Every building does not need a rebuild mine method.

src/engine/objects/Building.java

@@ -89,7 +89,7 @@ public class Building extends AbstractWorldObject {
     private int maxGold;
     private int effectFlags = 0;
     private String name = "";
-    private int rank;
+    public int rank;
     private boolean ownerIsNPC = true;
     private boolean spireIsActive = false;
     private ConcurrentHashMap<String, JobContainer> timers = null;
@@ -954,17 +954,6 @@ public class Building extends AbstractWorldObject {
 
     }
 
-    public final void rebuildMine() {
-        this.setRank(1);
-        this.meshUUID = this.getBlueprint().getMeshForRank(this.rank);
-
-        // New rank mean new max hit points.
-
-        this.healthMax = this.getBlueprint().getMaxHealth(this.rank);
-        this.setCurrentHitPoints(this.healthMax);
-        this.getBounds().setBounds(this);
-    }
-
     public final void refreshGuild() {
 
         UpdateObjectMsg uom = new UpdateObjectMsg(this, 5);