The Michigan Department of Transportation failed to provide documentation showing proper inspections of aggregates and aggregate suppliers used in road construction projects, according to an audit report released Wednesday.

Overall, the audit conducted on department records dated between October 2018 and June 2021 found three material conditions, but also said the department’s operations were sufficient, with some exceptions, in ensuring aggregate quality and moderately effective in administering its prequalified supplier program. Crusher Screen

But the audit, the department countered, failed to encompass a third level of quality review that serves as a backstop to the two tools the audit targeted. And it was conducted as the department transitions to a new construction management software system that would create a repository of testing and inspecting records and flag missing tests and inspections, said Gregg Brunner, bureau of field services director for the Michigan Department of Transportation.

"Based on the multiple levels of inspections we do, we’re confident that the material we’re using on our projects is meeting specifications," Brunner said.

The audit focused on anywhere from 14 to 50 random samples of documentation related to the 600 aggregate suppliers MDOT listed as of January 2021, zeroing in on internal processes related to quality control testing, which is performed by the supplier, and quality assurance testing and inspection performed by MDOT.

The audit did not include MDOT's processes related to visual inspections, the third tier of aggregate oversight that is usually conducted on the construction site and prior to use or payment. That visual inspection is one of the most important parts of ensuring the quality of the product, Brunner said.

"If things looked out of the ordinary at that point, we could run tests again," Brunner said.

The audit from Michigan's Auditor General found MDOT failed to retain weekly summaries of shipped aggregate materials, as required by the department, for 18 of 40 prequalified suppliers sampled, making it difficult to assess whether the agency was testing the quality of the product at required frequencies.

MDOT said six of the 18 entities cited by the auditor are inactive and wouldn’t be required to submit weekly shipping summaries.

The agency also argued the weekly shipping reports weren’t indicative of a lack of testing. Instead, quality assurance testing is done specific to each project and flagged prior to payment if not completed. But the auditor fired back that quality assurance testing is supposed to be based on the amounts shipped, not on the specifications of a certain project.

“Without the shipping summaries, MDOT cannot determine the amount of aggregate shipped by the (prequalified aggregate supplier program) suppliers and the amount of subsequent quality assurance testing it should perform,” the audit said.

The report found MDOT did not maintain a list of quality assurance laboratories nor did it conduct one or more required biennial inspections of those laboratories for 36 of 40 randomly sampled for the review.

MDOT responded that the list had been eliminated as the agency transitions to its new software and that the missing inspections occurred because of a confluence of “military deployments, employee departures and market shortage of qualified staff available to perform the functions of the work area.”

Additionally, MDOT said the rules requiring biennial inspections are changing and likely will be eliminated. The primary controls for product are the quality assurance testing and testing staff certifications, the agency said.

“As a result of staffing limitations in the aggregate area, MDOT allocated staff to areas deemed more critical than biennial inspections,” the department said.

Lastly, the audit found the department at times did not ensure suppliers met qualifications — such as laboratory inspections or complete quality control plans — prior to listing them as prequalified suppliers.

MDOT again cited staffing pressures and changing requirements as reasons for those issues.

“By April 1, 2023, MDOT will update procedures to include a quality control plan checklist and identify the areas responsible for review and completion of the checklist,” the department responded.

Hammer Rock Crusher The audit’s findings are separate from an ongoing debate in Michigan over how best to obtain aggregate for the state’s pressing infrastructure needs and whether local communities should be able to ban or limit aggregate mining operations in light of that need.