Below is the text you can read from within the message.
We require 5 necronium greataxes to be dropped off behind the gem shop in Falador. This is an urgent request. Please deliver these as soon as possible. Thanks.
After completion of the associated quest, if you have unlocked the entire Hub track, this item can be retrieved from the Quest Item Storage chest at the Quest Point Caravan if lost or destroyed.
There is no need to keep this item after the miniquest has been completed. As such, it can be destroyed or kept as you desire.