Natural Soda recovers sodium bicarbonate using a process known as solution mining. This involves pumping heated water 1,900 feet underground to dissolve nahcolite beds and form a brine solution that is pumped to the surface and sent to the production plant.
Mining nahcolite requires very careful monitoring of temperature, pressure and flow to not only optimize production performance, but to mine the product sustainably and protect the freshwater aquifer. WirelessHART transmitters make it possible to monitor remote injection wells to protect the environment, increase efficiency and improve productivity.
Natural Soda’s Raymond Pfister wrote a cover story in InTech magazine describing how Emerson’s WirelessHART transmitters make it possible to monitor their remote injection wells. In the article, Natural Soda discusses how they use wireless technology to monitor mining operations. Ray details the problems Natural Soda faced:
Our operating permits require us to continuously monitor and record fluid temperature, pressure, and flow rate in both the recovery and injection wells. We must also keep these parameters within specified ranges as detailed in our BLM-approved mine plan. A key element of the BLM mine plan is controlling the pressure of the saline aquifer immediately above the mining zone. The mine plan specifies that the pressure in this aquifer must stay below the pressure of the upper freshwater aquifers to eliminate the potential of cross contamination between the aquifers.
In March 2013, Natural Soda completed construction of an additional production train, increasing annual production from 125,000 tpa to 250,000 tpa, making Natural Soda the second-largest producer of sodium bicarbonate in the U.S. The facility is located in mountainous and rugged terrain, making it difficult and very expensive to employ wired devices. Ray says WirelessHART solved the wiring problem, and saved a considerable amount of money:
The distances involved made this an expensive proposition, since some of the wells were more than a mile from the production plant. Installing wire and conduit the entire distance from the well fields to the DCS would have cost $80,000–$90,000. Instead, we installed a wireless I/O card (WIOC) in one of the DCS racks. It receives WirelessHART data and transfers it to the DCS. The cost of installing the WIOC was a fraction of the price of hard wiring, and it could be installed within our required timeline, saving time and approximately $70,000.
Ray reports excellent results:
The most important result of using WirelessHART flow, pressure, and temperature transmitters at the well pads is that Natural Soda can confidently operate and deliver expected results within the parameters of the BLM mine plan with no leakage into the freshwater aquifer. The system works flawlessly to protect the environment.
Not only did WirelessHART transmitters help meet regulatory requirements, they cut maintenance costs, Ray explains:
Maintenance costs have been reduced by half because the system has no fuses or power supplies, and no wires. WirelessHART status and diagnostic information indicates if any transmitter has a problem, and the system alerts the operators accordingly. If a problem does occur with any transmitter, technicians can go right to the device and troubleshoot with a HART communicator. A laptop is not required in the field for maintenance.
Natural Soda plans to keep expanding, and their WirelessHART infrastructure will make it easy:
Future plans call for installation of asset management software to enhance troubleshooting, including the installation of pump and motor health management hardware and software. The WIOC will accommodate additional well pads and wireless transmitters, which is very important, because we plan to expand production to 500,000 tpa and add wireless monitoring of tank levels in the near future.