What about the 48 port switch? You think I will have any IP issues with the modem?
Shouldn't be a problem. Assuming your modem is a router that supports DHCP, each machine will be assigned an IP automatically from the router. Otherwise, you may want to assign your machine IPs manually (if the machines support manual IP manual) without relying on DHCP for better manageability, because DHCP IP assignment isn't always deterministic, meaning a machine may get assigned a different IP from the DHCP pool upon reboot (unless your router support MAC address mapping) which may or may not pose a problem for your mine management solution...