I am recommending going against the convention of taking out the mines in the game. In fact keep 9 mines in the map as often as you can. Destroying the mines is risky and time consuming. There is no guarantee the next time you pick up a dubloon another mine wont pop up right next to you. My strategy is this.
Keep the 9 mines in a centre mass. The assumption here is you should be quite a good player. Dive in between two mines and you would bring them closer. If there are 3 mines, stay in the centre and let them move towards you and then move away. This way you would have 3 mines quite close to each other.
Try to keep the mines as close to each other as possible without blowing each other up. You have then go round to collect the dubloon to have all nine mines on the map. Try to dive in between any stray mines to make them closer to the main group. Once you have all the possible number of mines on the map in a tight group, you then have an easy time to go round collecting the dubloon.
If the dubloon should appear in the middle of the group, no worries. Just go to corner, draw them away from the dubloon. If space is a bit tight, then move to to another corner either up down or left right of the corner, this would make the mines constantly move away from the dubloon to create space to collect.
A handy tip is that is you move really fast beside a dubloon you can easily pick it up without really touching it to collect it. Sort of a Bernoulli effect.
The advantage of using this strategy is that there is no chance that a random mine might pop up right next to you when u collect the dubloon. You have perfect knowledge where all the mine is at all times. Only drawback is once in a while the whirlpool appears and messes up the formation and you would have to start again. Hope this helps you getting the 1K easily. I know I did. – Elvin