Hey can someone tell me why my ore wont spawn?

package net.minecraft.src;

import java.util.Random;

public class mod_EmeraldsN extends BaseMod
{
public void load()
{
ModLoader.registerBlock(emeraldOre);
ModLoader.addName(emeraldOre, "emeraldOre");
}

public static int emeraldoreID = 159;
//Initialization
public static Block emeraldOre;
//Block Definitions
static
{
emeraldOre = new BlockEmeraldOreN(emeraldoreID,0).setHardness(2.0F).setBlockName("EmeraldOre").setResistance(20.0F);
emeraldOre.blockIndexInTexture = ModLoader.addOverride("/terrain.png", "/TMC/emeraldOre.png");
}
public String getVersion()
{
return "Minecraft 1.2.3";
}

public void GenerateSurface(World world, Random rand, int chunkX, int chunkZ)
{
for(int i = 0; i < 45; i++)
{
int randPosX = chunkX + rand.nextInt(16);
int randPosY = rand.nextInt(64);
int randPosZ = chunkZ + rand.nextInt(16);
(new WorldGenMinable(mod_EmeraldsN.emeraldOre.blockID, 20)).generate(world, rand, randPosX, randPosY, randPosZ);
}
}
}

hmmmm for me, i might just quit my modding because 1.2 made it HARDER!