This has been bugging me for weeks, I add the tag but still have the default 100 map hardness, the last two maps I made have it set at 850 but with no actual change in game.

Am I missing something obvious, here is a few lines from one of the .smd`s
[MAP]
{
Description=Two giant hills, and a river of lava between them;
TidalStrength=0;
Gravity=150; //in units/sec^2
AutoShowMetal=0; // 0 no show 1 show
MaxMetal=3.50; //how much metal a map square with the
maximum metal value gives
ExtractorRadius=50; //radius that a single extractor(mine) extracts
from MapHardness=850; //terain hardness
[ATMOSPHERE]