A Message to Polk County Contractors

If you’ve been working in Polk for a few years, undoubtedly you have come across projects that are on land formerly mined for phosphate.  As you know, the soil can range from excellent and well compacted to extremely soft and weak.  Soil types can be grouped into the following categories:  1) Natural Sequence - sand overlying stiff clays and limestone;  2) Sand Tailings - generally, clean, fine sand; 3) Overburden - usually a mixture of sand and clay, also with pockets of sand or clay; and 4) Slimes - this is a mining term referring to waste phosphatic clay.  This is a man-made clay that is one of the most plastic in the world, often with Plasticity Indices (PI) over 100.  You may or may not know what a “PI” is, but 100 is very bad.  The clay is usually extremely wet and highly compressible.  In some cases, waste phosphatic clay deposits have been known to consolidate over 10 feet in thickness, that is, more than half the original thickness of the deposit.  Some areas in Polk County that have been or are being developed and are known for waste clay deposits are the Christina and Oakbridge Subdivisions.
 

Before PhosphoCrete™, the options to deal with these clay deposits included piling, excavate and replace with good soil, surcharging, or post-tensioned foundations.  The limitations of these options have been high cost and/or the time frame to implement.  PhosphoCrete™ overcomes both of these limitations.  MEG has advanced the state-of-practice for this technology, making it lower cost and fast acting.  What this means to you is that more ‘marginal land’ can be developed - putting money in your pocket.