In late May, environmental activist Wilma Subra spoke to several hundred residents at a public forum in Mandeville. Her topic was fracking, and the audience was receptive.

On Monday, Subra again spoke to a group about fracking. But this time, the far smaller audience was skeptical, if not outright hostile.

Subra’s half-hour speech — a recap of the basics of how fracking works and the slow progress of the plan by Helis Oil & Gas Co. to put such a well in St. Tammany Parish — was given to the New Orleans Geological Society, a group formed in 1941 “with specific emphasis to exploration and production of petroleum and natural gas,” according to the group’s website.

During her comments, Subra criticized Helis for acquiring the rights to some 60,000 acres in St. Tammany Parish without the public being informed. Unlike other parishes, where parish clerks’ offices have been besieged by landmen seeking to put together parcels large enough to lease, Helis was able to acquire the acreage from just a few large landowners.

“This was all done very quietly,” she said.

Subra recounted the Helis plan’s poor reception in the parish and related the basic arguments contained in a lawsuit filed by parish government against Louisiana Commissioner of Conservation James Welsh to try to prevent Welsh from issuing the company a drilling permit.

Exasperated sighs greeted some of Subra’s comments during her speech, but it was during a question-and-answer period that things truly became contentious.

“I personally resent your insinuation that people like Helis … that when we are out leasing we should let everybody know what we are doing,” Donald Andrews said. “You have got abysmal ignorance about drilling.”

Subra apologized for offending Andrews.

Her assertion that none of the wells already in St. Tammany Parish penetrated the Tusacaloosa Marine Shale was immediately disputed by Paul Lawless, Helis’ geologic manager, who was at the talk.

“There are over 50 wells that have been drilled onshore in St. Tammany Parish, and 45 of which have been drilled through the Tuscaloosa Marine Shale,” Lawless said.

After the talk, Subra laughed off the unfriendly reception. “I am used to it,” she said.

Helis’ planned oil well in St. Tammany Parish has generated controversy from the time it came to light in April.

Almost immediately, a vociferous opposition sprang up, mobilizing on social media sites and packing public meetings.

Since an initial burst of activity, the intensity of the opposition may have diminished, but it remains resolute. Just last week, anti-fracking activists lined La. 59 outside parish government headquarters before the Parish Council voted to allot another $125,000 to the parish’s legal fight to prevent the state from issuing Helis a drilling permit.

At the same time, the St. Tammany West Chamber and the Northshore Business Council have issued reports backing Helis’ plan.

Helis has proposed drilling a 13,000-foot-deep well on the southern end of a 960-acre tract north of Interstate 12 and east of La. 1088. In addition to the drilling permit, for which Helis has yet to apply to the state, the company also must obtain a wetlands permit from the U.S. Army Corps of Engineers. That agency recently asked Helis to revise and resubmit its permit application.

Helis’ well is at the southeast tip of the Tuscaloosa Marine Shale, a rock formation that could contain as much as seven billion barrels of oil. The Tuscaloosa Marine Shale stretches from St. Tammany Parish west through the Florida Parishes across central Louisiana to Texas.

To get at the oil in the formation, drillers must drill a well horizontally and frack it. When a well is fracked, water, sand or other proppants and chemicals are pumped into the horizontal shaft at high pressure to create fissures in rock through which oil can be extracted.

The process has been controversial. Municipalities in New York, Texas, Pennsylvania and Colorado, among others, have tried to ban it with varying degrees of success.

Follow Faimon A. Roberts III on Twitter, @faimon.