I am trying to make a delay of 1 minute in a redstone circuit. That would require 600 ticks. That s a lot of repeaters going to be used. Is there other ways of getting a 1 minute (or even longer) delays in a redstone circuit?
For delays of order of 30 seconds to 4 minutes the Etho Clock is the optimal solution. You fine-tune the time by changing the number of items in the hopper, one item corresponding to 0.8s. If you want just delay instead of cyclic operation, you can use this in pulse extender variant - one of the pistons sticky, one normal (the clock variant uses both sticky pistons).
In case this isn't visible: the hoppers are facing into each other.