Interestingly enough, the two contemporary sources that mentions this occurrence does not make the claim that the mines didn't detonate.

According to Keesing's Record of World Events (Volume 34, 1988), when Forces Armées du Nord assaulted the Libyan air base at Ouadi Doum in March 1987, the Toyotas from Chad were driven at such a speed that most of the mines would detonate after they had been driven over thus minimizing casualties.

In an article written a few months after the assault on Ouadi Doum and published in Executive Intelligence Review (Volume 14, Number 37, September 18, 1987), Mary Lalevée wrote the following:

The Chadian raid was led by 31-year-old Commander Djamous, who was responsible for major Chadian victories at Fada and Ouadi Doum earlier this year. He personally led troops in trucks over Libyan-laid minefields at Ouadi Doum, to prove that driving over the mines at 90 kilometers an hour causes a three-second delay before they explode. He was badly injured, using his own technique of "three seconds for a mine," but is now back in action and led the troops at Maatan al Sara.

Written in the context of the recent raid on Mataan al-Sara, which was a resounding Chadian victory, it shows that FANT continued to use the technique that had been previously been used in March that same year but that the mines did detonate and that they did lead to casualties - unlike what is claimed in the Wikipedia article.