That's more than likely what's causing it. Might I suggest.
private void generateSurface(World world, Random random, int chunkX,int chunkZ){
int xCoord = chunkX;
int yCoord = random.nextInt(64);
int zCoord = chunkZ;
(new WorldGenMinable(ashtonsmod.LightSteelOre.blockID, 7)).generate(world, random, (xCoord + random.nextInt(60)), yCoord, (zCoord + random.nextInt(60)));
(new WorldGenMinable(ashtonsmod.AmethystOre.blockID, 5)).generate(world, random, (xCoord + random.nextInt(60)), yCoord, (zCoord + random.nextInt(80));
}