at least 15 centimeters tall.
(What is is the proper position of 'at least'? Are both OK? Do both sentences have the same meaning?)
#2 has the better placement of "at least" because it's placed right next to what it's describing, "15 centimeters."