From Realtà Mapei n° 37 - 2023-11-09
Chemical injection resins include polyurethane (PUR) and polyurea silicate (PUS) variations for quick and permanent stabilization applications. Filling cavities and voids is a common challenge in mining and underground construction. When Part A and Part B of a chemical grout are combined, there is an exothermic reaction during which the product turns into a foaming adhesive mass that will stop water, fill voids, and glue unstable rock into a solid mass. With our expertise and years of experience, we assist our clients in choosing the right technologies for specific uses.
The heat reaction delta is drastically different between PUR and PUS products, with the PURs being the hotter of the two. In our case studies, we have learned that when filling voids in coal mines, MAPEI UTT’s Silicajet EXP [NA: manufactured in North America] is the ideal product, because it expands 20 to 40 times but produces around half the heat as other PUR products on the market. PURs do have a critical role to play in underground mining, and MAPEI UTT’s Foamjet T [NA] has been a workhorse when it comes to stopping water, consolidating dikes or filling voids created by naturally forming vugs or faults.
MAPEI UTT’s solution for anchoring cable bolts is found in a PUS technology, Silicajet ANK [NA]. This product does not expand and has a short reaction period, making it ideal for use when installing cable bolts. Silicajet ANK obtains all its strength in the first hour after installation; therefore, miners have been able to get underneath installed cable bolts in a matter of hours, instead of days. This reduces the amount of downtime – and lost revenue – for the mine. Our miners have also found that Silicajet ANK can be pumped into hollow bar. Hollow bar is usually filled with pumpable cementitious grouts.
Our customers have been coming to us looking for an alternative to sausage-style polyester resin cartridges simply because the cartridges are becoming increasingly tough to find. The issues with the global supply chain have not been kind to polyester resin; some key ingredients are very difficult to source right now. Miners can be very risk-averse. Silicajet ANK also ensures that the components are completely and correctly mixed before they’re injected, while with sausage cartridges the quality of the mix is heavily dependent on the rod and the expertise of the operator. Bad mixing can lead to groundwater pollution since the single components can dissolve in it when left out of the reaction due to bad mixing.
We spent two years testing our chemical grout technologies with numerous stakeholders. In doing so, we have validated that our chemical grout technologies are not only useful, but better in many ways than traditional competitive technologies.
MAPEI UTT does offer our clients a complete line of cementitious grouts. Our Stabilcem T and Stabilcem AG are excellent bagged grouts designed to be used with anchor bolts and cable bolts for the stoppage of water ingress or stabilizing weak ground. Our clients have also had success with our microfine cement line of Microcem 8000 and Microcem 12000. The Blaine fineness is measured in terms of the specific area of cement expressed as total surface area in square centimeters per gram. Microcem 8000 has a cement Blaine of 8000, and Microcem 12000 has a cement Blaine of 12000. All of MAPEI UTT’s cementitious grouts have excellent pot times and incredible high early strengths.
MAPEI UTT offers complex products designed to meet the individual demands of underground and severe jobsites. Our expert team combined with our diverse range of solutions will help solve the most challenging projects with innovative, trusted technology. For more information, visit utt.mapei.com/en/home-page.
|Product Name||Description||Foam Factor|
|Stabilcem T||One-component, pre-blended, shrinkage-compensated thixotropic mortar – sanded||N/A|
|Stabilcem AG||One-component, pre-blended, shrinkage-compensated thixotropic mortar – unsanded||N/A|
|Microcem 8000||Micro-fine, hydraulic binder with pozzolanic action for ground consolidation and ground waterproofing||N/A|
|Microcem 12000||Micro-fine, hydraulic binder with pozzolanic action for ground consolidation and ground waterproofing||N/A|
|Foamjet T||High-viscosity, ultra rapid-setting, two-component polyurethane resin, injected for consolidating and waterproofing of structures subject to strong water ingress||3-10|
|Foamjet F||Ultra rapid-setting, two-component polyurethane resin with fluid consistency, injected for consolidating and waterproofing of structures subject to water ingress||20|
|Silicajet ANK||Two-component, organo-mineral resin for anchoring structural bars||–|
|Silicajet EXP||Two-component, organo-mineral, fast-reacting and high-foaming resin for void filling||30-40|