Augury could help depending on how it is interpreted. Based on the accepted answer to "How does the timing on Augury work?", the action specified in the casting of the spell only needs to be begun in the next 30 minutes not completed. As such Ichabod the Inscrutable could, over a series of days, ask about sending out a questing party to various places to inquire about the ingot. Eventually he might receive a weal sign and so send the party and gain further insight into the ingot. He should test this with different parties, and multiple routes to the same location so as to prevent the evil necromancer in the mountain pass from causing all results to be woe.
Commune can certainly help in narrowing down the ingots place of origin. Questions might be: Does the place where this ingot was mined lie to the north of my current location? Is this ingot's place of origin within 100 miles of the tower of Bazilior the Blue? Is there someone in the city of Adelburgh who can tell me where this ingot was forged?
Legend Lore can help at various points of the investigation by supplementing Ichabod's knowledge of the ingot or of anything Ichabod learns relating to the ingot. Since the ingot is probably not legendary the spell likely will not turn up great results but the city where is was mined or the smith who cast it might be legendary.
Scrying once Ichabod learns something of the ingots maker/miner/transporter can help Ichabod find that person to gain further information. Ichabod will likely frequently fail at this considering the target will have at least a +5 to the save until Ichabod succeeds and the spell might just fail if Ichabod does not have enough information to specify a specific person.
Find the Path can assist if Ichabod successfully scrys someone or receives sufficient information from Legend Lore or the questing party as to be "familiar" with the ingot's place of origin. Casting the spell will allow Ichabod to determine the exact location by considering the direction and distance to the destination.