(1) "Invested" includes, but is not limited to, expenditures made from the proceeds of bonds, including interim notes or other evidence of indebtedness, issued by a municipality, county, or an agency or instrumentality of a municipality, county, or the State of Arkansas, if the obligation to repay the bonds, including interest thereon, is a legally binding obligation, directly or indirectly, of the taxpayer;

(2) "Production, processing, and testing equipment" includes machinery and equipment essential for the receiving, storing, processing, and testing of raw materials and the production, storage, testing, and shipping of finished products, and facilities for the production of steam, electricity, chemicals, and other materials that are essential to the manufacturing process but which are consumed in the manufacturing process and do not become essential components of the finished product; and

(3) "Qualified manufacturer of steel" means any natural person, company, or corporation engaged in the manufacture, refinement, or processing of steel whenever more than fifty percent (50%) of the electricity or more than fifty percent (50%) of the natural gas consumed in the manufacture, refinement, or processing of steel is used to power an electric arc furnace or furnaces, continuous casting equipment, or rail steel mill equipment in connection with the melting, continuous casting, or rolling of steel or in the preheating of steel for processing through a rail steel mill.