shares of common stock at a price to the public of $0.42 per share (the “Offering Shares”). In addition, we granted the Underwriters an option to purchase, at the public offering price per share of common stock, up to an additional 2,678,571 shares of common stock, exercisable for 30 days from the date of the Underwriting Agreement (the “Option Shares”). The Offering Shares and Option Shares were registered pursuant to our registration statement on Form S-3 (File No. 333-220461), and a prospectus supplement thereto filed with the Securities and Exchange Commission. The Underwriters acquired the Offering Shares and the full amount of the Option Shares from us with an underwriting discount of six percent (6%) and we also agreed to reimburse them for customary fees and expenses. After the underwriting discount of 6% and total offering expenses of approximately $225,000 we received net proceeds of approximately $7.9 million from the sale of the Offering Shares and the Option Shares. We intend to use the proceeds from the Offering for working capital requirements and general corporate purposes. The sale of the Offering Shares and Option Shares closed on July 24, 2020.
In connection with the Offering, the Company, its directors, executive officers, and certain stockholders, subject to certain exceptions, agreed to not sell or transfer any shares of common stock or securities convertible into, or exchangeable or exercisable for, the Company’s shares of common stock during a period ending 90 days after the closing of the Offering. This includes the Company’s use of the LPC Program and the ATM Program.
Offering and private placement transaction
On April 20, 2020, we entered into a securities purchase agreement with certain institutional investors providing for the issuance and sale of 15,000,000 shares of our common stock at a price of $0.20 per share, and in a concurrent private placement transaction, the issuance of 11,250,000 warrants, ultimately consisting of 7,500,000 series A warrants and 3,750,000 series B warrants, to purchase up to 11,250,000 shares of our common stock at an exercise price of $0.30 per share, for aggregate gross proceeds of $3.0 million. The securities purchase agreement contains customary representations, warranties and covenants, in addition to granting the investors the right to collectively participate in up to 50% of any future offerings of securities by the Company on the same terms as other investors, other than certain “exempt issuances” and “permitted sales” as defined therein, until the first anniversary of the closing date of the offering.
Each Warrant is exercisable six months from April 22, 2020, the date of issuance, and has a term expiring five years after such initial exercise date. The Warrants contain so-called full-ratchet anti-dilution provisions which may be triggered upon any future issuance by the Company of shares of its common stock or common stock equivalents at a per share price below the then-exercise price of the Warrant, subject to certain exceptions; provided, however, that with respect to the Series B warrants, the adjusted exercise price will not be less than $0.26.
Total costs for the offering were approximately $290,000, including the placement agent fee of six percent of the aggregate gross proceeds, except, however, that a reduced fee was accepted with respect to one investor.
Financial Results of Operations
For the results of continuing operations discussed below, we compare the results from operations for the three and six months ended June 30, 2020 to the results from operations for the three and six months ended June 30, 2019.
Three Months Ended June 30, 2020
Revenue from oxide plant lease. We recorded revenue of $1.2 million and $2.0 million during three-month periods ended June 30, 2020 and 2019, respectively, related to the lease of our Velardeña oxide plant to a third party. The decrease in revenue during 2020 is primarily related to a reduction in the per tonne processing fees during the period relating to the Third Amendment to the Hecla lease as discussed in Note 19 in the accompanying financial statements. In addition, during 2020 we experienced a temporary shutdown of operations during a portion of April and May 2020 related to COVID-19 restrictions mandated by the Mexican government.
Oxide plant lease costs. We recorded $0.4 million and $0.6 million of costs related to the oxide plant lease during of the three-month periods ended June 30, 2020 and 2019, respectively. The costs consist primarily of reimbursable labor and utility costs which for accounting purposes are also included in revenue from the oxide plant lease.
Exploration expense. Our exploration expense, including work at Sand Canyon, Rodeo and other properties, property holding costs and allocated administrative expenses, totaled $0.8 million and $1.3 million for the three months ended June