by Mr Link » September 1, 2010, 11:13 pm
Portland cement is roughly 85% lime and silica by mass. Historically cement plants in Michigan got the silica content from either clay or shale while limestone provides the lime content.
One example is the cement plant at Alpena, which ran the Paxton shale quarry about 10 miles west of Alpena. Into the mid 1980's the Detroit and Mackinac Railway would haul about 30 carloads of shale each day from Paxton to Alpena at no more than 10 miles per hour on a very minimally maintained branchline. A short time later the plant switched to using flyash as a silica source since huge amounts were available at a low cost. The quarry was closed and the branch line abandoned.
Portland cement is roughly 85% lime and silica by mass. Historically cement plants in Michigan got the silica content from either clay or shale while limestone provides the lime content.
One example is the cement plant at Alpena, which ran the Paxton shale quarry about 10 miles west of Alpena. Into the mid 1980's the Detroit and Mackinac Railway would haul about 30 carloads of shale each day from Paxton to Alpena at no more than 10 miles per hour on a very minimally maintained branchline. A short time later the plant switched to using flyash as a silica source since huge amounts were available at a low cost. The quarry was closed and the branch line abandoned.