Fabio, fíjate en la 2ª foto de este enlace:
https://www.tunneltalk.com/Seattle-Alaskan-Way-12March2015-U...
Te copio por si sirve de algo las entradas del Ernst 2004 EN-ES:
gantry = andamio (sobre rodillos); puente elevador; torre de montaje; combo (de barriles). Quizá optaría por pórtico como solución general, con toda la prudencia.
Espero que te oriente

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Note added at 9 horas (2021-05-13 04:15:06 GMT)
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PS: un gantry es una -grúa pórtico- en general, comparar imágenes:

https://www.google.es/search?q="gantry"&source=lnms&tbm=isch...

https://www.google.es/search?q="grúa pórtico"&tbm=isch&ved=2...

En tu caso no sé si realmente hay una grúa o no, por prudencia sigo pensando que lo mejor es dejarlo en pórtico si nadie aporta más evidencias sólidas.


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Note added at 11 horas (2021-05-13 06:04:17 GMT)
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Copio varias entradas generales de kudoz (ojo no son específicas de minería), sí parecen apuntar a pórtico como solución general:

https://www.proz.com/kudoz/spanish-to-english/fisheries/3493...
https://www.proz.com/personal-glossaries/entry/788230-portiq...
https://www.proz.com/kudoz/french-to-english/automotive-cars...
https://www.proz.com/kudoz/dutch-to-english/ships-sailing-ma...
https://www.proz.com/kudoz/dutch-to-english/ships-sailing-ma...
https://www.proz.com/kudoz/english-to-norwegian/other/584255...
https://www.proz.com/personal-glossaries/entry/22152388-gant...
https://www.proz.com/personal-glossaries/entry/18890246-gant...
https://www.proz.com/personal-glossaries/entry/786582-gantry...
https://www.proz.com/kudoz/english-to-portuguese/engineering...

The photos in this first reference shows what a TBM gantry is, and describes it as follows:

"Resembling an oblong cage, this gantry will serve as a sort of supporting skeleton trailing behind the machine’s rotating drill head. It will house conveyor belts, propulsion systems, and equipment used to reinforce tunnel walls as the TBM burrows ahead."
https://chicago.curbed.com/2018/7/10/17549684/elon-musk-bori...

Likewise, this second reference has photos of a TBM gantry and describes it as follows:

"Designed for the service after the Tunnel Boring Machine works. The machine is located in front of the secondary lining system and it is designed for the removal of the provisions left by the TBM such as working platforms, rails and pipes. The TBM Gantry is supplied with the following provisions:

- Diesel generators for the hydraulic power pack feeding
- Joystick control station in the front and in the back of the gantry
- Electric winches for the removal of working platforms and pipes
- Electric winches for the removal of the rails
- 4WD drive units
- PLC system to control the advancement of the gantry avoiding any misalignment of the drive units running on the segments."
http://www.kern-tunneltechnik.com/en/prodotto/12/tbm-gantry

This last reference describes the purpose of a TBM gantry:

"The next exciting phase is putting everything together. We’ll position the shield inside the first 50m of the CRL tunnel and connect the shield to the TBM’s “’factory’ – the 11 sections or gantries that provide the hydraulic, mechanical and electrical power the shield will need to excavate the tunnels, remove the excavated spoil, and install the precast concrete segments that will line the tunnels. When all the gantries are connected the TBM will undergo extensive commissioning tests and trials before to starts excavating the first of the twin 1.6km long CRL tunnels in late April."
https://tunnellingjournal.com/auckland-city-rail-link-tbm-mo...

This paper by Crossrail (click on 'read the full document') on two of its TBMs shows Figure 1.2(b) – Typical TBM Gantry Configurations, and describes what the gantries do and how they are moved along behind the boring section.
https://learninglegacy.crossrail.co.uk/documents/tbm-station...