Pickaxe Collision Problems

I'm a beginner with Unity 3D and I'm trying to create a 3D survival game. I have modeled a pickaxe in 3ds Max and parented it to a FirstPersonControllerPrefab. In my script which I have written to show the collision between the pickaxe and another object (i.e. a rock) I have it print a message to the debug log and create some sparks when I left click on the other object.

The problem I am having is that when the collider on the pickaxe enters the other object nothing happens, the collision is not recorded. I have tried two boxes as a test, one with a rigidbody and one without. Both have colliders. The small sphere on the end of the pickaxe has the pickCollider script attached to it.

The FPController has a rigidbody attached and I tried adding a rigidbody to the pickaxe as a solution but it just screwed up everything and went all funny :P

Any help is greatly appreciated :D

My script:

var sparksPrefab : Transform; var audioclip : AudioClip;

function OnTriggerEnter(myCollider : Collision){

 if(Input.GetButton("Fire1")){
     Debug.Log("Pick hit something!");
     var contact = myCollider.contacts[0];
     var rot = Quaternion.FromToRotation(Vector3.up, contact.normal);
     var pos = contact.point;
     Instantiate(sparksPrefab, pos, rot);
     audio.PlayOneShot(audioclip);
         }

}