Don't expect much to come out of the claim against the quarry. But the way the US civil trial system works, the best strategy for the complainant is to include everyone with a remote chance of being even partially responsible at the beginning of the case.
Respondents can ask (motion) the judge to be removed from the case. If there's no possible legal basis for the inclusion, the judge will grant the motion and take them out.
If they are still in the suit, it's always possible the complainant will find something during the discovery phase which will help their case. For the quarry, the complainant will be hoping to find stuff like e-mails from employees discussing whether they should close down due to the conditions or maybe a citation from a government agency over impeded access. Basically anything that will cause the quarry's insurance company to decide to settle.
Respondents can ask (motion) the judge to be removed from the case. If there's no possible legal basis for the inclusion, the judge will grant the motion and take them out.
If they are still in the suit, it's always possible the complainant will find something during the discovery phase which will help their case. For the quarry, the complainant will be hoping to find stuff like e-mails from employees discussing whether they should close down due to the conditions or maybe a citation from a government agency over impeded access. Basically anything that will cause the quarry's insurance company to decide to settle.