Fix for multiple quarry arms.

common/net/minecraft/src/buildcraft/factory/EntityMechanicalArm.java

@@ -12,6 +12,7 @@ package net.minecraft.src.buildcraft.factory;
 import net.minecraft.src.BuildCraftFactory;
 import net.minecraft.src.Entity;
 import net.minecraft.src.NBTTagCompound;
+import net.minecraft.src.TileEntity;
 import net.minecraft.src.World;
 import net.minecraft.src.buildcraft.core.EntityBlock;
 
@@ -32,12 +33,13 @@ public class EntityMechanicalArm extends Entity {
 	boolean inProgressionXZ = false;
 	boolean inProgressionY = false;
 	
+	protected TileEntity parent;
+	
 	public EntityMechanicalArm(World world) {
 		super(world);
 	}
 
-	public EntityMechanicalArm(World world, double i, double j, double k,
+	public EntityMechanicalArm(World world, double i, double j, double k, double width, double height, TileEntity parent) {
-			double width, double height) {
 		super(world);
 
 		setPosition(i, j, k);
@@ -79,6 +81,8 @@ public class EntityMechanicalArm extends Entity {
 		head.shadowSize = 1.0F;
 
 		updatePosition();
+		
+		this.parent = parent;
 	}
 
 	@Override
@@ -186,6 +190,12 @@ public class EntityMechanicalArm extends Entity {
 
 	@Override
 	public void onUpdate() {
+		
+		if (parent != null && worldObj.getBlockTileEntity(parent.xCoord, parent.yCoord, parent.zCoord) != parent) {
+			setDead();
+			return;
+		}
+		
 		if (speed > 0) {
 			doMove(speed);
 		}

common/net/minecraft/src/buildcraft/factory/TileQuarry.java

@@ -120,7 +120,7 @@ public class TileQuarry extends TileMachine implements IArmListener, IMachine,
 				yCoord + bluePrintBuilder.bluePrint.sizeY - 1
 						+ Utils.pipeMinPos, box.zMin + Utils.pipeMaxPos,
 				bluePrintBuilder.bluePrint.sizeX - 2 + Utils.pipeMinPos * 2,
-				bluePrintBuilder.bluePrint.sizeZ - 2 + Utils.pipeMinPos * 2);
+				bluePrintBuilder.bluePrint.sizeZ - 2 + Utils.pipeMinPos * 2, this);
 
 		arm.listener = this;
 		loadArm = true;
@@ -456,8 +456,9 @@ public class TileQuarry extends TileMachine implements IArmListener, IMachine,
 	}
 
 	@Override
-	public void invalidate() {
+	public void invalidate () {		
-		destroy();
+		System.out.println("hi");
+		destroy ();
 	}
 
 	@Override