In Labor Unions, a binding settlement takes place when arbitration or other decisions are final and accepted by law or by both parties. By definition, a binding settlement resolves an unresolved dispute.
To properly address an unresolved dispute, most unions bring in the services of a third-party arbiter, who acts as a neutral view of the dispute. This can be in service of a strike, where employees walk off the workforce, or in service of a grievance claim against management. The arbiter examines claims on both sides and negotiates to resolve the situation. To resolve the problem, the labor contract may be amended or renegotiated entirely. This can be either proper binding arbitration, or non-binding mediation.
Both parties seek a fair and equal end result from the negotiation process. The union seeks to find the best terms for its members, and management seeks to find the best terms for its bargaining power with the union. Assuming there are no severe grievances on either side, and no legal problems with the contract or working conditions, the two parties either agree the terms of one side, or come to a middle-ground seen as fair by both. In an arbitration situtation for an unresolved dispute, the decision of the arbiter is binding, meaning that both parties must abide by the new terms and conditions.