The cost to upgrade the resources after level 10:

Clay pit
level 11:   13500 |   6750 |   13500 |    8435 | 2 |  5:34:50
level 12:   22540 | 11270 |   22540 |   14090 | 2 |  7:51:20
level 13:   37645 | 18820 |   37645 |   23525 | 2 |  11:02:20
level 14:   62865 | 31430 |   62865 |   39290 | 2 |  15:29:40
level 15: 104985 | 52490 | 104985 |   65615 | 2 |  21:44:10
level 16: 175320 | 87660 | 175320 | 109575 | 3 |  30:28:20 
level 17: 292790 | 146395 | 292790 | 182995 | 3 | 42:42:10

Wood
level 11:   6750 |   16870 |    8435 |   10125 | 2 |  5:51:40
level 12: 11270 |   28175 |   14090 |   16905 | 2 |  8:14:50
level 13: 18820 |   47055 |   23525 |   28230 | 2 |  11:35:20
level 14: 31430 |   78580 |   39290 |   47150 | 2 |  16:15:50
level 15: 52490 | 131230 |   65615 |   78740 | 2 |  26:25:00
level 16: 87660 | 219155 | 109575 | 131490 | 3 |  31:58:40
level 17: 146395 | 365985 | 182995 | 219590 | 3 | 44:48:40


Iron
level 11:   16870 |   13500 |    5060 |  10125 | 3 |  7:18:10
level 12:   28175 |   22540 |    8455 |  16905 | 3 |  10:16:00
level 13:   47055 |   37645 |   14115 |  28230 | 3 |  14:24:50
level 14:   78580 |   62865 |   23575 |  47150 | 3 |  20:13:10
level 15: 131230 | 104985 |   39370 |  78740 | 3 |  29:24:30
level 16: 219155 | 175320 |   65745 | 131490 | 3 |  39:43:50
level 17: 365985 | 292790 | 109795 | 219590 | 3 |  55:39:50