Seeking Info on Side-Dump Mining Car

Hello,

I've recently came across the attached Barringer photo of a ng side discharge car built by ACF, with a build date of 9-19.

Being interested in this type of mining car, I am seeking information as to the Reporting marks of M.T. y A. I believe it belonged to a mining company in Mexico. I believe the "M" stand for Minera, and the "A" stands for Anexas, but not totally sure.

Two possibilities are;
Minera Trigueros y Anexas
and
Minera Tejamanil y Anexas,
but, like I said, I'm not sure.

I've been unable to locate, nor substantiate anything in early ORERs that are available to me. There maybe other ORERs for exported cars. I don't know.

I've also included a image of one of the car's unique trucks which has perforated wheels, and journal box covers that open to the side. I would also like to obtain any information about these trucks that anyone may be able to provide.

Thank you
Al Clemens