When you rent a plot, you have several benefits taking your mining to the next level:
1) No one except for you (or people you hire) can extract deposits on your plot.
2) You are not limited to the volumes of extracted resources since they are gathered in the warehouse.
3) You can construct an quarry or mine to increase the efficiency of extraction and number of workers on the deposits.
4) You can create orders for mining and hire workers from other prospectors.
5) You can trade the extracted resources. As soon as you create an order for selling on the plot, your goods appear in the list of products on the general market.
6) You can use, process or sell all the extracted resources to other players.
If this plot is occupied by anyone, you will see the "Info" tab on it or you can use the filter and select all occupied areas.
By clicking the "free plots" button you will filter all plots to "free" and "rented".